Angular HttpInterceptor for Headers

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The HeaderInterceptor helps intercept HTTP requests and responses. It initializes an HttpRequest with the headers of the request and a clone of the headers. It returns an Observable that is emitted when the handle method is called on the next HttpHandler .

The handle method takes an HttpHandler as a parameter. The handler is executed when the Observable is emitted by the HeaderInterceptor . The handler can access the req object, which contains the HttpRequest that was intercepted. The authReq object is a copy of the headers of the request that was intercepted.

Library: angular

Shortcut: a_http_interceptor_headers

import { Injectable } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable()
export class HeaderInterceptor implements HttpInterceptor {
  constructor() {}

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const headers = req.headers
      .set('Content-Type', 'application/json');
    const authReq = req.clone({ headers });
    return next.handle(authReq);
  }
}