Dave Dash2012-01-17T21:54:19-08:00http://davedash.com/Dave Dashdd+atom1@davedash.comCaching REST with sfFunctionCache2007-04-07T00:00:00-07:00http://davedash.com/2007/04/07/caching-rest-with-sffunctioncache<p>[tags]geocoding, caching, REST, symfony, Cache_Lite, php, cache, sfFunctionCache[/tags]</p>
<p>For <a href="http://reviewsby.us/">reviewsby.us</a> we do a lot of geocoding. To facilitate we use <a href="http://developer.yahoo.com/maps/rest/V1/geocode.html">Yahoo! Geocoding API</a>. This helps us normalize data, obtain latitude and longitude, interpret location specific searches.</p>
<p>These <acronym title="REpresentational State Transfer">REST</acronym> queries happen a lot and will continue to happen, but this data that Yahoo! provides is fairly static. We're basically querying a database of sorts. So it makes sense that we should cache this data.</p>
<p>We'll demonstrate how to cache these queries using <a href="http://symfony-project.com/">symfony</a>'s <a href="http://www.symfony-project.com/book/trunk/18-Performance#Caching%20the%20Result%20of%20a%20Function%20Call"><code>sfFunctionCache</code></a> class.</p>
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<p>I wrote a wrapper (I'll release it as a plugin if requested) for the <a href="http://developer.yahoo.com/maps/rest/V1/geocode.html">Geocoding API</a>, the bulk of the work (the <acronym title="REpresentational State Transfer">REST</acronym> call) occurs in a function called <code>doQueryGIS</code>:</p>
<div><textarea name="code" class="php">
public static function doQueryGIS($location)
{
$url = sfConfig::get('app_yahoo_geocode');
$query = array();
$query['appid'] = sfConfig::get('app_yahoo_app_id');
$query['location'] = $location;
$query['output'] = 'php';
$url .= '?' . http_build_query($query,null,'&');
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
$response = curl_exe c($curl);
// note there should be no space between curl_exe and c($curl)
// wordpress is just dumb
if ($response != 'Array')
{
return unserialize($response);
}
else
{
throw new sfException('Yahoo! GeoCoder does not understand: "'. $location . "\"\n");
}
return false;
}
</textarea></div>
<p>The call to this function is always wrapped with <code>queryGIS</code>:</p>
<div><textarea name="code" class="php">
protected function queryGIS()
{
$function_cache_dir = sfConfig::get('sf_cache_dir').'/function';
$cache = new sfFunctionCache($function_cache_dir);
$this->rawData = $cache->call(array('YahooGeo','doQueryGIS'), $this->rawLocation);
return $this->rawData;
}
</textarea></div>
<p>This wrapper creates a <code>sfFunctionCache</code> objet and calls the function and caches it for subsequent queries.</p>
<p>What this means is once Yahoo! teaches <a href="http://reviewsby.us/">reviewsby.us</a> that India is located at (25.42°, 77.830002°) and that the precision is 'country' we remember it in the future.</p>
<p>These features will be incorporated into future versions of <a href="http://reviewsby.us/">reviewsby.us</a>.</p>