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
Unlike in the browser, on the server there is no concept of a document origin.
Thus, it is illegal to make requests for relative URLs against Http on platform-server.
Currently this fails with a vague error:
Error: Uncaught (in promise): Error at resolvePromise
This change adds explicit validation and a friendlier error message:
Error: URLs requested via Http on the server must be absolute. URL: /testing
Another option considered was to track the concept of an origin for the platform
and automatically prepend it to relative URLs. This would cause automatic "local
RPCs" to be made, though, which would be an unexpected and undesirable default
behavior.
Fixes#15349
PR Close#15357
Victor Berchet
tinayuangao
Alex Rickabaugh
Miško Hevery
Jason Aden