Anyone tried to integrate dropbox in unity?

@TwistedSage - don't if you're still looking for an answer, but given that a few people have been asking if you got this to work I thought I'd place a a possible solution here.

Given that you're encountering an error 500 when trying to exchange the OAuth 2 key for an access token, it's possible that the issue may be with how you're making the request to Dropbox's API. A 500 error typically indicates that something went wrong on the server side, but this could also be due to the server not understanding the request.

You could exchange the OAuth 2 authorization code for an access token in Unity using the UnityWebRequest class (warning untested):

 string authorizationCode = "<Your Authorization Code>";
 string clientId = "<Your Client ID>";
 string clientSecret = "<Your Client Secret>";
 string redirectUri = "<Your Redirect URI>";
 
 Dictionary<string, string> headers = new Dictionary<string, string>();
 headers.Add("Content-Type", "application/x-www-form-urlencoded");
 headers.Add("Authorization", "Basic " + System.Convert.ToBase64String(System.Text.Encoding.ASCII.GetBytes(clientId + ":" + clientSecret)));
 
 WWWForm form = new WWWForm();
 form.AddField("code", authorizationCode);
 form.AddField("grant_type", "authorization_code");
 form.AddField("redirect_uri", redirectUri);
 
 UnityWebRequest www = UnityWebRequest.Post("https://api.dropbox.com/1/oauth2/token", form.data, headers);
 yield return www.SendWebRequest();
 
 if (www.isNetworkError || www.isHttpError)
 {
     Debug.Log(www.error);
 }
 else
 {
     Debug.Log("Access Token: " + www.downloadHandler.text);
 }

This script is attempting to POST the request to Dropbox's token endpoint with the appropriate headers and body parameters.

If the issue persists, post the error response body here to provide some additional information that might help pinpoint the problem. It could be that the OAuth 2 key is not valid or that the request body is not formatted correctly.