Twitter API with jQuery

After spending some time with Twitter REST API and jQuery; I decided to develop a small application to test both of these together. The example uses jQuery Ajax commands to load the given users public timeline through Twitter REST API.

jQuery is awesome and very popular JavaScript library which provides zillions of operations to manipulate client side objects. jQuery Ajax operations make it very easy to call the Twitter REST API and get the data in JSON format. The following line of code will call the Twitter for a user public timeline.

var url = "http://twitter.com/status/user_timeline/"+ $("input#tweepal").val()+".json?callback=?"; 
$.getJSON( url, function( data ){
   // process the reply  
});

For simplicity I have taken a textbox to enter the Twitter username with id "tweepal". The Twitter REST url contains a query string parameter "callback" without which Twitter reply will not be available to the Ajax function. Once received the data can be accessed like a normal JavaScript object. The received object is an array of tweets which can be easily traversed with jQuery.each() function.

$.each(data, function(n, tweet){
      $("div#tweet_time").val(tweet.created_at);
      $("div#tweet_text").val(tweet.text);
});

This completes all the blocks required to interact with Twitter from client side only. 

However there are plenty of libraries available for Twitter but its always exiting to make something on your own (specially using Twitter). Well I am struggling on how to post update using OAuth in same example. Will definitely post if get success.

GWT client with REST

This article explains a small prototype i developed for a friend to show how REST services can be used can be used from the client code and avoid additional RPC call. The demo explains only two fundamental class structures to access the remote service.

RequestBuilder
GWT client API is having an HTTP request builder class which helps the application to make remote connection through HTTP request and supported methods (GET, POST).

RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, urlAddress);
builder.sendRequest("", new RequestCallback() {
  
  public void onResponseReceived(Request request, Response response) {
     //use response.getText() to get the resulting text from the service
  }


  public void onError(Request request, Throwable exception) {
     // exception handling
  }
});

XmlParser
GWT client API also provides XML parsing capabilities but to use that XML.gwt.xml has to be included in the modules file.

The following code can parse the XML text and prepare complex node list which can be traversed to access the attributes and node values.

    Document doc = XMLParser.parse(response.getText());

Once Document instance is generated program can start traversal from the root node or can search for the particular nodes based on the name.

    NodeList nodeList = doc.getChildNodes(); // to start from root node
    NodeList nodeList = doc.getElementsByTagName(nodeName);  // to start from selected node

Full source code with example services is available here.