431 response when writing

[richjhart]

I'm trying to write to some playlists, and have the required permission and it was even working before.

But suddenly, I'm getting a 431 response (header(s) too long) when trying to add tracks to a playlist.

I can't see anything unusual in my request:
ErrorResponse addTracks = api.AddPlaylistTracks(profile.Id, unsortedPlaylistId, uris);
I've checked and all the variables are exactly as you'd expect.

Has anyone seen this before? I stepped through and couldn't see any unusual headers. The Authorization header looked like a normal length to me.

[richjhart]

Something very odd is going on here. When I step through, and get to the point just before sending, the request looks fine:

When I copy the URL, JSON body, and the two headers (Authorization and Content-Type) over to Postman, it works perfectly in Postman and I get a 201 (Created) response, and I can confirm it has worked.

But if I let the code carry on, I get a 431 response. And as I say, this definitely wasn't happening before! I'm very confused to say the least.

[JohnnyCrazy]

Mh, any error in the body of the response?

[richjhart]

Aha! Figured it out. No error in the body. But basically it happens if too many requests are made.

In SpotifyWebClient.cs, UploadRaw(), is the following code:

        if (headers != null)
        {
            foreach (KeyValuePair<string, string> headerPair in headers)
            {
                _client.DefaultRequestHeaders.TryAddWithoutValidation(headerPair.Key, headerPair.Value);
            }
        }

As far as I can tell, this is adding duplicate headers each call

I just added:
_client.DefaultRequestHeaders.Clear();
and my code is now working. The correct solution would be to check if each header exists and remove it before adding the new one (i.e. replace rather than add). It works on mine because all the requests are the same, so the same headers get added each time. If I get a chance, I'll add a pull request.

[JohnnyCrazy]

Oh, nice catch! 👍

Would really appreciate a PR 😃

[richjhart]

Should be able to do it tomorrow - just don't have the energy to do it tonight

[JohnnyCrazy]

Done by @flownzu , will be released tomorrow in a hotfix, Thanks for reporting @richjhart and thanks for the the fix @flownzu

[richjhart]

Cheers to @flownzu for the fix. Sorry I didn't get around to it myself! (Too many projects, too little time)