json schema date-time does not check correctly

Question

I have a JSON and a JSON-schema

JSON:

{ "aaa": "4000-02-01 00:00:00" } 

JSON-schema:

{     "$schema": "http://json-schema.org/draft-04/schema",     "type": "object",     "properties": {          "aaa": {             "type": "string",             "format": "date-time"         }       }, "required": ["aaa"] } 

The JSON gets validated by the JSON-schema. However if I change the field aaa to "bla" the schema does not notice that it is not a date-time any longer.

Did I miss anything in the schema?

Answer 1

Validation with "format" is optional. This is partly because schema authors are allowed to completely make up new formats, so expecting all formats to be validated is not reasonable.

Your library should (if it is decent) have a way to register custom validators for particular formats. For example, the tv4 validation library (in JavaScript) has the tv4.addFormat() method:

tv4.addFormat('date-time', function (data) {     return isValidDate(data); }); 

Once you've done this, then "format": "date-time" in the schema should validate dates correctly.

Answer 2

For Python's jsonschema library, specify the format checker when calling validate:

jsonschema.validate(data, schema, format_checker=jsonschema.FormatChecker()) 

To validate a date-time format, the strict-rfc3339 package should be installed.

See Validating Formats.