Class: ServiceRegistrationInfo

ServiceRegistrationInfo(client, serviceType)

Service registration instances are used to register and expose services onto a DXL fabric.

DXL Services are exposed to the DXL fabric and are invoked in a fashion similar to RESTful web services. Communication between an invoking client and the DXL service is one-to-one (request/response).

Each service is identified by the "topics" it responds to. Each of these "topics" can be thought of as a method that is being "invoked" on the service by the remote client.

Multiple service "instances" can be registered with the DXL fabric that respond to the same "topics". When this occurs (unless explicitly overridden by the client) the fabric will select the particular instance to route the request to (by default round-robin). Multiple service instances can be used to increase scalability and fault-tolerance.

The following demonstrates registering a service that responds to a single topic with the DXL fabric. After registering the service, the example invokes the request via the use of the Client#asyncRequest method.

Constructor

new ServiceRegistrationInfo(client, serviceType)

Parameters:
Name Type Description
client Client

The Client instance that will expose this service.
serviceType String

A textual name for the service. For example, "/mycompany/myservice".
Source:
Example
// Create service registration object
var info = new dxl.ServiceRegistrationInfo(client, 'myService')
// Add a topic for the service to respond to
info.addTopic(SERVICE_TOPIC,
  // Handle the receipt of an incoming service request
  function (request) {
    // Extract information from request
    console.log('Service received request payload: ' + request.payload)
    // Create the response message
    var response = new dxl.Response(request)
    // Populate the response payload
    response.payload = 'pong'
    // Send the response
    client.sendResponse(response)
  })
// Register the service with the fabric
client.registerServiceAsync(info,
  function (error) {
    // If an error did not occur, invoke the service (send a request)
    if (!error) {
      // Create the request message
      var request = new dxl.Request(SERVICE_TOPIC)
      // Populate the request payload
      request.payload = 'ping'
      // Send the request
      client.asyncRequest(request,
        // Handle the response to the request
        function (error, response) {
          // Destroy the client - frees up resources so that the
          // application stops running
          client.destroy()
          // Extract information from the response (if an error did not
          // occur)
          if (!error) {
            console.log('Client received response payload: ' +
              response.payload)
          }
        })
    }
  })

Members

destinationTenantGuids :Array.<String>

The set of tenant identifiers that the service will be available to. Setting this value will limit which tenants can invoke the service.

Type:
  • Array.<String>
Default Value:
  • []
Source:

metadata :Object

An object of name-value pairs that are sent as part of the service registration. Brokers provide a registry service that allows for registered services and their associated meta-information to be inspected. The metadata is typically used to include information such as the versions for products that are exposing DXL services, etc.

Type:
  • Object
Default Value:
  • {}
Source:

serviceId :String

A unique identifier for the service instance (automatically generated when the ServiceRegistrationInfo object is constructed).

Type:
  • String
Source:

serviceType :String

A textual name for the service. For example, "/mycompany/myservice".

Type:
  • String
Source:

topics

Properties:
Type Description
Array.<String>

An array containing the string name of each topic that the service responds to.
Source:

ttl :Number

The interval (in minutes) at which the client will automatically re-register the service with the DXL fabric.

Type:
  • Number
Default Value:
  • 60
Source:

Methods

addTopic(topic, callback)

Registers a topic for the service to respond to along with the request callback that will be invoked.

Parameters:
Name Type Description
topic String

The topic for the service to respond to.
callback function

The request callback that will be invoked when a Request message is received. The Request object is supplied as the only parameter to the request callback function.
Source:

addTopics(callbacksByTopic)

Registers a set of topics for the service to respond to along with their associated request callbacks.

Parameters:
Name Type Description
callbacksByTopic Object

Object containing a set of topics for the service to respond to along with their associated request callback instances. Each key in the object should have a string representation of the topic name. Each corresponding value in the object should contain the function to be invoked when a Request message is received. The Request object is supplied as the only parameter to the request callback function.
Source:

callbacks(topic) → {Array.<function()>}

Returns an array of functions which should be called upon receipt of a Request with the supplied topic.

Parameters:
Name Type Description
topic String

Topic for which to return associated callback functions.
Source:
Returns:

Array of callback functions for the topic.

Type
Array.<function()>