This is an implementation of the server component for the Apollo Spotify player that implements streaming on the Apple Watch.

Special thanks to @KhaosT for making this player available as open source and to @rafaelmaeuer for pointing me in the right direction for the server implementation.

To run this, you'll need to have Google Cloud Functions configured.

You'll need to have a Spotify app registered at https://developer.spotify.com/dashboard/applications.

Enter open-apollo://callback under "Redirect URIs" and app.awas.Apollo under "Bundle IDs".

Note your client ID and secret, you'll need it below.

Set the following environment variables: SPOTIFY_CLIENT_ID, SPOTIFY_CLIENT_SECRET.

Select a nearby region to keep latency low, replacing $REGION below:

gcloud config set functions/region $REGION

The replace statement in the go.mod file doesn't seem to work with the way Cloud Functions are compiled for deployment, therefore run the following to create a vendor directory:

go mod vendor

Finally, deploy the various endpoints:

# /token
gcloud functions deploy token --entry-point Token --runtime go113 --trigger-http --set-env-vars SPOTIFY_CLIENT_ID=$SPOTIFY_CLIENT_ID,SPOTIFY_CLIENT_SECRET=$SPOTIFY_CLIENT_SECRET

# /refresh
gcloud functions deploy refresh --entry-point Refresh --runtime go113 --trigger-http --set-env-vars SPOTIFY_CLIENT_ID=$SPOTIFY_CLIENT_ID,SPOTIFY_CLIENT_SECRET=$SPOTIFY_CLIENT_SECRET

# /track
gcloud functions deploy track --entry-point Track --runtime go113 --trigger-http

# /tracks
gcloud functions deploy tracks --entry-point Tracks --runtime go113 --trigger-http

# /storage-resolve
gcloud functions deploy storage-resolve --entry-point StorageResolve --runtime go113 --trigger-http

Clone the open-apollo repository.

Copy the base URL for your endpoints (https://$REGION-$PROJECT.cloudfunctions.net/) to the open-apollo/Apollo/Configuration/DefaultServiceConfiguration.swift file, for both YOUR_SERVICE_URL and YOUR_TRACK_SERVICE_URL.

In the open-apollo/Apollo/Configuration/SpotifyAuthorizationContext.swift file, enter your client ID as YOUR_CLIENT_ID, open-apollo as the callbackURLScheme, and open-apollo://callback as the redirect_uri.

In your Apollo Xcode project, in the Info settings for the Apollo target, make sure to add open-apollo as "URL Schemes" in the "URL Types" section.

Compile and run the Apollo app. If you have trouble installing the Apollo Watch app through the iOS Watch app, try running the Watch target directly from Xcode.

If you get any errors, the Cloud Function logs might contain some clues.