This example demonstrates how to use IO to make a cross-domain request to `http://weather.yahooapis.com/forecastrss`. To try out the example, fill in your five-digit US zip code, or Location ID.
Notes:
- For Security reasons, YUI has removed all Flash files from the repository. As a result, this example will not function as it relies on Flash for the cross-domain transport. The code for this example will work if you compile and host the
io.swf file. Necessary source files for compilation are available in the yui3-swfs repository.
- This example will not function on iOS devices due to the usage of Flash as the cross-domain transport. This example may not work on older Android devices, as well.
{{>io-weather-source}}
Exploring the Code for This Example
Create a YUI instance, using IO, for this example:
```
//Create a YUI instance including support for cross-domain IO:
YUI().use("io-xdr", "node", function(Y) {
// Y is the YUI instance.
// The rest of the following code is encapsulated in this
// anonymous function.
} );
//Configure the cross-domain transport:
var xdrConfig = {
id:'flash', //We'll reference this id in the xdr configuration of our transaction.
src:'io.swf' //Relative path to the .swf file from the current page.
};
Y.io.transport(xdrConfig);
```
Callback Object and the Weather RSS
Yahoo! Weather RSS will return an XML document if the transaction is successful. The following success callback handlers is used to process the response.
```
//Define a function to handle a successful response from
//Yahoo! Weather. The success handler will find the response
//object in its second argument:
function successHandler(id, o){
Y.log("Success handler called; handler will parse the retrieved XML and insert into DOM.", "info", "example");
var root = o.responseXML.documentElement;
var oTitle = root.getElementsByTagName('description')[0].firstChild.nodeValue;
var oDateTime = root.getElementsByTagName('lastBuildDate')[0].firstChild.nodeValue;
var descriptionNode = root.getElementsByTagName('description')[1].firstChild.nodeValue;
div.set("innerHTML", "" + oTitle + "
" + "" + oDateTime + "
" + descriptionNode);
Y.log("Success handler is complete.", "info", "example");
}
```
Assemble the Querystring and Initiate the Transaction
The Yahoo! Weather RSS feed requires a simple HTTP GET request with a base URL and a querystring containing the required information as a name-value pair. In this example, we will use the following parameter:
- p — location as U.S. Zip Code or Location ID
The following are some example Location IDs (do not include the city name):
- Beijing: CHXX0008
- Helsinki: FIXX0002
- London: UKXX0085
- Moscow: RSXX0063
- Munich: GMXX0087
- Paris: FRXX0076
- Riyadh: SAXX0017
- Tokyo: JAXX0085
For more details on the Yahoo! Weather RSS feed and other location IDs, please visit http://developer.yahoo.com/weather/index.html.
Function getModule retrieves the input values for location and creates a querystring:
```
//When the Get RSS button is clicked, this function will fire
//and compose/dispatch the IO request:
function getModule(){
//Get the input value:
var iZip = Y.one('#zip').get("value");
//Create a querystring from the input value:
var queryString = encodeURI('?p=' + iZip);
//The Yahoo! Weather feed.
var entryPoint = 'http://weather.yahooapis.com/forecastrss';
//Compile the full URI for the request:
var sUrl = entryPoint + queryString;
Y.log("Submitting request; zip code: " + iZip, "info", "example");
//Make the reqeust:
var request = Y.io(sUrl, {
method:"GET",
on:
{
success:successHandler,
failure:failureHandler
}
}
);
}
//Add the click handler to the Get Weather RSS button as soon
//as the Flash transport has loaded, indicated by the firing
//of event "io:xdrReady".
Y.on('io:xdrReady', function() {
var btn = Y.one("#getWeather");
btn.set("disabled", false);
//Use the Event Utility to wire the Get RSS button
//to the getModule function.
Y.on("click", getModule, "#getWeather");
});
```
Full Script Source
Here is the full JavaScript source for this example:
```
{{>io-weather-source}}
```