Subscribing to Connection Manager Global Events

Source file and dependencies

Load the Yahoo Global Object and Connection Manager source file:

<script src="yahoo.js"></script> <script src="event.js"></script> <script src="connection.js"></script>

Assemble the Querystring

Construct a simple querystring with a key-value pair of s = hello world. This data will be sent back to the client as a response from PHP to confirm the transaction.

/* * Create a querystring with example key-value pair of * hellow = world. Remember to encode the querystring * if and when the string contains special characters. */ var sUrl = "php/get.php?s=hello%20world";

Create an Event Handler Object

Create an object to handle the global custom events fired by Connection Manager.

var div = document.getElementById('container'); var globalEvents = { start:function(type, args){ div.innerHTML += "<li>Transaction " + args[0].tId + " " + type + " fired.<li>"; }, complete:function(type, args){ div.innerHTML += "<li>Transaction " + args[0].tId + " " + type + " fired.<li>"; }, success:function(type, args){ div.innerHTML += "<li>Transaction " + args[0].tId + " " + type + " fired.<li>"; if(args[0].responseText !== undefined){ div.innerHTML += "<li>Transaction id: " + args[0].tId + "<li>"; div.innerHTML += "<li>HTTP status: " + args[0].status + "<li>"; div.innerHTML += "<li>Status code message: " + args[0].statusText + "<li>"; div.innerHTML += "<li>HTTP headers: " + args[0].getAllResponseHeaders + "<li>"; div.innerHTML += "<li>Server response: " + args[0].responseText + "<li>"; div.innerHTML += "<li>Argument object: Array ( [foo] => " + args[0].argument[0] +" [bar] => " + args[0].argument[1] +" )<li>"; } }, failure:function(type, args){ div.innerHTML += "<li>Transaction " + args[0].tId + " " + type + " fired.<li>"; if(args[0].responseText !== undefined){ div.innerHTML += "<li>Transaction id: " + args[0].tId + "<li>"; div.innerHTML += "<li>HTTP status: " + args[0].status + "<li>"; div.innerHTML += "<li>Status code message: " + args[0].statusText + "<li>"; } }, abort:function(type, args){ div.innerHTML += "<li>Transaction " + args[0].tId + " " + type + " fired.<li>"; } };

Let's create two functions to provide handlers for callback.success and callback.failure compatibility. The inclusion of these handlers will demonstrate the callback object's compatibility with Custom Events.

var handleSuccess = function(o){ div.innerHTML += "<li>Success response handler triggered in callback.success<li>"; }; var handleFailure = function(o){ div.innerHTML += "<li>Failure response handler triggered in callback.success<li>"; };

Subscribe to the global custom events fired by Connection Manager before starting the transaction.

/* Subscribe to global listeners */ // Create a shorthand variable for YAHOO.util.Connect var YCM = YAHOO.util.Connect; YCM.startEvent.subscribe(globalEvents.start); YCM.completeEvent.subscribe(globalEvents.complete); YCM.successEvent.subscribe(globalEvents.success); YCM.failureEvent.subscribe(globalEvents.failure); YCM.abortEvent.subscribe(globalEvents.abort);

Initiate the Transaction

Call YAHOO.util.Connect.asyncRequest to make a request to get.php, and PHP will return the contents of $_GET via print_r(). Each event handler in globalEvents will be triggered in response to its corresponding custom event(e.g., globalEvents.start will be called when startEvent fires). In this example, event handlers are created and subscribed to all possible events raised by Connection Manager.

var request = YAHOO.util.Connect.asyncRequest('GET', sUrl);