Miscellaneous
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<?
/**
class.cacher.php -- Class used to cache a variable in serialized form.
Written by Serge Stepanov (serge_AT_gfxcafe.com).
Feel free to email me with questions. If you find this useful, would be great to hear from you.
version 1.0 -
Changes:
- First release.
Notes:
- Get() method will only use
the first occurrence, after which
the loop will be broken.
Example:
include("class.cacher.php");
$cache = new Cacher;
// Get var if not 60 seconds old
$variable = $cache->Get("variable_with_id", 60);
if (!$variable) {
// Cache file expired or is inexistant
// Do something to get new data
$cache->Set("variable_with_id", $newdata);
$variable = $newdata;
}
echo $variable;
**/
class Cacher {
var $cacheDir = "/tmp/"; // Where things are cached to (must have trailing slash!)
var $defaultCacheLife = "3600"; // How long to cache something for in seconds, default 1hr
/**
Set($varId, $varValue) --
Creates a file named "cache.VARID.TIMESTAMP"
and fills it with the serialized value from $varValue.
If a cache file with the same varId exists, Delete()
will remove it.
**/
function Set($varId, $varValue) {
$this->Delete($varId); // Clean up old caches with same varId
$fileHandler = fopen($this->cacheDir . "cache." . $varId . "." . time(), "a"); // Create new file
fwrite($fileHandler, serialize($varValue)); // Write serialized data
fclose($fileHandler);
}
/**
Get($varID, $cacheLife) --
Retrives the value inside a cache file
specified by $varID if the expiration time
(specified by $cacheLife) is not over.
If expired, returns FALSE
**/
function Get($varId, $cacheLife="") {
$cacheLife = (!empty($cacheLife)) ? $cacheLife : $this->defaultCacheLife; // Set default cache life
/* Loop through the directory looking for cache file */
$dirHandler = dir($this->cacheDir);
while ($file = $dirHandler->read()) {
/* Check for cache file with requested varId */
if (preg_match("/cache.$varId.[0-9]/", $file)) {
$cacheFileName = explode(".", $file); // Cache filename array
$cacheFileLife = $cacheFileName[2]; // Cache file creation time
$cacheFile = $this->cacheDir . $file; // Full location
/* Check to see if cache file has expired or not */
if ((time() - $cacheFileLife) < $cacheLife) {
$fileHandler = fopen($cacheFile, "r");
$varValueResult = fread($fileHandler, filesize($cacheFile));
fclose($fileHandler);
return unserialize($varValueResult); // Still good, return unseralized data
} else {
break; // Cache expired, break loop
}
}
}
$dirHandler->close();
return FALSE; // Return false
}
/**
Delete($varId) --
Loops through the cache directory and
removes any cache files with the varId
specified in $varID
**/
function Delete($varId) {
$dirHandler = dir($this->cacheDir);
while ($file = $dirHandler->read()) {
if (preg_match("/cache.$varId.[0-9]/", $file)) {
unlink($this->cacheDir . $file); // Delete cache file
}
}
$dirHandler->close();
}
}
?>
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Usage Example
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include("class.cacher.php");
$cache = new Cacher;
$variable = $cache->Get("var1", 60); // 60 is the time out in seconds, default set inside source of object.
if (!$variable) {
/**
Cache file expired or doesn't exist.
Do something to get new result.
**/
$cache->Set("var1", $newresult);
$variable = $newresult;
}
echo $variable;
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