Merge pull request #215 from grillazz/12-add-json-field-example

add more exception handlers

Author: grillazz

app/api/nonsense.py

@@ -22,11 +22,12 @@ async def create_nonsense(
 
 
 @router.get("/", response_model=NonsenseResponse)
-async def find_nonsense(
+async def get_nonsense(
     name: str,
     db_session: AsyncSession = Depends(get_db),
 ):
-    return await Nonsense.find(db_session, name)
+    nonsense = await Nonsense.get_by_name(db_session, name)
+    return nonsense
 
 
 @router.delete("/")

app/api/stuff.py

@@ -52,13 +52,8 @@ async def create_stuff(
 
 
 @router.get("/{name}", response_model=StuffResponse)
-async def find_stuff(name: str, db_session: AsyncSession = Depends(get_db)):
-    result = await Stuff.find(db_session, name)
-    if not result:
-        raise HTTPException(
-            status_code=status.HTTP_404_NOT_FOUND,
-            detail=f"Stuff with name {name} not found.",
-        )
+async def get_stuff(name: str, db_session: AsyncSession = Depends(get_db)):
+    result = await Stuff.get_by_name(db_session, name)
     return result
 
 
@@ -89,7 +84,7 @@ async def find_stuff_pool(
         HTTPException: If the 'Stuff' object is not found or an SQLAlchemyError occurs.
     """
     try:
-        stmt = await Stuff.find(db_session, name, compile_sql=True)
+        stmt = await Stuff.get_by_name(db_session, name, compile_sql=True)
         result = await request.app.postgres_pool.fetchrow(str(stmt))
     except SQLAlchemyError as ex:
         raise HTTPException(
@@ -105,7 +100,7 @@ async def find_stuff_pool(
 
 @router.delete("/{name}")
 async def delete_stuff(name: str, db_session: AsyncSession = Depends(get_db)):
-    stuff = await Stuff.find(db_session, name)
+    stuff = await Stuff.get_by_name(db_session, name)
     return await Stuff.delete(stuff, db_session)
 
 
@@ -115,6 +110,6 @@ async def update_stuff(
     name: str,
     db_session: AsyncSession = Depends(get_db),
 ):
-    stuff = await Stuff.find(db_session, name)
+    stuff = await Stuff.get_by_name(db_session, name)
     await stuff.update(**payload.model_dump())
     return stuff

app/database.py

@@ -1,5 +1,6 @@
 from collections.abc import AsyncGenerator
 
+from fastapi.exceptions import ResponseValidationError
 from rotoger import AppStructLogger
 from sqlalchemy.exc import SQLAlchemyError
 from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
@@ -26,15 +27,14 @@
 # Dependency
 async def get_db() -> AsyncGenerator:
     async with AsyncSessionFactory() as session:
-        # logger.debug(f"ASYNC Pool: {engine.pool.status()}")
         try:
             yield session
             await session.commit()
+        except SQLAlchemyError:
+            # Re-raise SQLAlchemy errors to be handled by the global handler
+            raise
         except Exception as ex:
-            if isinstance(ex, SQLAlchemyError):
-                # Re-raise SQLAlchemyError directly without handling
-                raise
-            else:
-                # Handle other exceptions
-                await logger.aerror(f"NonSQLAlchemyError: {repr(ex)}")
-                raise  # Re-raise after logging
+            # Only log actual database-related issues, not response validation
+            if not isinstance(ex, ResponseValidationError):
+                await logger.aerror(f"Database-related error: {repr(ex)}")
+            raise  # Re-raise to be handled by appropriate handlers

app/exception_handlers.py

@@ -1,12 +1,14 @@
 import orjson
 from fastapi import FastAPI, Request
+from fastapi.exceptions import ResponseValidationError
 from fastapi.responses import JSONResponse
 from rotoger import AppStructLogger
 from sqlalchemy.exc import SQLAlchemyError
 
 logger = AppStructLogger().get_logger()
 
-#TODO: add reasoning for this in readme plus higligh using re-raise in db session
+
+# TODO: add reasoning for this in readme plus higligh using re-raise in db session
 async def sqlalchemy_exception_handler(
     request: Request, exc: SQLAlchemyError
 ) -> JSONResponse:
@@ -30,6 +32,51 @@ async def sqlalchemy_exception_handler(
     )
 
 
+async def response_validation_exception_handler(
+    request: Request, exc: ResponseValidationError
+) -> JSONResponse:
+    request_path = request.url.path
+    try:
+        raw_body = await request.body()
+        request_body = orjson.loads(raw_body) if raw_body else None
+    except orjson.JSONDecodeError:
+        request_body = None
+
+    errors = exc.errors()
+
+    # Check if this is a None/null response case
+    is_none_response = False
+    for error in errors:
+        # Check for null input pattern
+        if error.get("input") is None and "valid dictionary" in error.get("msg", ""):
+            is_none_response = True
+            break
+
+    await logger.aerror(
+        "Response validation error occurred",
+        validation_errors=errors,
+        request_url=request_path,
+        request_body=request_body,
+        is_none_response=is_none_response,
+    )
+
+    if is_none_response:
+        # Return 404 when response is None (resource not found)
+        return JSONResponse(
+            status_code=404,
+            content={"no_response": "The requested resource was not found"},
+        )
+    else:
+        # Return 422 when response exists but doesn't match expected format
+        return JSONResponse(
+            status_code=422,
+            content={"response_format_error": errors},
+        )
+
+
 def register_exception_handlers(app: FastAPI) -> None:
     """Register all exception handlers with the FastAPI app."""
     app.add_exception_handler(SQLAlchemyError, sqlalchemy_exception_handler)
+    app.add_exception_handler(
+        ResponseValidationError, response_validation_exception_handler
+    )

app/models/nonsense.py

@@ -1,6 +1,5 @@
 import uuid
 
-from fastapi import HTTPException, status
 from sqlalchemy import String, select
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -20,22 +19,8 @@ class Nonsense(Base):
     # TODO: apply relation to other tables
 
     @classmethod
-    async def find(cls, db_session: AsyncSession, name: str):
-        """
-
-        :param db_session:
-        :param name:
-        :return:
-        """
+    async def get_by_name(cls, db_session: AsyncSession, name: str):
         stmt = select(cls).where(cls.name == name)
         result = await db_session.execute(stmt)
         instance = result.scalars().first()
-        if instance is None:
-            raise HTTPException(
-                status_code=status.HTTP_404_NOT_FOUND,
-                detail={
-                    "Record not found": f"There is no record for requested name value : {name}"
-                },
-            )
-        else:
-            return instance
+        return instance

app/models/stuff.py

@@ -35,7 +35,7 @@ class Stuff(Base):
 
     @classmethod
     @compile_sql_or_scalar
-    async def find(cls, db_session: AsyncSession, name: str, compile_sql=False):
+    async def get_by_name(cls, db_session: AsyncSession, name: str, compile_sql=False):
         stmt = select(cls).options(joinedload(cls.nonsense)).where(cls.name == name)
         return stmt