first commit

app/middleware.py

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+"""Global exception handlers for the FastAPI application.
+
+Maps AppError subclasses and other exceptions to JSON envelope responses.
+"""
+
+import logging
+import traceback
+
+from fastapi import FastAPI, Request
+from fastapi.exceptions import RequestValidationError
+from fastapi.responses import JSONResponse
+
+from app.exceptions import AppError
+
+logger = logging.getLogger(__name__)
+
+
+def register_exception_handlers(app: FastAPI) -> None:
+    """Register all global exception handlers on the FastAPI app."""
+
+    @app.exception_handler(AppError)
+    async def app_error_handler(_request: Request, exc: AppError) -> JSONResponse:
+        return JSONResponse(
+            status_code=exc.status_code,
+            content={
+                "status": "error",
+                "data": None,
+                "error": exc.message,
+            },
+        )
+
+    @app.exception_handler(RequestValidationError)
+    async def validation_error_handler(
+        _request: Request, exc: RequestValidationError
+    ) -> JSONResponse:
+        details = "; ".join(
+            f"{'.'.join(str(loc) for loc in e['loc'])}: {e['msg']}"
+            for e in exc.errors()
+        )
+        return JSONResponse(
+            status_code=400,
+            content={
+                "status": "error",
+                "data": None,
+                "error": f"Validation error: {details}",
+            },
+        )
+
+    @app.exception_handler(Exception)
+    async def unhandled_error_handler(
+        _request: Request, exc: Exception
+    ) -> JSONResponse:
+        logger.error("Unhandled exception:\n%s", traceback.format_exc())
+        return JSONResponse(
+            status_code=500,
+            content={
+                "status": "error",
+                "data": None,
+                "error": "Internal server error",
+            },
+        )