Posted by naixn on 12/02/06 19:24

Martien van Wanrooij wrote :
>
> "naixn" <naixn@won-fma.com> schreef in bericht
> news:4571ccff$0$24440$79c14f64@nan-newsreader-05.noos.net...
>> But there's another solution : you can, on the page that displays the
>> dates,
>> check the last modification time of the HTML cache file, and if it was
>> modified before one day ago, you update the cache ( by doing the SQL
>> request ),
>> and then display the cache file ( since it has been updated... :D ).
> Thanks this is a wonderful suggestion. My hosting provider gives me the
> right to give writing access to certain folders and I guess that in
> rough lines, caching means: writing data to a file on the server when a
> request is made from a client?
>> That would give you : one SQL request a day. Not so many, eh? :)
> Enough info to study the topic seriously, one more question. You say,
> with a smiley though, one SQL request a day so it could mean that the
> very first visitor tonight at 0:00 generates a SQL request and that
> request writes "something" to the caching file , when the second visitor
> shows up at 0:05, he get his data from that recently update file? Sorry
> to ask it in such a simplified way but with all due respect to all these
> wonderful cms'es I want to understand the topic as thoroughly as possible.
>
> Martien

Yep that's quite it. To simplify :
You get your site working.
Someone arrives on the page at 10 AM.
There is no file where datas where cached
-> Your system queries the database, and write the adequate HTML depending on
the result into a file, as it would usually output.
Your system include the cache file, meaning it outputs the db results.
Another ppl arrives on the page at 11.05 AM.
A cache file exists.
It's modification time is less than one day
No update needed
Include the cache file.
[...]
Some guy arrives on the page at 10.30 AM the day after.
A cache file exists.
But it was modified more than 24h ago.
-> Your system query the database...
Include cache file.
etc.

A cache file is no more than a text/html file in which you write the desired
HTML output.

--
Naixn
http://fma-fr.net

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