Pi Touch HTTP Server

A lightweight Flask-based web server intended for a Raspberry Pi with a touch display. It exposes HTTP endpoints for controlling the display power state, launching a Google Photos Picker session, and a minimal in-memory publish/subscribe message queue.

Features

• Display control: GET /display?cmd=on|off uses xset to toggle the HDMI display.
• Google Photos Picker integration:
  • POST /selectPhotos creates a Picker session, returning a pickerUri the user can open in the Google Photos app or web UI. The backend polls the session for up to 15 minutes, following the Picker API guidance, and caches the selected media.
  • GET /selectPhotos?sessionId=<id> returns the cached status, including any picked media items once available.
  • When a selection completes the server downloads every asset into screensaver/photos/ and rotates a random image on-screen every two minutes using feh, mirroring the original screensaver behavior.
• Publish/Subscribe:
  • POST /publish accepts a JSON payload and enqueues it.
  • GET /subscribe returns and removes the oldest queued message.
• Serves static/index.html when visiting /.

Requirements

• Python 3
• Flask
• requests
• google-auth
• google-auth-oauthlib

Install the Python dependencies with:

pip install flask requests google-auth google-auth-oauthlib

Configuring Google Photos Picker OAuth

1. Create an OAuth 2.0 Client ID (type Desktop) in Google Cloud Console.
2. Download the client configuration JSON and save it as screensaver/credentials.json.
3. Ensure the screensaver/ directory is writable so the app can persist picker_token.json with refreshed tokens.
4. On first run you will be prompted to complete the OAuth flow. The application requests the https://www.googleapis.com/auth/photospicker.mediaitems.readonly scope.

Running

python server.py

The server listens on port 8080 on all interfaces.

Example Picker workflow

The following curl commands demonstrate an end-to-end session using the Picker API.

1. Create a session (optionally constrain the selection with maxItemCount):

   curl -sS -X POST http://<host>:8080/selectPhotos \
        -H 'Content-Type: application/json' \
        -d '{"maxItemCount": 25}'

   A successful response resembles:

   {
     "sessionId": "41b6f2fd-bf22-4242-94e9-1b6f640a2501",
     "pickerUri": "https://photos.google.com/picker/...",
     "status": "PENDING",
     "statusEndpoint": "http://<host>:8080/selectPhotos?sessionId=41b6f2fd-bf22-4242-94e9-1b6f640a2501"
   }

2. Share the pickerUri with the user so they can finish the media selection in the Google Photos app or web UI.

3. Poll for completion (repeat until state becomes COMPLETE or ERROR):

   curl -sS "http://<host>:8080/selectPhotos?sessionId=41b6f2fd-bf22-4242-94e9-1b6f640a2501"

   While pending, the response will include metadata and the recommended polling cadence:

   {
     "sessionId": "41b6f2fd-bf22-4242-94e9-1b6f640a2501",
     "state": "PENDING",
     "pollIntervalSeconds": 5.0,
     "pollingDeadline": "2024-02-21T17:05:42.123456+00:00"
   }

4. Retrieve the selected media once the state becomes COMPLETE:

   curl -sS "http://<host>:8080/selectPhotos?sessionId=41b6f2fd-bf22-4242-94e9-1b6f640a2501" | jq '.mediaItems'

   The array includes every chosen item with its metadata and download URLs returned by Google Photos Picker. The response also lists the files saved within screensaver/photos/, which feed the two-minute slideshow cycle.

5. (Optional) Abort a session if needed by calling:

   curl -sS -X DELETE "https://photospicker.googleapis.com/v1/sessions/41b6f2fd-bf22-4242-94e9-1b6f640a2501"

   The PhotosPickerService automatically stops polling when the session completes or times out, but explicit cleanup can be useful while testing.

License

This project is provided as-is without warranty.