Green: convert 422 to 400 on input errors

dev.py

@@ -1,4 +1,6 @@
-from fastapi import FastAPI, Depends, Request, HTTPException
+from fastapi import FastAPI, Depends, Request, HTTPException, status
+from fastapi.exceptions import RequestValidationError
+from fastapi.responses import JSONResponse
 
 from sqlalchemy.orm import Session
 
@@ -10,6 +12,23 @@ import schemas
 
 app = FastAPI()
 
+convert_422_to_400 = True
+
+
+if convert_422_to_400:
+    # Taken from there.
+    # https://stackoverflow.com/questions/75958222/can-i-return-400-error-instead-of-422-error
+    # https://stackoverflow.com/questions/71681068/how-to-customise-error-response-for-a-specific-route-in-fastapi
+
+    @app.exception_handler(RequestValidationError)
+    async def validation_exception_handler(
+        request: Request, exc: RequestValidationError
+    ):
+        return JSONResponse(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            content={"detail": exc.errors()},
+        )
+
 
 # Dependency
 def get_db():