Unable to validate the 'required' properties in an array of a JSON

Question

I have a draft-7JSON schema in a file like this:

{
    "$schema": "http://json-schema.org/draft-07/schema",
    "type": "object",
    "required": [
        "tenantid",
        "owningObjectId",
        "owningObject",
        "cudAction",
        "message"
    ],
    "properties": {
        "tenantid": {
            "type": "string",
            "default": ""
        },
        "owningObjectId": {
            "type": "string",
            "default": ""
        },
        "owningObject": {
            "type": "string",
            "default": "",
            "pattern": "^TeamUser$"
        },
        "cudAction": {
            "type": "string",
            "default": "",
            "pattern": "^c$"
        },
        "messageDateTime": {
            "type": "string",
            "default": ""
        },
        "encrypted": {
            "type": "boolean",
            "default": false
        },
        "message": {
            "type": "array",
            "items": {
                "type": "object",
                "required": [
                    "name",
                    "teamcode",
                    "enabled"
                ],
                "properties": {
                    "name": {
                        "type": "string",
                        "default": ""
                    },
                    "teamcode": {
                        "type": "string",
                        "default": ""
                    },
                    "org": {
                        "type": "string",
                        "default": ""
                    },
                    "enabled": {
                        "type": "boolean",
                        "default": false,
                    },
                    "version": {
                        "type": "string",
                        "default": ""
                    },
                    "orgDisplay": {
                        "type": "string",
                        "default": ""
                    }
                }
            }
        }
    }
}

I am validating JSON/response with this schema below:

# pip install jsonschema
from jsonschema import Draft7validator
def validate_response(response, schema_file_path: str) -> bool:
    """
    Validate the input message based on the input schema provided.
    :reference http://json-schema.org/understanding-json-schema/
    :param response: response received as JSON
    :param schema_file_path: The schema file path
    :return validated: returns True if valid response else False
    """
    validated = True
    with open(schema_file_path, "r") as schema_reader:
        schema = json.loads(schema_reader.read())
    errors = Draft7Validator(schema).iter_errors(response)
    for error in errors:
        print(error.message)
        validated = False
    if validated:
        print(f"Valid response")
    return validated

However, for a JSON like below faulty_json_response where the message field value array is empty and none of the required properties exists under the message field, the validator does not throw any error. What may be the cause?

faulty_json_response = {
        "tenantid": "5e3bb57222b49800016b666f",
        "owningObjectId": "5e680018ceb7d600012e4375",
        "owningObject": "TeamUser",
        "cudAction": "c",
        "messageDateTime": "1584460716.01416",
        "encrypted": false,
        "message": [],
    }

Please let me know if more details needed. Thank you.

score 2 · Accepted Answer · edited Oct 07 '21 at 07:24

2

The items keyword applies the subschema value (which includes our required), to each item in the applicable array (message in your case).

Given you have no items IN the message array, the subschema isn't applied, and so you don't get any validation errors.

If you want to specifiy the array has a minimum number of items, you can do that with the minItems keyword...

The value of this keyword MUST be a non-negative integer.

An array instance is valid against "minItems" if its size is greater than, or equal to, the value of this keyword.

Omitting this keyword has the same behavior as a value of 0.

https://datatracker.ietf.org/doc/html/draft-handrews-json-schema-validation-01#section-6.4.4

You can see this in action in this live demo https://jsonschema.dev/s/yMM0c

edited Oct 07 '21 at 07:24

Community

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answered Jul 27 '20 at 09:29

Relequestual

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Excellent, Ben. Combining this `minItems` with the existing `required` field has enabled me to achieve the desired behaviour. Thanks a lot. :) – Soumendra Jul 27 '20 at 10:00
do you mind sharing how did you include minItems in your schema? – Vaibhav Jul 16 '21 at 06:00
It would need to have been added to the value schema of `message`, as a sibling of `type` and `items`. Let me know if that's not enough and I'll make a GitHub Gist. – Relequestual Jul 16 '21 at 08:05

Unable to validate the 'required' properties in an array of a JSON

1 Answers1