flask errorhandler wont catch errors if view function returns an invalid response-CodePudding

I want to catch all errors and return an error in json format for my api project.

This is my error handler:

@app.errorhandler(Exception)
def handle_exception(e):
    if not isinstance(e, HTTPException):
        print(e)
        return {
            "code": 500,
            "name": "Internal Server Error",
            "description": repr(e),
        }, 500
    else:
        response = e.get_response()
        response.data = json.dumps({
            "code": e.code,
            "name": e.name,
            "description": e.description,
        })
        response.content_type = "application/json"
        return response

My errorhandler is catching exceptions if it happens inside the view function:

@api.get("/")
def all(user):
    a.b
    return []

This successfully catchs the following exception and return a json response:

name 'a' is not defined

But it is not catching if view function is fine but the return value is not json-friendly:

@api.get("/")
def all(user):
    return 1

It raises the folloing error and returns an error in html format.

TypeError: The view function did not return a valid response. The return type must be a string, dict, list, tuple with headers or status, Response instance, or WSGI callable, but it was a int.

CodePudding user response：

From the docs:

In debug mode, a handler for “500 Internal Server Error” will not be used. Instead, the interactive debugger will be shown.

Turning off the debug mode makes the handler handle 500 Internal Server Error also.