asyncapi-validator

Validate messages through AsyncApi

Note: This package only support AsyncApi Schema v2.0.0 and above.

npm i asyncapi-validator

Features

• Validate your messages against your AsyncApi Document
• Validate your AsyncApi Document against AsyncApi Schema definition
• Load your AsyncApi Schema from local file or any URL
• Supports AsyncApi in JSON and YAML format
• Supports AsyncApi v2.0.0 and above

Content

• Class Methods
  • AsyncApiValidator.fromSource()
    • Options
• Instance Methods / Properties
  • .validate()
  • .validateByMessageId() - deprecated
  • .schema
• Example usage with .validate() method
• Example usage with .validateByMessageId() method
• Errors
  • Error Example

Class Methods

AsyncApiValidator.fromSource()

/** 
 * Load and Parse the schema from source.
 * @param {string | Object} source - local PATH or URL of schema or schema Object
 * @param {Object} options - options for validation
 * @returns {Promise}
 */
AsyncApiValidator.fromSource(source, options)

Options

value	type		description
msgIdentifier	string	required	Name of the parameter whose value will be used as "key" in .validate() method. Recommendation is to use "name" as described in message-object. You can also use Specification Extensions.
ignoreArray	boolean	optional	If true, then if schema is defined as an array and payload is an object, then payload will be placed inside an array before validation.
path	string	optional	Path to the AsyncApi document.

Instance Methods and Properties

.validate()

You should provide msgIdentifier in AsyncApiValidator options.

/**
 * Method to validate the Payload against schema definition.
 * @param {string} key - required - message key (as per msgIdentifier)
 * @param {Object} payload - required - payload of the message
 * @param {string} channel - required - name of the channel/topic
 * @param {string} operation - required - publish | subscribe | send | receive
 * @returns {boolean}
 */
.validate(key, payload, channel, operation)

.validateByMessageId() - deprecated

This method is deprecated as messageId was removed in AsyncApi v3.0.0. More details here asyncapi/spec/issues/978 .

Here messageId should be as defined in AsyncApi Schema v2.4.0. To use this method, your AsyncApi Schema version should be >= v2.4.0 and <3.0.0.

/**
 * Method to validate the Payload against schema definition.
 * @param {string} key - required - messageId
 * @param {Object} payload - required - payload of the message
 * @returns {boolean}
 */
.validateByMessageId(key, payload)

.schema

.schema property can be used to access AsyncApi schema in JSON format and with all the refs resolved.

Example usage with .validate() method

Schema

asyncapi: 3.0.0
info:
  title: Streetlights Kafka API
  version: 1.0.0
channels:
  lightingMeasured:
    messages:
      lightMeasured:
        $ref: '#/components/messages/lightMeasured'
operations:
  sendLightMeasurement:
    action: send
    channel:
      $ref: '#/channels/lightingMeasured'
    messages:
      - $ref: '#/channels/lightingMeasured/messages/lightMeasured'
components:
  messages:
    lightMeasured:
      x-unique-id: lightMeasured
      payload:
        $ref: '#/components/schemas/lightMeasuredPayload'
  schemas:
    lightMeasuredPayload:
      type: object
      properties:
        lumens:
          type: integer
          minimum: 0
          description: Light intensity measured in lumens.

const AsyncApiValidator = require('asyncapi-validator')
let va = await AsyncApiValidator.fromSource('./api.yaml', {msgIdentifier: 'x-unique-id'})

// validate 'lightMeasured' on channel 'lightingMeasured' with operation 'send'
va.validate('lightMeasured', {
  lumens: 0,
  sentAt: '2019-08-24T14:15:22Z'
}, 'lightingMeasured', 'send')

In above example, "msgIdentifier" is "'x-unique-id". That is why, "lightMeasured" is used as "key" in "va.validate()" method.

Example usage with .validateByMessageId() method

Schema

asyncapi: 2.4.0

info:
  title: User Events
  version: 1.0.0

channels:
  user-events:
    description: user related events
    publish:
      message:
        messageId: UserRemoved
        payload:
          type: object
          properties:
            userEmail:
              type: string
            userId:
              type: string

const AsyncApiValidator = require('asyncapi-validator')
let va = await AsyncApiValidator.fromSource('./api.yaml')

// validate messageId 'UserRemoved'
va.validateByMessageId('UserRemoved', {
  userId: '123456789',
  userEmail: 'alex@mail.com',
})

Errors

Error thrown from asyncapi-validator will have these properties.

key	type	value	description
name	string	AsyncAPIValidationError	AsyncAPIValidationError
key	string		"key" of payload against which schema is validated
message	string		errorsText from AJV
errors	array		Array of errors from AJV

Error Example

{
  AsyncAPIValidationError: data.type must be equal to one of the allowed values at MessageValidator.validate (.....
  name: 'AsyncAPIValidationError',
  key: 'hello',
  errors:
    [
      { keyword: 'enum',
        dataPath: '.type',
        schemaPath: '#/properties/type/enum',
        params: [Object],
        message: 'must be equal to one of the allowed values'
      }
    ]
}