Posting form-urlencoded in Angular 5

Question

I'm trying to develop an application using a Spring backend and an Angular 5 frontend. For the login I am using Spring Security and in the frontend I am trying to post the login data as x-www-form-urlencoded. However the backend receives null for both username and password. The Angular 5 documentation for HttpClient provides examples only for posting json data and Http became deprecated.

Any suggestions on how to fix this would be greatly appreciated.

Here is my Angular code:

constructor(public httpClient: HttpClient) {
    console.log('Hello RestService Provider');
}

login(username: string, password: string) {
    var body = 'username=' + username + '&password=' + password + "&remember-me=" +  false;
    var headers = new HttpHeaders();
    headers.append('Content-Type', 'application/x-www-form-urlencoded; charset=utf-8');
    let options = {headers: headers, withCredentials: true};
    this.callPostWithOptions("login", body, options).then(data=>{
      this.getCurrentUser();
    });
}

callPostWithOptions(address, body, options) {
    return new Promise(resolve => {
      address = this._SERVER_HOST + ":" + this._SERVER_PORT + "/" + address;
      this.httpClient.post(address, body, options)
        .subscribe((data) => {
            resolve(data);
          },
          (err) => {
            console.log("error during POST", err)
          });
    });
}

And the server endpoint:

@RequestMapping(value = "/login", method = RequestMethod.GET)
@CrossOrigin(origins = "*")
public ModelAndView handle() {
    return new ModelAndView("/app/userOverview");
}

Edit: I forgot to mention, when I test it with Postman it works without a problem

Answer 1

The new HTTPClient module only works with immutable types. This means that headers and params cannot be modified. The append() operation actually returns a copy of your original, with the added header.

let headers = new HttpHeaders();
headers.append('...','...');// <- doesn't change the original object, but creates a new one!

Instead, you want to capture the returned object:

let headers = new HttpHeaders();
headers = headers.append('...','...');

As a sidenote, I would change callPostWithOptions to use the toPromise() operator:

callPostWithOptions(address, body, options) {
   address = '...';
   return this.httpClient.post(address, body, options).toPromise();
}