dbc-node-serviceprovider

Abstraction layer for the DBC webservices. Handles the communication between the application- and the service layer providing optional transforms for transforming the data received from the services before returning it to the client.

Transforms

A transform is a form of event that takes a request and calls one or more services. When service calls are resolved the Transform transforms the response into the desired format. A transform is created with provider.registerTransform

ServiceClients

A ServiceClient is an implementation of a client that handles communication with a service

API 1.0

Provider

The provider needs to be initialized with a config file before usage.

  const Provider = require('dbc-node-serviceprovider');
  const provider = Provider(config);

Provider.registerServiceClient(client):ServiceClient

Method for registering serviceclients. Serviceclients need a name that refers to a config namespace, and an init() that provides the configurations and should return the client methods.

  import Recommendations from 'dbc-node-recommendations';
  
  provider.registerServiceClient({
    name: 'recommend',
    init(config) {
      return Recommendations(config.endpoint);
    }
  });

Provider#registerTransform(client):Transform

Method for registering transform classes. Transforms need events, requestTransform, responseTransform

  provider.registerTransform({
    event() {
      return 'transformEvent';
    },
    requestTranform(request) {
      // make a call to one or more services, using the callServiceClient method
      return this.callServiceClient('moreinfo::method', request);
    },
    requestResponse(response) {
      // do something with the reponse
      return response;
    }
  });

Transform#callServiceClient:Promise

On a transform it is possible to make calls to registered clients in the following format

  const promise = this.callServiceClient('client', 'method', params);

callServiceClient returns a promise that should be returned from the requestTransform

Provider#trigger(event, params):Promise

Triggers an event on the provider. If the event does not exists an error is thrown.
A transform with the corresponding event needs to be registered first.

the trigger method returns a Promise

  const recommendations = Provider.trigger('recommend', {like: ['123123123']});
  
  recommendations
    .then((result) => {
      console.log(result);
    })
    .catch((error) => {
      console.log(error)
    });  

Provider#bootstrap

activates the bundled transforms and clients

  provider.boostrap();

Provider#setupSockets

Setup socket api

  const app = express();
  const server = require('http').Server(app);
  const socket = require('socket.io').listen(server);
  
  provider.setupSockets(socket);

Events

The provider inherits the Events API which is used to register events from the registered transforms

Events#addEvent

add an event object

  Events.add('type', 'eventName', Function||Object);

Events#getEvent

Retrieve a single event object

  const event = Events.get('type', 'eventName');

Events#getEventsOfType

Returns a map of events of a specified type

  const map = Events.getEventsOfType('type');
  map.forEach((value, eventName) => console.log.bind(console));
  

Bundled clients

• MoreInfo.client.js
• OpenSearch.client.js
• OpenSuggest.client.js
• PopSuggest.client.js
• Recommendations.client.js

Bundled transforms

• CoverImage.transform.js
• ResultList.transform.js
• Work.transform.js
• OpenSuggest.transform.js
• PopSuggest.transform.js
• Recommendations.transform.js

API 2.0

Provider

The provider needs to be initialized with a config file before usage.

  const Provider = require('dbc-node-serviceprovider');
  const provider = Provider(someLoggerNotRequired);

Provider.registerServiceClient(name, client):ServiceClient

Method for registering serviceclients. Serviceclients need a name that refers to a config namespace, and an initialized client

  import Recommendations from 'dbc-node-recommendations';
  
  const recommendations = Recommendations(config);
  
  provider.registerServiceClient('recommend', recommendations);

Provider#registerTransform(object):Transform

Method for registering transform classes. Transforms need events, requestTransform, responseTransform

  provider.registerTransform({
    event() {
      return 'transformEvent';
    },
    requestTranform(request) {
      // make a call to one or more services, using the callServiceClient method
      return this.clients.recommend.getRecommendations(request);
    },
    requestResponse(response) {
      // do something with the reponse
      return response;
    }
  });

Transform#callServiceClient:Promise (DEPRICATED)

Call serviceClients through the clients object on the transform

  const promise = this.clients.nameSpace.method(params);

Client calls always returns a promise that should be returned from the requestTransform

Provider#trigger(event, params):Promise

Triggers an event on the provider. If the event does not exists an error is thrown.
A transform with the corresponding event needs to be registered first.

the trigger method returns a Promise

  const recommendations = Provider.trigger('recommend', {like: ['123123123']});
  
  recommendations
    .then((result) => {
      console.log(result);
    })
    .catch((error) => {
      console.log(error)
    });  

Provider#dispatcher

Setup socket api

  const app = express();
  const server = require('http').Server(app);
  const socket = require('socket.io').listen(server);
  
  provider.dispatcher(socket);

API 3.0

The new 3.0 api is almost identical to the 2.0 api, except it requires a socketcluster worker or something with an identical api.

Provider.dispatcher

  module.exports.run = function (worker) {
    const app = express();
    const server = worker.httpServer;
    const scServer = worker.getSCServer();
    
    server.on('request', app);
    
    ...
    
    provider.dispatcher(worker);
  }