Javascript Client

Javascript Client API

This is a brief explanation of the Javascript client API, Hermes.js, which closely resembles the C# API. Hermes.js differs from the C# library in one important way: All REST requests are performed asyncronously.

What you will need

From the JsClient project:

• Hermes.js
• RestClient.js
• jquery.json2xml.js
• jquery.jfeed.js (slightly modified to work with Hermes)

From MSDN

• Rx.js
• Rx.jQuery.js Due to EULA restrictions, these are not included.

From any official source:

• jQuery (tested with v1.6.2)
• Some knowledge of jQuery promises.

Subscribing to messages

var hermesUrl = 'http://server.domain.com/Hermes';
new HermesClient(url).TryCreateGroup('Chat Server', 'Website chat group')
                     .TryCreateTopic('Weather', 'Weather alerts')
                     .PollFeed(500)
                     .Subscribe(function (message) {
                        console.log('Weather alert: ' + message);
                     });

Publishing string messages

var hermesUrl = 'http://server.domain.com/Hermes';
var topicProxy = new HermesClient(hermesUrl)
                 .TryCreateGroup('Chat Server', 'Website chat group')
                 .TryCreateTopic('Weather', 'Weather alerts');
topicProxy.PostStringMessage('Hurricane Warning');

Publishing data messages

Here's an example of publishing a JSON message:

var hermesUrl = 'http://server.domain.com/Hermes';
var topicProxy = new HermesClient(hermesUrl)
                 .TryCreateGroup('ShoppingCart','')
                 .TryCreateTopic('Cart abcdef1234567890');
var message = {Type: 'ItemAddedEvent', ItemId: '123456', Quantity: 2};
var data = JSON.stringify(message);
topic.PostMessage(data, 'application/json');

Types

• Hermes Client: This is the entry point for the client API.
• Group: Represents a Hermes group on the server.
• Group Proxy: A promise for a Group, and provides most Group methods.
• Topic: Represents a Hermes topic on the server.
• Topic Proxy: A promise for a Topic, and provides most Topic methods.
• Observable: A standard Reactive Extensions for Javascript Observable. Refer to the Rx documentation for more information.
• Subscription: Used internally to manage a topic subscription.
• RestClient: Used internally to communicate with the Hermes REST service.