Program | Cache
Content cache output PEAR Cache
Next we begin to explore more commonly used caching techniques, which is also a key part of this article. First we use the cache package in pear. Pear can cache content in a file, in a database, or in memory, as an example of a file.
below is a PHP applet that does not use caching:
pear_content_cache1.php
<?php
echo "This is the content. <p> ";
echo "Current time is". Date (' M-d-y h:i:s A ', Time ()). "<BR>";
? >
The above program is very simple, now we add caching to it.
pear_content_cache2.php
<?php
require_once ' cache/output.php ';
//Set cache directory, must be writable
$cacheDir = './pear_cache ';
$cache = new Cache_output (' file ', array (' Cache_dir ' => $cacheDir));
//If the NoCache variable is empty, use the contents of the cache
//If you want to get the latest content, assign the value to the NoCache variable
if (Empty ($_request[' NoCache '))
{
//Create a unique cache ID
//Request +cookie Information
$cache _id = $cache->generateid (array (' URL ' => $_request, ' post ' =>$_post, ' cookies ' => $HTTP _cookie_vars));
}
Else
{
//Want to get the latest content, ID is empty
$cache _id = null;
}
//See cache ID corresponding to the cached content is available
if ($content = $cache->start ($cache _id))
{
//cache already exists, direct output, and end script
Echo $content;
exit ();
}
The content does not exist in the
//cache, generating new content and writing to the cache
echo "This is the content. <p> ";
echo "Current time is". Date (' M-d-y h:i:s A ', Time ()). "<BR>";
//write content to cache
echo $cache->end ();
? >
refresh these two files separately, you will find that the time in the line "current time is" in pear_content_cache1.php changes with the refresh, and the line in pear_content_cache2.php is unchanged. This is because pear_content_cache2.php uses a cache to store the content requested by the user in a static file. When the user requests it again, it outputs directly from the file without the need to dynamically generate the content with the program.
For pear_content_cache2.php, if the user wants to read the latest information, not the old information in the cache. Then you can use http://.../pear_content_cache2.php?nocache=1 to access it, which disables caching. Refresh and see, you will find that time will change.
summarize the use of the Pear content cache class:
1. Include the pear package to be aware of the set path.
2. Contains the cache class in output.php
require_once ' cache/output.php ';
3. Set Cache directory
$cacheDir = './pear_cache ';
Verify that the directory is writable. The cache data will be written to the subdirectory of this directory.
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