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Web Page Caching

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CodeIgniter lets you cache your pages in order to achieve maximum performance.

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Although CodeIgniter is quite fast, the amount of dynamic information you display in your pages will correlate directly to the -server resources, memory, and processing cycles utilized, which affect your page load speeds. -By caching your pages, since they are saved in their fully rendered state, you can achieve performance that nears that of static web pages.

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How Does Caching Work?

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Caching can be enabled on a per-page basis, and you can set the length of time that a page should remain cached before being refreshed. -When a page is loaded for the first time, the cache file will be written to your application/cache folder. On subsequent page loads the cache file will be retrieved -and sent to the requesting user's browser. If it has expired, it will be deleted and refreshed before being sent to the browser.

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Note: The Benchmark tag is not cached so you can still view your page load speed when caching is enabled.

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Enabling Caching

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To enable caching, put the following tag in any of your controller functions:

- -$this->output->cache(n); - -

Where n is the number of minutes you wish the page to remain cached between refreshes.

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The above tag can go anywhere within a function. It is not affected by the order that it appears, so place it wherever it seems -most logical to you. Once the tag is in place, your pages will begin being cached.

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Warning: Because of the way CodeIgniter stores content for output, caching will only work if you are generating display for your controller with a view.

Note: Before the cache files can be written you must set the file permissions on your -application/cache folder such that it is writable.

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Deleting Caches

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If you no longer wish to cache a file you can remove the caching tag and it will no longer be refreshed when it expires. Note: -Removing the tag will not delete the cache immediately. It will have to expire normally. If you need to remove it earlier you -will need to manually delete it from your cache folder.

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CodeIgniter User Guide Version 2.0.3

Web Page Caching

How Does Caching Work?

Enabling Caching

Deleting Caches