[OpsAI] Fix unhandled KeyError in /user/<username> route -> return 404

[mw-middleware-labs-sandbox]

Root Cause

The GET /user/<username> route in flask/app.py (user_profile function) accessed the in-memory user_data dict via unguarded user_data[username]. When the requested username did not exist (e.g. user7), this raised an unhandled KeyError, resulting in an HTTP 500 error instead of a proper client-facing 404.

This was confirmed via trace data showing deterministic 500 responses for /user/user7 requests, with the stack trace pointing to app.py line 78 in user_profile.

Fix

• Replaced user_data[username] with user_data.get(username).
• Added a check: if the lookup returns None, call abort(404, description=f"User '{username}' not found").
• Added abort to the Flask imports.

Test Cases

• GET /user/user1 -> 200 (unchanged behavior for existing users)
• GET /user/user7 -> 404 with descriptive message (previously 500 with unhandled KeyError)

---

OpsAI Context

Open OpsAI Chat: Open Chat

Created By

Name: Sandbox
Email: sandbox@middleware.io