Skip to main content
Version: 5.1.1

Token Swap

This way uses server-side code or at least access to an exchange server, otherwise, compared to other methods, it is impossible to use.

With this approach, you provide the URI/URL to your desired exchange server to perform all necessary requests to Spotify, as well as requests that return back to the "server URI".

The exchange server must be able to:

  • Return the authorization code from Spotify API authenticate page via GET request to the "server URI".
  • Request the token response object via POST to the Spotify API token page.
  • Request a refreshed token response object via POST to the Spotify API token page.

The good news is that you do not need to code it yourself.

The advantages of this method are that the client ID and redirect URI are very well hidden and almost unexposed, but more importantly, your client secret is never exposed and is completely hidden compared to other methods (excluding ImplicitGrantAuth as it does not deal with a client secret). This means your Spotify app cannot be spoofed by a malicious third party.

Using TokenSwapWebAPIFactory​

The TokenSwapWebAPIFactory will create and configure a SpotifyWebAPI object for you.

It does this through the method GetWebApiAsync asynchronously, which means it will not halt execution of your program while obtaining it for you. If you would like to halt execution, which is synchronous, use GetWebApiAsync().Result without using await.

TokenSwapWebAPIFactory webApiFactory;
SpotifyWebAPI spotify;

// You should store a reference to WebAPIFactory if you are using AutoRefresh or want to manually refresh it later on. New WebAPIFactory objects cannot refresh SpotifyWebAPI object that they did not give to you.
webApiFactory = new TokenSwapWebAPIFactory("INSERT LINK TO YOUR index.php HERE")
{
    Scope = Scope.UserReadPrivate | Scope.UserReadEmail | Scope.PlaylistReadPrivate,
    AutoRefresh = true
};
// You may want to react to being able to use the Spotify service.
// webApiFactory.OnAuthSuccess += (sender, e) => authorized = true;
// You may want to react to your user's access expiring.
// webApiFactory.OnAccessTokenExpired += (sender, e) => authorized = false;

try
{
    spotify = await webApiFactory.GetWebApiAsync();
    // Synchronous way:
    // spotify = webApiFactory.GetWebApiAsync().Result;
}
catch (Exception ex)
{
    // Example way to handle error reporting gracefully with your SpotifyWebAPI wrapper
    // UpdateStatus($"Spotify failed to load: {ex.Message}");
}

Using TokenSwapAuth​

Since the TokenSwapWebAPIFactory not only simplifies the whole process but offers additional functionality too (such as AutoRefresh and AuthSuccess AuthFailure events), use of this way is very verbose and is only recommended if you are having issues with TokenSwapWebAPIFactory or need access to the tokens.

TokenSwapAuth auth = new TokenSwapAuth(
    exchangeServerUri: "INSERT LINK TO YOUR index.php HERE",
    serverUri: "http://localhost:4002",
    scope: Scope.UserReadPrivate | Scope.UserReadEmail | Scope.PlaylistReadPrivate
);
auth.AuthReceived += async (sender, response) =>
{
    lastToken = await auth.ExchangeCodeAsync(response.Code);

    spotify = new SpotifyWebAPI()
    {
        TokenType = lastToken.TokenType,
        AccessToken = lastToken.AccessToken
    };

    authenticated = true;
    auth.Stop();
};
auth.OnAccessTokenExpired += async (sender, e) => spotify.AccessToken = (await auth.RefreshAuthAsync(lastToken.RefreshToken)).AccessToken;
auth.Start();
auth.OpenBrowser();

Token Swap Endpoint​

To keep your client secret completely secure and your client ID and redirect URI as secure as possible, use of a web server (such as a php website) is required.

To use this method, an external HTTP Server (that you may need to create) needs to be able to supply the following HTTP Endpoints to your application:

/swap - Swaps out an authorization_code with an access_token and refresh_token - The following parameters are required in the JSON POST Body:

  • grant_type (set to "authorization_code")
  • code (the authorization_code)
  • redirect_uri

/refresh - Refreshes an access_token - The following parameters are required in the JSON POST Body:

  • grant_type (set to "refresh_token")
  • refresh_token

The following open-source token swap endpoint code can be used for your website:

Remarks​

It should be noted that GitHub Pages does not support hosting php scripts. Hosting php scripts through it will cause the php to render as plain HTML, potentially compromising your client secret while doing absolutely nothing.

Be sure you have whitelisted your redirect uri in the Spotify Developer Dashboard otherwise the authorization will always fail.

If you did not use the WebAPIFactory or you provided a serverUri different from its default, you must make sure your redirect uri's script at your endpoint will properly redirect to your serverUri (such as changing the areas which refer to localhost:4002 if you had changed serverUri from its default), otherwise it will never reach your new serverUri.