💾 feat: Production-ready Memory Store for express-session

[lkiesow]

The express-session library comes with a session storage meant for testing by default. That is why you get a message like this when you start up LibreChat with OIDC enabled:

Warning: connect.session() MemoryStore is not
designed for a production environment, as it will leak
memory, and will not scale past a single process.

LibreChat can already use Redis as a session storage, although Redis support is still marked as experimental. It also makes the set-up more complex, since you will need to configure and run yet another service.

This pull request provides a simple alternative by using a in-memory session store marked as a production-ready alternative by the guys from express-session¹. You can still configure Redis, but this provides a simple, good default for everyone else.

See also #1014

¹⁾ https://github.com/expressjs/session?tab=readme-ov-file#compatible-session-stores

Change Type

Please delete any irrelevant options.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Translation update

Testing

• Configure OIDC
• Running without this patch: You should see the memry leak warning from above
• Running with this patch applied: No warning should show up
• In any case, the login via OIDC should still work

[dennis531]

We have the problem that the session is undefined sometimes. I found a similar problem on https://stackoverflow.com/questions/63259184/node-with-express-session-issue but there is no working solution. It seems to be a race condition. I hope the new memory store solves this problem.

Logs

LibreChat | Error: did not find expected authorization request details in session, req.session["oidc:studip.de"] is undefined
LibreChat | at /app/node_modules/openid-client/lib/passport_strategy.js:132:13
LibreChat | at OpenIDConnectStrategy.authenticate (/app/node_modules/openid-client/lib/passport_strategy.js:191:5)
LibreChat | at attempt (/app/node_modules/passport/lib/middleware/authenticate.js:369:16)
LibreChat | at authenticate (/app/node_modules/passport/lib/middleware/authenticate.js:370:7)
LibreChat | at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
LibreChat | at next (/app/node_modules/express/lib/router/route.js:149:13)
LibreChat | at Route.dispatch (/app/node_modules/express/lib/router/route.js:119:3)
LibreChat | at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
LibreChat | at /app/node_modules/express/lib/router/index.js:284:15
LibreChat | at Function.process_params (/app/node_modules/express/lib/router/index.js:346:12)