宁静的Web服务错误处理

Question

In my API , when creating a new user, I call a number of functions:

userInfo = request.get_json()           
email = userInfo.get('email')       
password = userInfo.get('password')
validate_email(email)       
validate_password(password)     

if (no_errors):
    add_user_to_database(user)
else:
    return exception(?)

My goal is that I want to collect any and all errors that arise from the result of any of the first 3 function calls. It is possible that one function may catch more than one error.

Eg:

def validate_email(email):
    if email is None:
        # store error
    else:
        if email_already_on_server(email)
           # store error
        if email_too_long(email)
           # store error

    # What should I be doing here..

After I have all my errors stored, I want to return an exception(?) displaying all the errors that were picked up.

I'm not sure what the best way to do this is..

1) Should I create a single object (a custom error class) to pass to all my functions to store any errors ?

2) If errors are found, what should I return to the user? Would it be a custom exception , with a HTTP status code also containing all the errors in a JSON format?

I'm having a tough time getting my head around the proper way to do this.

Answer 1

With flask I like to use the jsonify library, then I format the errors in this way:

from flask import jsonify

def jsonifys(status_code=200, **kwargs):
    response = jsonify(**kwargs)
    response.status_code = status_code
    return response

Then I will raise errors from my methods and in my responses I will return the result like this:

return jsonifys(500, error='unable to create process')

So any frontend can easly read the error code and the message can provide any info desired. The JSON format also is handy.