For angular 1.x, write an Interceptor:
For purposes of global error handling, authentication, or any kind of
synchronous or asynchronous pre-processing of request or
postprocessing of responses, it is desirable to be able to intercept
requests before they are handed to the server and responses before
they are handed over to the application code that initiated these
requests
For angular 2.x / 4.x, RequestOptions should be the key to solve your problem. Set base url for angular 2 http requests
I'm using angular2, my solution is create a Service
and inject "Http" dependency, then write two methods "get", "post", these methods add an entry to header before calling "Http", in other component / service, I just inject this Service
class, then call its "get" or "post".