asyncapi-validator

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

Class Methods

AsyncApiValidator.fromSource()

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

Instance Methods

.validate()

/**
 * 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

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: '[e-mail]',
}, '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 should 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: 'should be equal to one of the allowed values'
      }
    ]
}

How it works

asyncapi-validator validates the payload of the messages of a certain message, as described in your schema document. To validate against a certain message, it needs to find the message are you pointing to in schema document. For that, you need to pass it key, channel, and operation of the message.

validate(key, payload, channel, operation)

• One channel should be defined only once in your whole schema document.
• The key should be unique for an operation on a channel.

That means,

• Messages going to different operations on one channel, can have same key.
• Messages going to different channels, can have same key