Hi,
I'm developing a cache system. Which works in pseude code, like this:
class Cache {
function Fetchdata($id1,$id2,$id3) {
$id = md5($id1 . $id2 . $id3); if ($this->DataIsExpired($id)) return false; else return unserialize(file_get_contents($id));
}
function storeData($data,$id1,$id2,$id3) {
$id = md5($id1 . $id2 . $id3); OpenTheFileAndWriteTheDataSerialized($data); }
}
$id1 $id2 and $id3 are when they are combined unique
* Is there a chance of collision when MD5 is used on the id's and the ids are long strings
Yes there is a chance, but it's small enough that for practical purposes you can ignore it.
* Is file_get_contents the fastest way to open the file?
AFAIK yes it is since it takes advantage of memory mapping (where possible).
* Is serialize the fastest way to serialize ;) ?
Not sure.
* Are there any other things I should consider? (I'm aware of file-locking issues, and have taken care of that)
regards, Evert
Hmmmm... well, file_get_contents() doesn't lock the file so I'm interested in how you're accomplishing this feat. Perhaps you're creating a temporary directory (atomic IIRC) for the filename and then flocking that? I dunno, I hate race conditions.
You might also want to consider the security of the data that goes into your cache'd $_APP data. Because any file that is created by PHP is going to be in pretty much the same boat as the default session files and on a shared server, well...
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