waleedashraf/asyncapi-validator

Message validator for Kafka/RabbitMQ/Anything through AsyncAPI schema

asyncapi-validator

Message validator through AsyncAPI schema

_Note: This package only support AsyncAPI Schema v2.0.0 and above. Since v3.0.0, support for older versions of AsyncAPI Schema has been removed.

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
  • .validateByMessageId()
  • .validate()
  • .schema
• Example usage with .validateByMessageId() method
• Example usage with .validate() 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
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.
msgIdentifier	string	optional (required only if you use .validate() method)	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.
path	string	optional	Path to the AsyncAPI document. It will be used to resolve relative references. Defaults to current working dir. As used in asyncapi-parser

Instance Methods / Properties

.validateByMessageId()

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.

/**
 * 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)

.validate()

To use this method for validation, you should provide msgIdentifier in AsyncApiValidator options.

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

.schema

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

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: '[email protected]',
})

Example usage with .validate() method

Schema

asyncapi: 2.0.0

info:
  title: User Events
  version: 1.0.0

channels:
  user-events:
    description: user related events
    publish:
      message:
        name: UserDeletedMessage
        x-custom-key: UserDeleted
        payload:
          type: object
          properties:
            userEmail:
              type: string
            userId:
              type: string

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

// validate 'UserDeleted' on channel 'user-events' with operation 'publish'
va.validate('UserDeleted', {
  userId: '123456789',
  userEmail: '[email protected]',
}, 'user-events', 'publish')

In above example, "msgIdentifier" is "x-custom-key". That is why, "UserDeleted" is used as "key" in "va.validate()" method.

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'
      }
    ]
}