Is it possible to use the Spotify Web API to write

Question

I would like to write a simple desktop application for personal use that uses the Spotify Web API to build playlists.

As far as I can tell, however, there's no way to use the API without providing a callback URI, which I don't have, seeing as I don't have a domain or server of any kind (other than my personal computer).

Is there a way to use the API without a URI?

If not, what is the best way to set up a callback URI? I don't have much of any experience working with web applications or client / server stuff, and the APIs I've used in the past haven't required any kind of callback.

Answer 1

Some background first, this answer became a bit longer than what I anticipated.

You need an access token. There are three ways to retrieve an access token; Authentication Code flow, Client Credentials flow, and Implicit Grant flow. These are all part of the oAuth 2.0 specification, each with its own purpose.

Since you're going to modify a user's account, you need that user's permission. Now, if you didn't do any actions that required user permissions, you could've used the Client Credentials flow. That's probably the easiest flow to learn since it just requires a request from your server to Spotify's server, and the response contains an access token. No callback/redirect URI is necessary.

As I'm sure you've read, the Authentication Code flow and Implicit Grant flow both require a callback URI. This is because a flow that includes a user, and the callback URI is where Spotify redirects the user after they have entered their password on Spotify's site.

The Authentication Code flow and Implicit Grant flow has benefits and drawbacks. Access tokens retrieved through the Authentication Code flow can be refreshed, but both return tokens that are valid for one hour. This means that a user that's authenticating using the Implicit Grant flow must reauthenticate after an hour. However, the Authentication Code flow does require some backend work, since it needs to make a request to exchange a code given from Spotify's server for an access token. The Implicit Grant flow is more straight forward - you get the access token and off you go.

The callback URI can be a localhost address, so if your desktop application would spin up a web server locally you could handle the callback on the same machine that the application is running on. (It's probably a good idea to not run the web server on port 80 since that might be used by something else.)

There's skeleton code for each of this authentication flows available on Github, see web-api-auth-examples. Read more about the flows in our Authorization Guide. If you choose to run a web server on the user's machine, I recommend that you use the Implicit Grant flow since that doesn't include any server-to-server requests, so you won't have to expose your client_secret exposed in the code. (As opposed to the Authorization Code flow.)

Also, since you're coding in Python, I recommend that you have a look at spotipy, a wrapper around the Web API packed with convenient methods that'll save you some time. If you do go ahead with the Implicit Grant flow, you should have a look at spotify-web-api-js, which has a similar purpose. Note that these wrappers are not at all required to work with the Web API but they'll make your life easier.