Previously, an interceptor attempting to inject HttpClient directly
would receive a circular dependency error, as HttpClient was
constructed via a factory which injected the interceptor instances.
Users want to inject HttpClient into interceptors to make supporting
requests (ex: to retrieve an authentication token). Currently this is
only possible by injecting the Injector and using it to resolve
HttpClient at request time.
Either HttpClient or the user has to deal specially with the circular
dependency. This change moves that responsibility into HttpClient
itself. By utilizing a new class HttpInterceptingHandler which lazily
loads the set of interceptors at request time, it's possible to inject
HttpClient directly into interceptors as construction of HttpClient no
longer requires the interceptor chain to be constructed.
Fixes#18224.
PR Close#19809
Previously, XhrBackend would call JSON.parse('') if the response body was
empty (a 200 status code with content-length 0). This changes the XhrBackend
to attempt the JSON parse only if the response body is non-empty. Otherwise,
the body is left as null.
Fixes#18680.
Fixes#19413.
Fixes#19502.
Fixes#19555.
PR Close#19958
Previously, HttpClient used the overly clever test "body || null"
to determine when a body parameter was provided. This breaks when
the valid bodies '0' or 'false' are provided.
This change tests directly against 'undefined' to detect the presence
of the body parameter, and thus correctly allows falsy values through.
Fixes#19825.
Fixes#19195.
PR Close#19958
Currently HttpClient sends requests for JSON data with the
XMLHttpRequest.responseType set to 'json'. With this flag, the browser
will attempt to parse the response as JSON, but will return 'null' on
any errors. If the JSON response contains an XSSI-prevention prefix,
this will cause the browser's parsing to fail, which is unrecoverable.
The only compelling reason to use the responseType 'json' is for
performance (especially if the browser offloads JSON parsing to a
separate thread). I'm not aware of any browser which does this currently,
nor of any plans to do so. JSON.parse and responseType 'json' both
end up using the same V8 code path in Chrome to implement the parse.
Thus, this change switches all JSON parsing in HttpClient to use
JSON.parse directly.
Fixes#18396, #18453.
PR Close#18466
Today, constructing a new GET request with headers looks like:
const headers = new HttpHeaders({
'My-Header': 'header value',
});
http.get('/url', {headers}).subscribe(...);
This indirection is unnecessary. It'd be more ergonomic to write:
http.get('/url', {headers: {'My-Header': 'header value'}}).subscribe(...);
This commit allows that new syntax, both for HttpHeaders and HttpParams.
In the HttpParams case it also allows construction of HttpParams with a map.
PR Close#18490
HttpClient is an evolution of the existing Angular HTTP API, which exists
alongside of it in a separate package, @angular/common/http. This structure
ensures that existing codebases can slowly migrate to the new API.
The new API improves significantly on the ergonomics and features of the legacy
API. A partial list of new features includes:
* Typed, synchronous response body access, including support for JSON body types
* JSON is an assumed default and no longer needs to be explicitly parsed
* Interceptors allow middleware logic to be inserted into the pipeline
* Immutable request/response objects
* Progress events for both request upload and response download
* Post-request verification & flush based testing framework
Igor Minar
Alex Rickabaugh
Misko Hevery
Yuan Gao
Victor Berchet
jnizet