how to implement a simple cache system ?

[Michel V]

I'm having some little success with my news/weblog script, and was thinking about giving it one advantage of flat-files driven script: already generated files.

I would go for a cache system that would check for the last time the weblog has been updated, and if that's more recently than the cached file, serve the page and rebuild the file. Of course searches and things that use the querystring would always be dynamically generated.

Now I have two questions:
1/ How to check if the querystring is empty ?
2/ How would you go about implementing such a system ?

[Skunk]

You can check if the query string is empty like this:

if (empty($QUERY_STRING))
{
// No query string
}

As for the actual caching, the obvious thing is just to generate the whole page and store the HTML in a flat file somewhere, then like you said you can check the "last modified" time of that file to see how up to date the cache is.

If your page is generated with lots of seperate echo() statements an easy way of grabbing the contents of the page into a variable rather than displaying it is to use output buffering - turn it on, run the code as normal then at the end grab the contents of the output buffer into your variable before saving it in a file. More info on that can be found here:

http://www.php.net/manual/en/ref.outcontrol.php

[Eric.Coleman]

Actually.. you could start the output buffer at the top, end it at the bottom, flush it, and there ya go

I would look around at http://zend.com as well

[aspen]

this may interest you:

http://www.0x00.org/php/phpCache/

I use it. Its very customizeable as far as caching goes, for instance I edited it to keys the caches on path_info in addition to the other things.