Bug: date-time format not working

[JohannesHepp]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

I am having problems validating a json with a date-time format. The validator returns true for the following input:
JsonSchema

{"title":"Test","properties":{"name":{"type":"string"},"dateOfBirth":{"type":"string","format":"date-time"}}}

Json

{"name":"Test User","dateOfBirth": "test"}

Running the following code returns true and does not add any issues to the list:

val jsonSchemaValidator = JsonSchema.fromDefinition(schema)
val json = Json.encodeToJsonElement(DummySerializer(), entry)
val result = jsonSchemaValidator.validate(json, schemaValidationErrors::add)

Expected Behavior

I would expect the validator to fail on this input because the dateOfBirth property is not in the correct format.

JSON schema

{"title":"Test","properties":{"name":{"type":"string"},"dateOfBirth":{"type":"string","format":"date-time"}}}

Library version

0.2.2

Anything else?

No response

[OptimumCode]

Hi, @JohannesHepp

First of all, many thanks for using the library!

TLTR: This is expected behaviour. To achieve what you want please use the following way of creating a schema

import io.github.optimumcode.json.schema.FormatBehavior.ANNOTATION_AND_ASSERTION
import io.github.optimumcode.json.schema.JsonSchemaLoader
import io.github.optimumcode.json.schema.SchemaOption

val jsonSchemaValidator = JsonSchemaLoader.create()
      .withSchemaOption(SchemaOption.FORMAT_BEHAVIOR_OPTION, ANNOTATION_AND_ASSERTION)
      .fromDefinition(schema)

If this does not solve the problem, please let me know

An explanation with details:

The behaviour you observe is the expected behaviour defined by the JSON schema specification.
This is the link to meta-schema for draft 2020-12 (you use it because you don't specify the $schema property explicitly and this draft is the latest one).
This is the part we are interested in:

{
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "$id": "https://json-schema.org/draft/2020-12/schema",
    "$vocabulary": {
        "https://json-schema.org/draft/2020-12/vocab/core": true,
        "https://json-schema.org/draft/2020-12/vocab/applicator": true,
        "https://json-schema.org/draft/2020-12/vocab/unevaluated": true,
        "https://json-schema.org/draft/2020-12/vocab/validation": true,
        "https://json-schema.org/draft/2020-12/vocab/meta-data": true,
        "https://json-schema.org/draft/2020-12/vocab/format-annotation": true,
        "https://json-schema.org/draft/2020-12/vocab/content": true
    },
   ...
}

The part that is related to your issue is https://json-schema.org/draft/2020-12/vocab/format-annotation": true,. It means that the format keyword only produces annotations.
To change this you can do one of the following things:

• enable format assertions in JsonSchemaLoader (in TLTR section)
• create a custom meta-schema that will have https://json-schema.org/draft/2020-12/vocab/format-assertion vocabulary enabled instead and specify this schema in the $schema property in your schema (this new meta-schema must be registered in the JsonSchemaLoader)
• enable vocabulary in your schema by defining the $vocabulary block:

    {
      "$vocabulary": {
          "https://json-schema.org/draft/2020-12/vocab/core": true,
          "https://json-schema.org/draft/2020-12/vocab/applicator": true,
          "https://json-schema.org/draft/2020-12/vocab/unevaluated": true,
          "https://json-schema.org/draft/2020-12/vocab/validation": true,
          "https://json-schema.org/draft/2020-12/vocab/meta-data": true,
          "https://json-schema.org/draft/2020-12/vocab/format-assertion": true,
          "https://json-schema.org/draft/2020-12/vocab/content": true
      },
      "title":"Test",
      "properties":{
        "name": {"type":"string"},
        "dateOfBirth":{"type":"string","format":"date-time"}
      }
    }

[JohannesHepp]

Hey @OptimumCode thanks for your quick reply. Yes, that was exactly what I was looking for.
Did I miss that part somewhere in your documentation? JsonSchema is a really extensive definition. I missed it there.

Probably adding a reference to this information in the Format part of your README would be helpful.
Thanks for your help. Works now.

[OptimumCode]

Probably adding a reference to this information in the Format part of your README would be helpful.

I agree. I will add this information to the Format section in the Readme file