Cache PHP Output - php

Question

I have a file called api.php which is loaded using parameters, for example:
api.php?name=NAME&format=xml
which would return a xml page with some data, or
api.php?name=NAME&format=JSON would return the same data in json format.
The xml page is generated using this:
function generate_valid_xml_from_array($array, $node_block='xboxapi', $node_name='game') {
$xml = '<?xml version="1.0" encoding="UTF-8" ?>' . "\n";
$xml .= '<' . $node_block . '>' . "\n";
$xml .= generate_xml_from_array($array, $node_name);
$xml .= '</' . $node_block . '>' . "\n";
return $xml;
}
$xml = generate_valid_xml_from_array($array);
header('Content-type: text/xml');
print $xml;
and the json is returned using this:
header('Content-type: application/json');
echo json_encode($data);
How would i set the returned data to be cached for 1 hour, and then updated hourly on request?
I have been scratching my head with this one for a while now

Answer 1

You can use a filesystem cache for your needs. Here is a link to an article describing the creation of a simple cache class:
http://devgrow.com/simple-cache-class/
Another possibility would be to use the Zend Cache classes from the Zend Framework, for more information look at the introduction chapter of the component in the Zend Framework manual:
http://framework.zend.com/manual/en/zend.cache.introduction.html
And if you Google for 'PHP cache class' you will get a lot of other possibilities you can check.

Answer 2

You could store it in a file or in your database together with information about the creation time. If someone queries it you check if the creation time is more than 60 minutes in the past. If not return your cached value, if it is too old rebuild your value, save it and return it afterwards.