JSON Schema Validation - networknt json-schema-validator : How to use the custom meta-schema for validation

[kggit]

Iam creating a custom meta-schema json file by extending the existing json-schema version 202012. How can i make json-schema-validator to use this custom meta-schema instead of default schema dialect from 202012?

Problem details:

I have created a JSON file in my local called "my_custom_meta_schema.json" which has following content:

{

  "$schema": "https://json-schema.org/draft/2020-12/schema",

  "$id": "https://domain/meta-schema/myschema/v1/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
  },
  "$dynamicAnchor": "meta",

  "title": "Core and Validation specifications meta-schema",
  "allOf": [
    {"$ref": "meta/core"},
    {"$ref": "meta/applicator"},
    {"$ref": "meta/validation"},
    {"$ref": "meta/format-annotation"},
    {"$ref": "meta/content"}
  ],
  "type": ["object", "boolean"],
  "properties": {
    "minDate": {
      "type": "string",
      "pattern": "\\d\\d\\d\\d-\\d\\d-\\d\\d",
      "format": "date"
    }
  }

}

Now, I will be creating a schema which uses the above meta-schema , It will start with something like :

{
  "$schema": "https://domain/meta-schema/myschema/v1/schema",
  "$id": "https://domain/retail/product.schema",
   ...
}

I am using networknt's json-schema-validator

implementation ("com.networknt:json-schema-validator:1.4.0")

How can I make JsonSchemaFactory to use the custom meta schema instead of default one?
My current function uses default 202012 draft . but I want to use my custom meta schema (extended from 202012 version) for validation

My current function (It doesn't use custom meta schema currently ):

     fun validateData(jsonData: Map<String, Any>): List<String> {
               val  jsonSchemafactory : JsonSchemaFactory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V202012)
               val config = SchemaValidatorsConfig()
               val objectMapper: ObjectMapper = ObjectMapper()
               config.pathType = PathType.JSON_POINTER
               val jsonSchemaInputStream: InputStream = resourceLoader.getResource("classpath:my_schema.json").inputStream
       
               val jsonNode: JsonNode = objectMapper.valueToTree(jsonData)
               val jsonSchema = jsonSchemafactory.getSchema(jsonSchemaInputStream)
               val validationResults = jsonSchema.validate(jsonNode)
               if (validationResults.isEmpty()) {
                   println("Validation successful")
               } else {
                   println("Validation failed")
               validationResults.forEach {
                  println(it.message)
                }
              }
             return validationResults.asSequence().map { it.message }.toList()
       }

[justin-tay]

Is there a specific reason why you want to specify your custom meta schema using a json file? In the first place to do this you would need to define a custom vocabulary for which you would associate your custom keyword implementations but your custom meta schema doesn't have any custom vocabulary. You then need to map the meta schema $id ie. https://domain/meta-schema/myschema/v1/schema to the retrieval iri which I assume is maybe classpath:my_custom_meta_schema.json. You'll also need to customize the vocabulary factory on the V202012 meta schema so it knows how to get your vocabulary with the keywords.

If you want to specify it by code you just have to create the meta schema with the keyword.

JsonMetaSchema metaSchema = JsonMetaSchema
                .builder("https://domain/meta-schema/myschema/v1/schema", JsonMetaSchema.getV202012())
                .keyword(new MinDateKeyword()).build();

Then use this when you create your factory.

JsonSchemaFactory.getInstance(VersionFlag.V202012, builder -> builder.metaSchema(metaSchema));

If you have resources on the classpath you should generally not load the schema in that way. You should be mapping the $id to the retrieval iri, ie the classpath.

You would typically map using a prefix and then place the resource in the correct folder structure

JsonSchemaFactory.getInstance(VersionFlag.V202012, builder -> builder.metaSchema(metaSchema)
        .schemaMappers(schemaMappers -> schemaMappers.mapPrefix("https://domain", "classpath:")));

Or if you really want

JsonSchemaFactory.getInstance(VersionFlag.V202012,
        builder -> builder.metaSchema(metaSchema).schemaMappers(schemaMappers -> schemaMappers.mappings(
                Collections.singletonMap("https://domain/retail/product.schema", "classpath:my_schema.json"))));

You can then load using SchemaLocation

JsonMetaSchema metaSchema = JsonMetaSchema
        .builder("https://domain/meta-schema/myschema/v1/schema", JsonMetaSchema.getV202012())
        .keyword(new MinDateKeyword()).build();

JsonSchemaFactory factory = JsonSchemaFactory.getInstance(VersionFlag.V202012,
        builder -> builder.metaSchema(metaSchema).schemaMappers(schemaMappers -> schemaMappers.mappings(
                Collections.singletonMap("https://domain/retail/product.schema", "classpath:my_schema.json"))));

JsonSchema schema = factory.getSchema(SchemaLocation.of("https://domain/retail/product.schema"));