Does PHP's http stream wrapper cache files? Details?
<p>I'm looking for information about if and how PHP's http stream wrapper attempts cache files. Can anyone point to information about this? </p>

<p>An answer to this question, <a href="http://stackoverflow.com/questions/511476/does-phps-fopen-function-implement-some-kind-of-cache">Does PHPs fopen function implement some kind of cache?</a>, suggests that the wrapper may attempt to honor cache headers, but I have not found anything in the documentation about this. </p>

<p>Specifically I'm wondering:</p>

<ul>
<li>Will PHP cache files accessed http:// urls.</li>
<li>If it does, how long will it keep them?</li>
<li>Is there a maximum size for the cache?</li>
<li>Is there a maximum size per file that it will cache?</li>
<li>Does the cache persist between requests?</li>
<li>Out of curiosity, does it cache in memory or on disk? Where?</li>
</ul>
