Angular 6-在应用初始化时接收HTTP GET请求

Question

When my Angular app is started for the first time, meaning right before the web application's pages are returned to the client's browser, I want to extract some information from the HTTP request that requested the app in the first place.

Specifically, I want to access the headers of the HTTP request that called the angular app, from inside the angular app.

Is there anyway to do this in Angular 6?

Thanks

Answer 1

You can create a service that intercept the request implements the HttpInterceptor interface, you can make a clone of the request and push what you want, and then return.

@Injectable() export class RequestInterceptor implements HttpInterceptor {

constructor(private tokenService: TokenService) {}

intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpSentEvent 
    | HttpHeaderResponse | HttpProgressEvent | HttpResponse<any> | HttpUserEvent<any>> {

        if(this.tokenService.hasToken()) {
            const token = this.tokenService.getToken();
            req = req.clone({
                setHeaders: {
                    'x-access-token': token
                }
            });
        }
        return next.handle(req);
}

Don't forget to declare the service in a module:

providers: [{ provide: HTTP_INTERCEPTORS, useClass: RequestInterceptor, multi: true }]