android - volley error No authentication challenges found

Question

I am trying to work with some legacy code and have come up against an issue when using volley.

I am trying to get to an api that our main site has and it works fine

Answer 1

This error happens because the server sends a 401 (Unauthorized) but does not give a "WWW-Authenticate" which is a hint for the client what to do next. The "WWW-Authenticate" Header tells the client which kind of authentication is needed (either Basic or Digest). This is usually not very useful in headless http clients, but that's how the standard is defined. The error occurs because the lib tries to parse the "WWW-Authenticate" header but can't.

Possible solutions if you can change the server:

• Add a fake "WWW-Authenticate" header like: WWW-Authenticate: Basic realm="fake". This is a mere workaround not a solution, but it should work and the http client is satisfied.
• Use HTTP status code 403 instead of 401. It's semantic is not the same and usually when working with login 401 is a correct response (see here for a detailed discussion) but its close enough.

Possible solutions if you can't change the server:

As @ErikZ wrote in his post you could use a try&catch

HttpURLConnection connection = ...;
try {
    // Will throw IOException if server responds with 401.
    connection.getResponseCode(); 
} catch (IOException e) {
    // Will return 401, because now connection has the correct internal state.
    int responsecode = connection.getResponseCode(); 
}

I also posted this here: java.io.IOException : No authentication challenges found