使用另一个 JSON 架构验证 JSON 架构

Question

I am trying to validate JSON Schema using another JSON Schema.

Example of JSON Schema to validate: https://jsonschema.net/home

Reference of Validation schema to validate above schema: https://github.com/ajv-validator/ajv/blob/master/lib/refs/json-schema-draft-07.json

I have a requirement where property can only be of primitive type ie string, number, integer, boolean . Since the root of JSON schema should have type as object and all the properties inside it will have type as primitive type, I am not sure how should I define type definition that validates the type at root level as object while type inside properties as primitive type.

Sample JSON:

{
    "$schema": "http://json-schema.org/draft-07/schema",
    "$id": "http://example.com/example.json",
    "type": "object",
    "title": "The root schema",
    "description": "The root schema comprises the entire JSON document.",
    "default": {},
    "examples": [
        {
            "name": "A green door"
        }
    ],
    "required": [
        "name"
    ],
    "properties": {
        "name": {
            "$id": "#/properties/name",
            "type": "string",
            "title": "The name schema",
            "description": "An explanation about the purpose of this instance.",
            "default": "",
            "examples": [
                "A green door"
            ]
        }
    },
    "additionalProperties": true
}

Validation JSON that validates the type :

  definitions: {
    simpleTypes: {
      enum: ['array', 'boolean', 'integer', 'null', 'number', 'object', 'string'],
    }
  },
  properties: {
  type: {
      anyOf: [
        { $ref: '#/definitions/simpleTypes' },
      ],
    },
  }

From the above simpleTypes -> enum if I remove object , my JSON becomes invalid.

Any way I can define enum for root type as different from type present inside properties ?

Answer 1

Start by making a copy of the draft-07 schema and give it a unique $id .

{
  "$schema": "http://json-schema.org/draft-07/schema",
  "$id": "https://example.com/my-custom-draft-07-schema",
  "definitions": {
    ...original-definitions...
  },
  ...original-schema...
}

Since you want different constraints for schemas in different places, you'll need to refactor the schema to a definition so it can be referenced and extended for different situations. Don't forget to change all the recursive references ( { "$ref": "#" } ) to point to the definition you created ( { "$ref": "#/definitions/schema" } ).

{
  "$schema": "http://json-schema.org/draft-07/schema",
  "$id": "https://example.com/my-custom-draft-07-schema",
  "alllOf": [{ "$ref": "#/definitions/schema" }],
  "definitions": {
    ...original-definitions-with-modified-$refs...
   "schema": {
      ...original-schema-with-modified-$refs...
    }
  }
}

Next you'll need to add another definition specific to property schemas and change the $refs for property schemas to use the definition that was created ( { "$ref": "#/definitions/property-schema" } ). Don't forget to change patternProperties and additionalProperties as well as properties . Other keywords, such as anyOf should continue to reference the generic schema ( { "$ref": "#/definitions/schema" } ).

{
  "$schema": "http://json-schema.org/draft-07/schema",
  "$id": "https://example.com/my-custom-draft-07-schema",
  "alllOf": [{ "$ref": "#/definitions/schema" }],
  "definitions": {
    ...original-definitions-with-modified-$refs...
    "schema": {
      ...original-schema-with-modified-$refs...
    },
    "property-schema": {
      "allOf": [{ "$ref": "#/definitions/schema" }]
    }
  }
}

At this point, the schema has just been refactored. None of the behavior has changed except that you now have a place to put your custom constraints so they will only apply where you want them to. It should be relatively straightforward to add your constraints from here.

{
  "$schema": "http://json-schema.org/draft-07/schema",
  "$id": "https://example.com/my-custom-draft-07-schema",
  "alllOf": [{ "$ref": "#/definitions/schema" }],
  ...add-root-schema-constraints-here...
  "definitions": {
    ...original-definitions-with-modified-$refs...
    "schema": {
      ...original-schema-with-modified-$refs...
      ...add-global-constraints-here...
    },
    "property-schema": {
      "allOf": [{ "$ref": "#/definitions/schema" }]
      ...add-property-schema-constraints-here...
    }
  }
}