angular - HTTPClient POST tries to parse a non-JSON response

Question

I'm trying to make a request in Angular and I know that the HTTP response will not be in JSON but in text. However, Angular seems to be expecting a JSON response since the error is the following:

SyntaxError: Unexpected token < in JSON at position 0 at JSON.parse () at XMLHttpRequest.c

As well as

Http failure during parsing for http://localhost:9...

This is the post method:

return this.http.post(this.loginUrl, this.createLoginFormData(username, password), this.httpOptions)
  .pipe(
    tap( // Log the result or error
      data => console.log(data);
      error => console.log(error)
    )
  );

and the headers.

private httpOptions = {

  headers: new HttpHeaders({
    'Accept': 'text/html, application/xhtml+xml, */*',
    'Content-Type': 'application/x-www-form-urlencoded',
    responseType: 'text'
  },

) };

I thought that responseType: 'text' would be enough to make Angular expect a non JSON response.

Answer 1

You've put responseType: 'text' in the wrong section of your httpOptions - It should sit outside of headers, like so:

private httpOptions = {
  headers: new HttpHeaders({
    'Accept': 'text/html, application/xhtml+xml, */*',
    'Content-Type': 'application/x-www-form-urlencoded'
  }),
  responseType: 'text'
};

With what you had before, a request header of responseType was being sent to the server, rather than simply having an instruction to Angular to actually treat the response as text.