From 1644d64398491d4a324a5eee492d1fd37df52a01 Mon Sep 17 00:00:00 2001
From: FDIM <domas.trijonis@gmail.com>
Date: Tue, 9 Mar 2021 21:20:48 +0100
Subject: [PATCH] feat(compiler-cli): introduce HttpContext request context
 (#25751)

A long-requested feature for HttpClient is the ability to store and retrieve
custom metadata for requests, especially in interceptors. This commit
implements this functionality via a new context object for requests.

Each outgoing HttpRequest now has an associated "context", an instance of
the HttpContext class. An HttpContext can be provided when making a request,
or if not then an empty context is created for the new request. This context
shares its lifecycle with the entire request, even across operations that
change the identity of the HttpRequest instance such as RxJS retries.

The HttpContext functions as an expando. Users can create typed tokens as instances of HttpContextToken, and
read/write a value for the key from any HttpContext object.

This commit implements the HttpContext functionality. A followup commit will
add angular.io documentation.

PR Close #25751
---
 goldens/public-api/common/http/http.d.ts  | 139 ++++++++++++++++++++++
 goldens/size-tracking/aio-payloads.json   |  10 +-
 packages/common/http/public_api.ts        |   1 +
 packages/common/http/src/client.ts        | 133 +++++++++++++++++++++
 packages/common/http/src/context.ts       |  99 +++++++++++++++
 packages/common/http/src/request.ts       |  29 +++++
 packages/common/http/test/context_spec.ts |  59 +++++++++
 packages/common/http/test/module_spec.ts  | 126 ++++++++++++--------
 packages/common/http/test/request_spec.ts |  14 +++
 9 files changed, 556 insertions(+), 54 deletions(-)
 create mode 100644 packages/common/http/src/context.ts
 create mode 100644 packages/common/http/test/context_spec.ts

diff --git a/goldens/public-api/common/http/http.d.ts b/goldens/public-api/common/http/http.d.ts
index 0b6c33c7a6..9eb12e7746 100644
--- a/goldens/public-api/common/http/http.d.ts
+++ b/goldens/public-api/common/http/http.d.ts
@@ -10,6 +10,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -22,6 +23,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -34,6 +36,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -47,6 +50,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -59,6 +63,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -71,6 +76,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -83,6 +89,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -95,6 +102,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | (string | number | boolean)[];
         };
@@ -107,6 +115,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -119,6 +128,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -131,6 +141,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -143,6 +154,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -155,6 +167,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -166,6 +179,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -178,6 +192,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -190,6 +205,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -202,6 +218,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -214,6 +231,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -227,6 +245,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -239,6 +258,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -251,6 +271,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -263,6 +284,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -275,6 +297,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -287,6 +310,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -299,6 +323,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -311,6 +336,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -323,6 +349,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -335,6 +362,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -346,6 +374,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -358,6 +387,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -370,6 +400,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -382,6 +413,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -394,6 +426,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -407,6 +440,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -419,6 +453,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -431,6 +466,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -443,6 +479,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -455,6 +492,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -467,6 +505,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -479,6 +518,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -491,6 +531,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -503,6 +544,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -515,6 +557,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -526,6 +569,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -538,6 +582,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -552,6 +597,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -564,6 +610,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -576,6 +623,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -589,6 +637,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -601,6 +650,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -613,6 +663,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -625,6 +676,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -637,6 +689,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -649,6 +702,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -661,6 +715,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -673,6 +728,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -685,6 +741,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -697,6 +754,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -708,6 +766,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -720,6 +779,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -732,6 +792,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -744,6 +805,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -756,6 +818,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -769,6 +832,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -781,6 +845,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -793,6 +858,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -805,6 +871,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -817,6 +884,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -829,6 +897,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -841,6 +910,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -853,6 +923,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -865,6 +936,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -877,6 +949,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -888,6 +961,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -900,6 +974,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -912,6 +987,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -924,6 +1000,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -936,6 +1013,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -949,6 +1027,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -961,6 +1040,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -973,6 +1053,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -985,6 +1066,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -997,6 +1079,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1009,6 +1092,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1021,6 +1105,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1033,6 +1118,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1045,6 +1131,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1057,6 +1144,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1068,6 +1156,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1080,6 +1169,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1092,6 +1182,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1104,6 +1195,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1116,6 +1208,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1129,6 +1222,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1141,6 +1235,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1153,6 +1248,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1165,6 +1261,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1177,6 +1274,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1189,6 +1287,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1201,6 +1300,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1213,6 +1313,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1225,6 +1326,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1237,6 +1339,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1248,6 +1351,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1260,6 +1364,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1274,6 +1379,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1287,6 +1393,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1300,6 +1407,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1313,6 +1421,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1327,6 +1436,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1340,6 +1450,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'events';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1352,6 +1463,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         reportProgress?: boolean;
         observe: 'events';
         params?: HttpParams | {
@@ -1365,6 +1477,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         reportProgress?: boolean;
         observe: 'events';
         params?: HttpParams | {
@@ -1379,6 +1492,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1392,6 +1506,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1405,6 +1520,7 @@ export declare class HttpClient {
             [header: string]: string | string[];
         };
         observe: 'response';
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1417,6 +1533,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         reportProgress?: boolean;
         observe: 'response';
         params?: HttpParams | {
@@ -1430,6 +1547,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         reportProgress?: boolean;
         observe: 'response';
         params?: HttpParams | {
@@ -1443,6 +1561,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1456,6 +1575,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         observe?: 'body';
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
@@ -1469,6 +1589,7 @@ export declare class HttpClient {
         headers?: HttpHeaders | {
             [header: string]: string | string[];
         };
+        context?: HttpContext;
         params?: HttpParams | {
             [param: string]: string | number | boolean | ReadonlyArray<string | number | boolean>;
         };
@@ -1493,6 +1614,18 @@ export declare class HttpClientXsrfModule {
     }): ModuleWithProviders<HttpClientXsrfModule>;
 }
 
+export declare class HttpContext {
+    delete(token: HttpContextToken<unknown>): HttpContext;
+    get<T>(token: HttpContextToken<T>): T;
+    keys(): IterableIterator<HttpContextToken<unknown>>;
+    set<T>(token: HttpContextToken<T>, value: T): HttpContext;
+}
+
+export declare class HttpContextToken<T> {
+    readonly defaultValue: () => T;
+    constructor(defaultValue: () => T);
+}
+
 export declare interface HttpDownloadProgressEvent extends HttpProgressEvent {
     partialText?: string;
     type: HttpEventType.DownloadProgress;
@@ -1598,6 +1731,7 @@ export declare interface HttpProgressEvent {
 
 export declare class HttpRequest<T> {
     readonly body: T | null;
+    readonly context: HttpContext;
     readonly headers: HttpHeaders;
     readonly method: string;
     readonly params: HttpParams;
@@ -1608,6 +1742,7 @@ export declare class HttpRequest<T> {
     readonly withCredentials: boolean;
     constructor(method: 'DELETE' | 'GET' | 'HEAD' | 'JSONP' | 'OPTIONS', url: string, init?: {
         headers?: HttpHeaders;
+        context?: HttpContext;
         reportProgress?: boolean;
         params?: HttpParams;
         responseType?: 'arraybuffer' | 'blob' | 'json' | 'text';
@@ -1615,6 +1750,7 @@ export declare class HttpRequest<T> {
     });
     constructor(method: 'POST' | 'PUT' | 'PATCH', url: string, body: T | null, init?: {
         headers?: HttpHeaders;
+        context?: HttpContext;
         reportProgress?: boolean;
         params?: HttpParams;
         responseType?: 'arraybuffer' | 'blob' | 'json' | 'text';
@@ -1622,6 +1758,7 @@ export declare class HttpRequest<T> {
     });
     constructor(method: string, url: string, body: T | null, init?: {
         headers?: HttpHeaders;
+        context?: HttpContext;
         reportProgress?: boolean;
         params?: HttpParams;
         responseType?: 'arraybuffer' | 'blob' | 'json' | 'text';
@@ -1630,6 +1767,7 @@ export declare class HttpRequest<T> {
     clone(): HttpRequest<T>;
     clone(update: {
         headers?: HttpHeaders;
+        context?: HttpContext;
         reportProgress?: boolean;
         params?: HttpParams;
         responseType?: 'arraybuffer' | 'blob' | 'json' | 'text';
@@ -1646,6 +1784,7 @@ export declare class HttpRequest<T> {
     }): HttpRequest<T>;
     clone<V>(update: {
         headers?: HttpHeaders;
+        context?: HttpContext;
         reportProgress?: boolean;
         params?: HttpParams;
         responseType?: 'arraybuffer' | 'blob' | 'json' | 'text';
diff --git a/goldens/size-tracking/aio-payloads.json b/goldens/size-tracking/aio-payloads.json
index 8bec747595..ec56092f40 100755
--- a/goldens/size-tracking/aio-payloads.json
+++ b/goldens/size-tracking/aio-payloads.json
@@ -12,8 +12,8 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 3033,
-        "main-es2015": 451402,
-        "polyfills-es2015": 52215
+        "main-es2015": 452165,
+        "polyfills-es2015": 52493
       }
     }
   },
@@ -21,9 +21,9 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 3153,
-        "main-es2015": 437005,
-        "polyfills-es2015": 52215
+        "main-es2015": 437810,
+        "polyfills-es2015": 52493
       }
     }
   }
-}
+}
\ No newline at end of file
diff --git a/packages/common/http/public_api.ts b/packages/common/http/public_api.ts
index 2e3f588d6d..036e3efb60 100644
--- a/packages/common/http/public_api.ts
+++ b/packages/common/http/public_api.ts
@@ -8,6 +8,7 @@
 
 export {HttpBackend, HttpHandler} from './src/backend';
 export {HttpClient} from './src/client';
+export {HttpContext, HttpContextToken} from './src/context';
 export {HttpHeaders} from './src/headers';
 export {HTTP_INTERCEPTORS, HttpInterceptor} from './src/interceptor';
 export {JsonpClientBackend, JsonpInterceptor} from './src/jsonp';
diff --git a/packages/common/http/src/client.ts b/packages/common/http/src/client.ts
index ee5b434a37..627610a272 100644
--- a/packages/common/http/src/client.ts
+++ b/packages/common/http/src/client.ts
@@ -11,6 +11,7 @@ import {Observable, of} from 'rxjs';
 import {concatMap, filter, map} from 'rxjs/operators';
 
 import {HttpHandler} from './backend';
+import {HttpContext} from './context';
 import {HttpHeaders} from './headers';
 import {HttpParams, HttpParamsOptions} from './params';
 import {HttpRequest} from './request';
@@ -30,6 +31,7 @@ import {HttpEvent, HttpResponse} from './response';
 function addBody<T>(
     options: {
       headers?: HttpHeaders|{[header: string]: string | string[]},
+      context?: HttpContext,
       observe?: 'body'|'events'|'response',
       params?: HttpParams|
             {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -41,6 +43,7 @@ function addBody<T>(
   return {
     body,
     headers: options.headers,
+    context: options.context,
     observe: options.observe,
     params: options.params,
     reportProgress: options.reportProgress,
@@ -129,6 +132,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -149,6 +153,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -169,6 +174,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -190,6 +196,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
           observe: 'events',
@@ -211,6 +218,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -231,6 +239,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -251,6 +260,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     reportProgress?: boolean, observe: 'events',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -272,6 +282,7 @@ export class HttpClient {
   request<R>(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     reportProgress?: boolean, observe: 'events',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -292,6 +303,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -310,6 +322,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -329,6 +342,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -349,6 +363,7 @@ export class HttpClient {
   request(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     reportProgress?: boolean, observe: 'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -369,6 +384,7 @@ export class HttpClient {
   request<R>(method: string, url: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     reportProgress?: boolean, observe: 'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -389,6 +405,7 @@ export class HttpClient {
   request(method: string, url: string, options?: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -410,6 +427,7 @@ export class HttpClient {
   request<R>(method: string, url: string, options?: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -430,6 +448,7 @@ export class HttpClient {
   request(method: string, url: string, options?: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     observe?: 'body'|'events'|'response',
@@ -467,6 +486,7 @@ export class HttpClient {
   request(first: string|HttpRequest<any>, url?: string, options: {
     body?: any,
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -506,6 +526,7 @@ export class HttpClient {
       // Construct the request.
       req = new HttpRequest(first, url!, (options.body !== undefined ? options.body : null), {
         headers,
+        context: options.context,
         params,
         reportProgress: options.reportProgress,
         // By default, JSON is assumed to be returned for all calls.
@@ -592,6 +613,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -611,6 +633,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -629,6 +652,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -648,6 +672,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -666,6 +691,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -684,6 +710,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -702,6 +729,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -721,6 +749,7 @@ export class HttpClient {
    */
   delete<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | (string | number | boolean)[]},
     reportProgress?: boolean,
@@ -739,6 +768,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -756,6 +786,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -773,6 +804,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -791,6 +823,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -809,6 +842,7 @@ export class HttpClient {
    */
   delete<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -827,6 +861,7 @@ export class HttpClient {
    */
   delete(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -846,6 +881,7 @@ export class HttpClient {
    */
   delete<T>(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -865,6 +901,7 @@ export class HttpClient {
    */
   delete(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -887,6 +924,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -905,6 +943,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -923,6 +962,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -942,6 +982,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -959,6 +1000,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -976,6 +1018,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -993,6 +1036,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1011,6 +1055,7 @@ export class HttpClient {
    */
   get<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1030,6 +1075,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -1048,6 +1094,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -1066,6 +1113,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -1084,6 +1132,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1103,6 +1152,7 @@ export class HttpClient {
    */
   get<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1122,6 +1172,7 @@ export class HttpClient {
    */
   get(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1141,6 +1192,7 @@ export class HttpClient {
    */
   get<T>(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1156,6 +1208,7 @@ export class HttpClient {
    */
   get(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1178,6 +1231,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1197,6 +1251,7 @@ export class HttpClient {
 
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1215,6 +1270,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1234,6 +1290,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -1252,6 +1309,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -1270,6 +1328,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -1288,6 +1347,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1307,6 +1367,7 @@ export class HttpClient {
    */
   head<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1326,6 +1387,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -1344,6 +1406,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -1362,6 +1425,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -1380,6 +1444,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1399,6 +1464,7 @@ export class HttpClient {
    */
   head<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1417,6 +1483,7 @@ export class HttpClient {
    */
   head(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1437,6 +1504,7 @@ export class HttpClient {
    */
   head<T>(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1454,6 +1522,7 @@ export class HttpClient {
    */
   head(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1525,6 +1594,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1543,6 +1613,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1561,6 +1632,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1580,6 +1652,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -1598,6 +1671,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -1616,6 +1690,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -1634,6 +1709,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1653,6 +1729,7 @@ export class HttpClient {
    */
   options<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1672,6 +1749,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -1690,6 +1768,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -1708,6 +1787,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -1726,6 +1806,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1745,6 +1826,7 @@ export class HttpClient {
    */
   options<T>(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1763,6 +1845,7 @@ export class HttpClient {
    */
   options(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1782,6 +1865,7 @@ export class HttpClient {
    */
   options<T>(url: string, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1799,6 +1883,7 @@ export class HttpClient {
    */
   options(url: string, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1821,6 +1906,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1840,6 +1926,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1859,6 +1946,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -1880,6 +1968,7 @@ export class HttpClient {
 
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -1899,6 +1988,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -1918,6 +2008,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -1937,6 +2028,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1957,6 +2049,7 @@ export class HttpClient {
    */
   patch<T>(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -1977,6 +2070,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -1996,6 +2090,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -2015,6 +2110,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -2034,6 +2130,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2054,6 +2151,7 @@ export class HttpClient {
    */
   patch<T>(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2073,6 +2171,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2094,6 +2193,7 @@ export class HttpClient {
    */
   patch<T>(url: string, body: any|null, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2109,6 +2209,7 @@ export class HttpClient {
    */
   patch(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2131,6 +2232,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2150,6 +2252,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2169,6 +2272,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2189,6 +2293,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -2207,6 +2312,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -2226,6 +2332,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -2245,6 +2352,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2265,6 +2373,7 @@ export class HttpClient {
    */
   post<T>(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2285,6 +2394,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -2304,6 +2414,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -2323,6 +2434,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -2342,6 +2454,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2363,6 +2476,7 @@ export class HttpClient {
    */
   post<T>(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2382,6 +2496,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2403,6 +2518,7 @@ export class HttpClient {
    */
   post<T>(url: string, body: any|null, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2419,6 +2535,7 @@ export class HttpClient {
    */
   post(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2441,6 +2558,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2460,6 +2578,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2479,6 +2598,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2499,6 +2619,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -2518,6 +2639,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -2537,6 +2659,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -2556,6 +2679,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2576,6 +2700,7 @@ export class HttpClient {
    */
   put<T>(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'events',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2596,6 +2721,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'arraybuffer',
@@ -2615,6 +2741,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'blob',
@@ -2634,6 +2761,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean, responseType: 'text',
@@ -2653,6 +2781,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2673,6 +2802,7 @@ export class HttpClient {
    */
   put<T>(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]}, observe: 'response',
+    context?: HttpContext,
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
     reportProgress?: boolean,
@@ -2692,6 +2822,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2712,6 +2843,7 @@ export class HttpClient {
    */
   put<T>(url: string, body: any|null, options?: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
@@ -2728,6 +2860,7 @@ export class HttpClient {
    */
   put(url: string, body: any|null, options: {
     headers?: HttpHeaders|{[header: string]: string | string[]},
+    context?: HttpContext,
     observe?: 'body'|'events'|'response',
     params?: HttpParams|
           {[param: string]: string | number | boolean | ReadonlyArray<string|number|boolean>},
diff --git a/packages/common/http/src/context.ts b/packages/common/http/src/context.ts
new file mode 100644
index 0000000000..50a9858330
--- /dev/null
+++ b/packages/common/http/src/context.ts
@@ -0,0 +1,99 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/**
+ * A token used to manipulate and access values stored in `HttpContext`.
+ *
+ * @publicApi
+ */
+export class HttpContextToken<T> {
+  constructor(public readonly defaultValue: () => T) {}
+}
+
+/**
+ * Http context stores arbitrary user defined values and ensures type safety without
+ * actually knowing the types. It is backed by a `Map` and guarantees that keys do not clash.
+ *
+ * This context is mutable and is shared between cloned requests unless explicitly specified.
+ *
+ * @usageNotes
+ *
+ * ### Usage Example
+ *
+ * ```typescript
+ * // inside cache.interceptors.ts
+ * export const IS_CACHE_ENABLED = new HttpContextToken<boolean>(() => false);
+ *
+ * export class CacheInterceptor implements HttpInterceptor {
+ *
+ *   intercept(req: HttpRequest<any>, delegate: HttpHandler): Observable<HttpEvent<any>> {
+ *     if (req.context.get(IS_CACHE_ENABLED) === true) {
+ *       return ...;
+ *     }
+ *     return delegate.handle(req);
+ *   }
+ * }
+ *
+ * // inside a service
+ *
+ * this.httpClient.get('/api/weather', {
+ *   context: new HttpContext().set(IS_CACHE_ENABLED, true)
+ * }).subscribe(...);
+ * ```
+ *
+ * @publicApi
+ */
+export class HttpContext {
+  private readonly map = new Map<HttpContextToken<unknown>, unknown>();
+
+  /**
+   * Store a value in the context. If a value is already present it will be overwritten.
+   *
+   * @param token The reference to an instance of `HttpContextToken`.
+   * @param value The value to store.
+   *
+   * @returns A reference to itself for easy chaining.
+   */
+  set<T>(token: HttpContextToken<T>, value: T): HttpContext {
+    this.map.set(token, value);
+    return this;
+  }
+
+  /**
+   * Retrieve the value associated with the given token.
+   *
+   * @param token The reference to an instance of `HttpContextToken`.
+   *
+   * @returns The stored value or default if one is defined.
+   */
+  get<T>(token: HttpContextToken<T>): T {
+    if (!this.map.has(token)) {
+      this.map.set(token, token.defaultValue());
+    }
+    return this.map.get(token) as T;
+  }
+
+  /**
+   * Delete the value associated with the given token.
+   *
+   * @param token The reference to an instance of `HttpContextToken`.
+   *
+   * @returns A reference to itself for easy chaining.
+   */
+  delete(token: HttpContextToken<unknown>): HttpContext {
+    this.map.delete(token);
+    return this;
+  }
+
+  /**
+   * @returns a list of tokens currently stored in the context.
+   */
+  keys(): IterableIterator<HttpContextToken<unknown>> {
+    return this.map.keys();
+  }
+}
\ No newline at end of file
diff --git a/packages/common/http/src/request.ts b/packages/common/http/src/request.ts
index 6f45a5e3e6..bb49113b0a 100644
--- a/packages/common/http/src/request.ts
+++ b/packages/common/http/src/request.ts
@@ -6,9 +6,11 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {HttpContext} from './context';
 import {HttpHeaders} from './headers';
 import {HttpParams} from './params';
 
+
 /**
  * Construction interface for `HttpRequest`s.
  *
@@ -16,6 +18,7 @@ import {HttpParams} from './params';
  */
 interface HttpRequestInit {
   headers?: HttpHeaders;
+  context?: HttpContext;
   reportProgress?: boolean;
   params?: HttpParams;
   responseType?: 'arraybuffer'|'blob'|'json'|'text';
@@ -91,6 +94,11 @@ export class HttpRequest<T> {
   // TODO(issue/24571): remove '!'.
   readonly headers!: HttpHeaders;
 
+  /**
+   * Shared and mutable context that can be used by interceptors
+   */
+  readonly context!: HttpContext;
+
   /**
    * Whether this request should be made in a way that exposes progress events.
    *
@@ -137,6 +145,7 @@ export class HttpRequest<T> {
 
   constructor(method: 'DELETE'|'GET'|'HEAD'|'JSONP'|'OPTIONS', url: string, init?: {
     headers?: HttpHeaders,
+    context?: HttpContext,
     reportProgress?: boolean,
     params?: HttpParams,
     responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -144,6 +153,7 @@ export class HttpRequest<T> {
   });
   constructor(method: 'POST'|'PUT'|'PATCH', url: string, body: T|null, init?: {
     headers?: HttpHeaders,
+    context?: HttpContext,
     reportProgress?: boolean,
     params?: HttpParams,
     responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -151,6 +161,7 @@ export class HttpRequest<T> {
   });
   constructor(method: string, url: string, body: T|null, init?: {
     headers?: HttpHeaders,
+    context?: HttpContext,
     reportProgress?: boolean,
     params?: HttpParams,
     responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -159,6 +170,7 @@ export class HttpRequest<T> {
   constructor(
       method: string, readonly url: string, third?: T|{
         headers?: HttpHeaders,
+        context?: HttpContext,
         reportProgress?: boolean,
         params?: HttpParams,
         responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -166,6 +178,7 @@ export class HttpRequest<T> {
       }|null,
       fourth?: {
         headers?: HttpHeaders,
+        context?: HttpContext,
         reportProgress?: boolean,
         params?: HttpParams,
         responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -203,6 +216,10 @@ export class HttpRequest<T> {
         this.headers = options.headers;
       }
 
+      if (!!options.context) {
+        this.context = options.context;
+      }
+
       if (!!options.params) {
         this.params = options.params;
       }
@@ -213,6 +230,11 @@ export class HttpRequest<T> {
       this.headers = new HttpHeaders();
     }
 
+    // If no context have been passed in, construct a new HttpContext instance.
+    if (!this.context) {
+      this.context = new HttpContext();
+    }
+
     // If no parameters have been passed in, construct a new HttpUrlEncodedParams instance.
     if (!this.params) {
       this.params = new HttpParams();
@@ -312,6 +334,7 @@ export class HttpRequest<T> {
   clone(): HttpRequest<T>;
   clone(update: {
     headers?: HttpHeaders,
+    context?: HttpContext,
     reportProgress?: boolean,
     params?: HttpParams,
     responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -324,6 +347,7 @@ export class HttpRequest<T> {
   }): HttpRequest<T>;
   clone<V>(update: {
     headers?: HttpHeaders,
+    context?: HttpContext,
     reportProgress?: boolean,
     params?: HttpParams,
     responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -336,6 +360,7 @@ export class HttpRequest<T> {
   }): HttpRequest<V>;
   clone(update: {
     headers?: HttpHeaders,
+    context?: HttpContext,
     reportProgress?: boolean,
     params?: HttpParams,
     responseType?: 'arraybuffer'|'blob'|'json'|'text',
@@ -370,6 +395,9 @@ export class HttpRequest<T> {
     let headers = update.headers || this.headers;
     let params = update.params || this.params;
 
+    // Pass on context if needed
+    const context = update.context ?? this.context;
+
     // Check whether the caller has asked to add headers.
     if (update.setHeaders !== undefined) {
       // Set every requested header.
@@ -389,6 +417,7 @@ export class HttpRequest<T> {
     return new HttpRequest(method, url, body, {
       params,
       headers,
+      context,
       reportProgress,
       responseType,
       withCredentials,
diff --git a/packages/common/http/test/context_spec.ts b/packages/common/http/test/context_spec.ts
new file mode 100644
index 0000000000..e85c916f3a
--- /dev/null
+++ b/packages/common/http/test/context_spec.ts
@@ -0,0 +1,59 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {HttpContext, HttpContextToken} from '../src/context';
+
+const IS_ENABLED = new HttpContextToken<boolean>(() => false);
+const CACHE_OPTION =
+    new HttpContextToken<{cache: boolean, expiresIn?: number}>(() => ({cache: false}));
+
+describe('HttpContext', () => {
+  let context: HttpContext;
+
+  beforeEach(() => {
+    context = new HttpContext();
+  });
+
+  describe('with basic value', () => {
+    it('should test public api', () => {
+      expect(context.get(IS_ENABLED)).toBe(false);
+      expect([...context.keys()]).toEqual([
+        IS_ENABLED
+      ]);  // value from factory function is stored in the map upon access
+
+      context.set(IS_ENABLED, true);
+      expect(context.get(IS_ENABLED)).toBe(true);
+      expect([...context.keys()]).toEqual([IS_ENABLED]);
+
+      context.delete(IS_ENABLED);
+      expect([...context.keys()]).toEqual([]);
+    });
+  });
+
+  describe('with complex value', () => {
+    it('should test public api', () => {
+      expect(context.get(CACHE_OPTION)).toEqual({cache: false});
+      expect([...context.keys()]).toEqual([CACHE_OPTION]);
+
+      const value = {cache: true, expiresIn: 30};
+      context.set(CACHE_OPTION, value);
+      expect(context.get(CACHE_OPTION)).toBe(value);
+      expect([...context.keys()]).toEqual([CACHE_OPTION]);
+
+      context.delete(CACHE_OPTION);
+      expect([...context.keys()]).toEqual([]);
+    });
+
+    it('should ensure that same reference is returned for default value between multiple accesses',
+       () => {
+         const value = context.get(CACHE_OPTION);  // will get default value
+         expect(value).toEqual({cache: false});
+         expect(context.get(CACHE_OPTION)).toBe(value);
+       });
+  });
+});
diff --git a/packages/common/http/test/module_spec.ts b/packages/common/http/test/module_spec.ts
index b242d21da9..ef8a866be9 100644
--- a/packages/common/http/test/module_spec.ts
+++ b/packages/common/http/test/module_spec.ts
@@ -8,6 +8,7 @@
 
 import {HttpHandler} from '@angular/common/http/src/backend';
 import {HttpClient} from '@angular/common/http/src/client';
+import {HttpContext, HttpContextToken} from '@angular/common/http/src/context';
 import {HTTP_INTERCEPTORS, HttpInterceptor} from '@angular/common/http/src/interceptor';
 import {HttpRequest} from '@angular/common/http/src/request';
 import {HttpEvent, HttpResponse} from '@angular/common/http/src/response';
@@ -19,6 +20,8 @@ import {TestBed} from '@angular/core/testing';
 import {Observable} from 'rxjs';
 import {map} from 'rxjs/operators';
 
+const IS_INTERCEPTOR_C_ENABLED = new HttpContextToken<boolean|undefined>(() => undefined);
+
 class TestInterceptor implements HttpInterceptor {
   constructor(private value: string) {}
 
@@ -49,6 +52,19 @@ class InterceptorB extends TestInterceptor {
   }
 }
 
+class InterceptorC extends TestInterceptor {
+  constructor() {
+    super('C');
+  }
+
+  intercept(req: HttpRequest<any>, delegate: HttpHandler): Observable<HttpEvent<any>> {
+    if (req.context.get(IS_INTERCEPTOR_C_ENABLED) === true) {
+      return super.intercept(req, delegate);
+    }
+    return delegate.handle(req);
+  }
+}
+
 @Injectable()
 class ReentrantInterceptor implements HttpInterceptor {
   constructor(private client: HttpClient) {}
@@ -58,54 +74,66 @@ class ReentrantInterceptor implements HttpInterceptor {
   }
 }
 
-{
-  describe('HttpClientModule', () => {
-    let injector: Injector;
-    beforeEach(() => {
-      injector = TestBed.configureTestingModule({
-        imports: [HttpClientTestingModule],
-        providers: [
-          {provide: HTTP_INTERCEPTORS, useClass: InterceptorA, multi: true},
-          {provide: HTTP_INTERCEPTORS, useClass: InterceptorB, multi: true},
-        ],
-      });
-    });
-    it('initializes HttpClient properly', done => {
-      injector.get(HttpClient).get('/test', {responseType: 'text'}).subscribe((value: string) => {
-        expect(value).toBe('ok!');
-        done();
-      });
-      injector.get(HttpTestingController).expectOne('/test').flush('ok!');
-    });
-    it('intercepts outbound responses in the order in which interceptors were bound', done => {
-      injector.get(HttpClient)
-          .get('/test', {observe: 'response', responseType: 'text'})
-          .subscribe(() => done());
-      const req = injector.get(HttpTestingController).expectOne('/test') as TestRequest;
-      expect(req.request.headers.get('Intercepted')).toEqual('A,B');
-      req.flush('ok!');
-    });
-    it('intercepts inbound responses in the right (reverse binding) order', done => {
-      injector.get(HttpClient)
-          .get('/test', {observe: 'response', responseType: 'text'})
-          .subscribe((value: HttpResponse<string>) => {
-            expect(value.headers.get('Intercepted')).toEqual('B,A');
-            done();
-          });
-      injector.get(HttpTestingController).expectOne('/test').flush('ok!');
-    });
-    it('allows interceptors to inject HttpClient', done => {
-      TestBed.resetTestingModule();
-      injector = TestBed.configureTestingModule({
-        imports: [HttpClientTestingModule],
-        providers: [
-          {provide: HTTP_INTERCEPTORS, useClass: ReentrantInterceptor, multi: true},
-        ],
-      });
-      injector.get(HttpClient).get('/test').subscribe(() => {
-        done();
-      });
-      injector.get(HttpTestingController).expectOne('/test').flush('ok!');
+describe('HttpClientModule', () => {
+  let injector: Injector;
+  beforeEach(() => {
+    injector = TestBed.configureTestingModule({
+      imports: [HttpClientTestingModule],
+      providers: [
+        {provide: HTTP_INTERCEPTORS, useClass: InterceptorA, multi: true},
+        {provide: HTTP_INTERCEPTORS, useClass: InterceptorB, multi: true},
+        {provide: HTTP_INTERCEPTORS, useClass: InterceptorC, multi: true},
+      ],
     });
   });
-}
+  it('initializes HttpClient properly', done => {
+    injector.get(HttpClient).get('/test', {responseType: 'text'}).subscribe((value: string) => {
+      expect(value).toBe('ok!');
+      done();
+    });
+    injector.get(HttpTestingController).expectOne('/test').flush('ok!');
+  });
+  it('intercepts outbound responses in the order in which interceptors were bound', done => {
+    injector.get(HttpClient)
+        .get('/test', {observe: 'response', responseType: 'text'})
+        .subscribe(() => done());
+    const req = injector.get(HttpTestingController).expectOne('/test') as TestRequest;
+    expect(req.request.headers.get('Intercepted')).toEqual('A,B');
+    req.flush('ok!');
+  });
+  it('intercepts outbound responses in the order in which interceptors were bound and include specifically enabled interceptor',
+     done => {
+       injector.get(HttpClient)
+           .get('/test', {
+             observe: 'response',
+             responseType: 'text',
+             context: new HttpContext().set(IS_INTERCEPTOR_C_ENABLED, true)
+           })
+           .subscribe(value => done());
+       const req = injector.get(HttpTestingController).expectOne('/test') as TestRequest;
+       expect(req.request.headers.get('Intercepted')).toEqual('A,B,C');
+       req.flush('ok!');
+     });
+  it('intercepts inbound responses in the right (reverse binding) order', done => {
+    injector.get(HttpClient)
+        .get('/test', {observe: 'response', responseType: 'text'})
+        .subscribe((value: HttpResponse<string>) => {
+          expect(value.headers.get('Intercepted')).toEqual('B,A');
+          done();
+        });
+    injector.get(HttpTestingController).expectOne('/test').flush('ok!');
+  });
+  it('allows interceptors to inject HttpClient', done => {
+    TestBed.resetTestingModule();
+    injector = TestBed.configureTestingModule({
+      imports: [HttpClientTestingModule],
+      providers: [
+        {provide: HTTP_INTERCEPTORS, useClass: ReentrantInterceptor, multi: true},
+      ],
+    });
+    injector.get(HttpClient).get('/test').subscribe(() => {
+      done();
+    });
+    injector.get(HttpTestingController).expectOne('/test').flush('ok!');
+  });
+});
diff --git a/packages/common/http/test/request_spec.ts b/packages/common/http/test/request_spec.ts
index 560de46513..7519b47e00 100644
--- a/packages/common/http/test/request_spec.ts
+++ b/packages/common/http/test/request_spec.ts
@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {HttpContext} from '@angular/common/http/src/context';
 import {HttpHeaders} from '@angular/common/http/src/headers';
 import {HttpParams} from '@angular/common/http/src/params';
 import {HttpRequest} from '@angular/common/http/src/request';
@@ -56,6 +57,11 @@ const TEST_STRING = `I'm a body!`;
         const req = new HttpRequest('GET', TEST_URL, {headers});
         expect(req.headers).toBe(headers);
       });
+      it('uses the provided context if passed', () => {
+        const context = new HttpContext();
+        const req = new HttpRequest('GET', TEST_URL, {context});
+        expect(req.context).toBe(context);
+      });
       it('defaults to Json', () => {
         const req = new HttpRequest('GET', TEST_URL);
         expect(req.responseType).toBe('json');
@@ -65,8 +71,10 @@ const TEST_STRING = `I'm a body!`;
       const headers = new HttpHeaders({
         'Test': 'Test header',
       });
+      const context = new HttpContext();
       const req = new HttpRequest('POST', TEST_URL, 'test body', {
         headers,
+        context,
         reportProgress: true,
         responseType: 'text',
         withCredentials: true,
@@ -79,6 +87,8 @@ const TEST_STRING = `I'm a body!`;
         // Headers should be the same, as the headers are sealed.
         expect(clone.headers).toBe(headers);
         expect(clone.headers.get('Test')).toBe('Test header');
+
+        expect(clone.context).toBe(context);
       });
       it('and updates the url', () => {
         expect(req.clone({url: '/changed'}).url).toBe('/changed');
@@ -89,6 +99,10 @@ const TEST_STRING = `I'm a body!`;
       it('and updates the body', () => {
         expect(req.clone({body: 'changed body'}).body).toBe('changed body');
       });
+      it('and updates the context', () => {
+        const newContext = new HttpContext();
+        expect(req.clone({context: newContext}).context).toBe(newContext);
+      });
     });
     describe('content type detection', () => {
       const baseReq = new HttpRequest('POST', '/test', null);