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<h1> Retrieving a Y! Weather RSS Feed</h1>
<p>
This example demonstrates how to use the Connection Manager and a PHP proxy -- to work around XMLHttpRequest's same-domain policy &mdash; to retrieve an XML document from http://xml.weather.yahoo.com/forecastrss.
</p>

<h3>Source file and dependencies</h3>
<p>Load the YAHOO namespace and connection manager source file</p>
<textarea name="code" class="JScript" cols="60" rows="1">
  &lt;script src="yahoo.js"&gt;
  &lt;script src="connection.js"&gt;
</textarea>

<h3>Callback Object and the Weather RSS</h3>
<p>Yahoo! Weather RSS will return an XML document if the transaction is successful. The following callback object with success and failure handlers is used to process the response.</p>
<textarea name="code" class="JScript" cols="60" rows="1">
// This is the response display container
var div = document.getElementById('weatherModule');
// This is a reference to the HTML form.
var oForm = document.getElementById('wForm');

/*
 * This method will traverse the response XML document and build a
 * simple HTML module comprised of data from the following tags:
 *
 * Data in the first <title> tag in the document.
 * Data in the first <lastBuildDate> tag in the document.
 * HTML from the second <description> tag in the document.
 *
 */
function successHandler(o){
	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;

	// Format and display results in the response container.
	div.innerHTML = "<p>" + oTitle + "</p>" + "<p>" + oDateTime + "</p>" + descriptionNode;
}

/*
 *
 * This is a simple failure handler that will display
 * the HTTP status code and status message if the resource
 * returns a non-2xx code.
 *
 */
function failureHandler(o){
	div.innerHTML = o.status + " " + o.statusText;
}
</textarea>

<h3>Assemble the Querystring and Initiate the Transaction</h3>
<p>The Yahoo! Weather RSS feed requires a simple HTTP GET request, with a base URL and a parameters querystring.  In this example, we will use the following parameters:</p>
<ul>
	<li>p - location as U.S. Zip Code or Location ID</li>
	<li>u - temperature units</li>
</ul>

<p>The following are some example location IDs (do not include the city name):</p>
<ul>
	<li>Beijing: <em>CHXX0008</em></li>
	<li>Helsinki: <em>FIXX0002</em></li>
	<li>London: <em>UKXX0085</em></li>
	<li>Moscow: <em>RSXX0063</em></li>
	<li>Munich: <em>GMXX0087</em></li>
	<li>Paris: <em>FRXX0076</em></li>
	<li>Riyadh: <em>SAXX0017</em></li>
	<li>Tokyo: <em>JAXX0085</em></li>
</ul>
<p>For more details on the Y! Weather RSS feed and other location IDs, please visit <a href="http://developer.yahoo.com/weather/index.html">http://developer.yahoo.com/weather/index.html</a>.
<p>Function getModule retrieves the input values for location and temperature and creates a querystring.</p>
<textarea name="code" class="JScript" cols="60" rows="1">
function getModule(){

	// retrieve the field values for the zip code
	// input and the unit input.
	var sLocation = oForm.elements['zip'].value;
	var sUnit = oForm.elements['unit'].value;

	// entryPoint is the base URL
	var entryPoint = 'php/weather.php';

	// queryString is the key-value pairs of zip and unit.
	var queryString = encodeURI('?p=' + sLocation + '&' + 'u=' + sUnit);
	var sUrl = entryPoint + queryString;

	// Initiate the HTTP GET request.
	var request = YAHOO.util.Connect.asyncRequest('GET', sUrl, { success:successHandler, failure:failureHandler });
}
</textarea>

<h3>Proxy and Response</h3>
<p>
Once weather.php receives the querystring, it will construct and send an HTTP GET using CURL to retrieve the results from the Yahoo! Weather RSS feed.  This allows the transaction to succeed while working around XMLHttpRequest's security policy.
</p>
<textarea name="code" class="JScript" cols="60" rows="1">
<?php

// Since the result is an XML document, the Content-type
// header must be set to "text/xml" for the data to be
// treated as XML and to populate responseXML.
header("Content-Type:text/xml");

// $url is the resource path of the Y! Weather RSS
// with the appended querystring of zip code/location id and
// temperature unit.
$url = 'http://xml.weather.yahoo.com/forecastrss?'.getenv('QUERY_STRING');

// This function initializes CURL, sets the necessary CURL
// options, executes the request and returns the results.
function getResource($url){
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $result = curl_exec($ch);
        curl_close($ch);

        return $result;
}

// Call getResource to make the request.
$feed = getResource($url);

// Return the results.
echo $feed;
?>
</textarea>

<form id="wForm">
<fieldset>
	<label>Zip Code or Location ID</label> <input type="text" name="zip" value="94089">
	<p>Please enter a U.S. Zip Code or a location ID to get the current temperature.  The default is Zip Code 94089 for Sunnyvale, California; its location ID is: USCA1116.</p>
</fieldset>
<fieldset>
<label>Unit</label> <input type="text" name="unit" length="1" maxlength="1">
<p>Enter *F* for Fahrenheit or *C* for Celsius temperature unit.
</fieldset>
<div id="weatherModule"></div>
<input type="button" value="Get Weather RSS" onClick="getModule()">
</form>
<script>
var div = document.getElementById('weatherModule');
var oForm = document.getElementById('wForm');

function successHandler(o){
	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.innerHTML = "<p>" + oTitle + "</p>" + "<p>" + oDateTime + "</p>" + descriptionNode;
}

function failureHandler(o){
	div.innerHTML = o.status + " " + o.statusText;
}

function getModule(){
	var iZip = oForm.elements['zip'].value;
	var sUnit = oForm.elements['unit'].value;
	var entryPoint = 'php/weather.php';
	var queryString = encodeURI('?p=' + iZip + '&' + 'u=' + sUnit);
	var sUrl = entryPoint + queryString;
	var request = YAHOO.util.Connect.asyncRequest('GET', sUrl, { success:successHandler, failure:failureHandler });
}

</script>
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