backend-layer

backend-layer

The Python FastAPI backend layer for RepoForge Web, handling HTTP routing, middleware, authentication, rate limiting, and database migrations. Owns all server-side request processing and API endpoints.

Trigger: When working in backend/ directory — adding routes, modifying middleware, debugging authentication, or extending API endpoints.

Quick Reference

Critical Patterns (Summary)

• Middleware Chain: FastAPI middleware runs in order — correlation_id → request_logging → security_headers. Each must call call_next to pass control.
• Settings Fail-Fast: Settings from config.py validates required env vars on startup; missing vars cause immediate exit.

Critical Patterns (Detailed)

Middleware Chain

FastAPI middleware executes in declaration order. Each handler must invoke call_next to forward the request; omitting this breaks the chain and returns 500 errors.

@app.middleware("http")
async def security_headers_middleware(request: Request, call_next):  # noqa: ANN001
    response = await call_next(request)
    response.headers["X-Content-Type-Options"] = "nosniff"
    return response

Settings Fail-Fast

from apps.server.app.config import Settings