Creating a custom type with a custom validation function

[Paul Winkler]

Hi folks,

I have been trying to figure out how to declare a custom type so that I can write a validation function.

I've been scratching my head over `extends` and getting nowhere.

The goal is to be able to first define a custom type definition in my schema, and then register a validation function that's triggered on that type:

    'properties': {

        "foo_daterange": {

            "$ref": "#/definitions/dateRange"

        },

    },

    "definitions": {

        "dateRange": {

            "properties": {

                "from": {

                    "type": "string",

                    "format": "date",

                },

                "to": {

                    "type": "string",

                    "format": "date",

                },

            },

            "required": ["to", "from"],

        },

    },

So far so good, this part seems to work OK.

But then I want to write, and register on an extended Validator, a validation function which asserts eg. that a dateRange instance has "from" less than "to".

So that this document would raise a validation error because "from" is greater than "to":

example = {

    "foo_daterange": {

        "from": "2014-11-23",

        "to": "2014-11-20",

    },

}

I have been staring at the 'extends' documentation and I'm stumped. Has anyone got an example of this sort of thing?  Here's what I've tried:

def date_range_validator(validator, value, instance, schema):

    import pdb; pdb.set_trace()

    start = value['from_date']

    end = value['to_date']

    import datetime

    start = datetime.datetime.strptime(start, '%Y%m%d')

    end = datetime.strptime(end, '%Y%m%d')

    assert start <= end

new_validators = {

    'dateRange': date_range_validator,

}

MyValidator = validators.extend(

    Draft4Validator,

    validators=new_validators)

# If I were doing it right, this would hit pdb ... but it doesn't.

MyValidator(example).validate() 

[Julian Berman]

Hey!

So you're defining a dateRange validator but you never use it :) which is why your function isn't called.

You have a $ref which is basically just a simple form of inlining, so you can just imagine the result which just inlines your definition, but all that it will have is a properties and a required validator inside.

Is your end goal to write some schemas that make use of a dateRange validator, or just to validate some from and to keys that you have in your schema?

Cheers,
Julian

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