Python flask and custom client error messages

Question

I'm currently writing a REST API for an app I'm working on. The app is written in python using flask. I have the following:

try:
    _profile = profile(
        name=request.json['name'],
        password=profile.get_salted_password('blablabla'),
        email=request.json['email'],
        created_by=1,
        last_updated_by=1
    )
except AssertionError:
    abort(400)

session = DatabaseEngine.getSession()
session.add(_profile)
try:
    session.commit()
except IntegrityError:
    abort(400)

The error handler looks like this:

@app.errorhandler(400)
def not_found(error):
    return make_response(standard_response(None, 400, 'Bad request'), 400)

I'm using the error 400 to denote both a problem with a sqlalchemy model validator and a unique constraint when writing to the database and in both cases the following error is sent to the client:

{
  "data": null,
  "error": {
    "msg": "Bad request",
    "no": 400
  },
  "success": false
}

Is there a way to still use abort(400) but also set the error somehow so that the error handler can take care of adding additional information for the error object in the result?

I would like it to be more in line with:

{
  "data": null,
  "error": {
    "msg": "(IntegrityError) duplicate key value violates unique constraint profile_email_key",
    "no": 400
  },
  "success": false
}

Answer 1

you can directly put a custom response in abort() function:

abort(make_response("Integrity Error", 400))

Alternatively, you can put it in the error handler function

@app.errorhandler(400)
def not_found(error):
resp = make_response("Integrity Error", 400)
return resp