I’m starting to develop a web application in PHP that I hope will become incredibly popular and make me famous and rich. 🙂
If that time comes, my decision whether to parse the API’s data as XML with SimpleXML or to use json_decode could make a difference in the app’s scalability.
Does anyone know which of these approaches is more efficient for the server?
Update: I ran a rudimentary test to see which method was more performant. It appears that json_decode is slightly faster executing than simplexml_load_string. This isn’t terribly conclusive because it doesn’t test things like the scalability of concurrent processes. My conclusion is that I will go with SimpleXML for the time being because of its support for XPath expressions.
<?php $xml = file_get_contents('sample.xml'); $json = file_get_contents('sample.js'); $iters = 1000; // simplexml_load_string $start_xml = microtime(true); for ($i = 0; $i < $iters; ++$i) { $obj = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA); } $end_xml = microtime(true); // json_decode $start_json = microtime(true); for ($i = 0; $i < $iters; ++$i) { $obj = json_decode($json); } $end_json = microtime(true); ?> <pre>XML elapsed: <?=sprintf('%.4f', ($end_xml - $start_xml))?></pre> <pre>JSON elapsed: <?=sprintf('%.4f', ($end_json - $start_json))?></pre> Result:
XML elapsed: 9.9836 JSON elapsed: 8.3606
As the ‘lighter’ format, I’d expect JSON to be slightly less stressful on the server, but I doubt it will be the biggest performance issue you find yourself dealing with as your site grows in popularity. Use whichever format you’re more comfortable with.
Alternatively, if you know how you’ll be structuring your data, you could try making an XML-formatted version and a JSON-formatted version and just run it against your setup a few hundred thousand times to see if it makes a noticeable difference.