Example
import { Http, Request, RequestOptionsArgs, Response, RequestOptions, ConnectionBackend, Headers } from '@angular/http';
import { Router } from '@angular/router';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/empty';
import 'rxjs/add/observable/throw';
import 'rxjs/add/operator/catch';
import { ApplicationConfiguration } from '../application-configuration/application-configuration';
/**
* This class extends the Http class from angular and adds automaticaly the server URL(if in development mode) and 2 headers by default:
* Headers added: 'Content-Type' and 'X-AUTH-TOKEN'.
* 'Content-Type' can be set in any othe service, and if set, it will NOT be overwritten in this class any more.
*/
export class HttpServiceLayer extends Http {
constructor(backend: ConnectionBackend, defaultOptions: RequestOptions, private _router: Router, private appConfig: ApplicationConfiguration) {
super(backend, defaultOptions);
}
request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
this.getRequestOptionArgs(options);
return this.intercept(super.request(this.appConfig.getServerAdress() + url, options));
}
/**
* This method checks if there are any headers added and if not created the headers map and ads 'Content-Type' and 'X-AUTH-TOKEN'
* 'Content-Type' is not overwritten if it is allready available in the headers map
*/
getRequestOptionArgs(options?: RequestOptionsArgs): RequestOptionsArgs {
if (options == null) {
options = new RequestOptions();
}
if (options.headers == null) {
options.headers = new Headers();
}
if (!options.headers.get('Content-Type')) {
options.headers.append('Content-Type', 'application/json');
}
if (this.appConfig.getAuthToken() != null) {
options.headers.append('X-AUTH-TOKEN', this.appConfig.getAuthToken());
}
return options;
}
/**
* This method as the name sugests intercepts the request and checks if there are any errors.
* If an error is present it will be checked what error there is and if it is a general one then it will be handled here, otherwise, will be
* thrown up in the service layers
*/
intercept(observable: Observable<Response>): Observable<Response> {
// return observable;
return observable.catch((err, source) => {
if (err.status == 401) {
this._router.navigate(['/login']);
//return observable;
return Observable.empty();
} else {
//return observable;
return Observable.throw(err);
}
});
}
}
