Output Caching with PHP - Output Buffering for Server Side Caching (
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Now, with this example in our hands, let’s see how we can use output buffering for server side caching. Let's implement a very simple demonstration, where the buffer content is stored as a file:
<?php
// check if there is a cached version
if ( file_exists( ‘cachefile.txt’ ) ) {
// if there is a cached version read content and display
readfile ( ‘cachefile.txt’ );
exit();
}
// if there is not a cached version start output buffering
ob_start();
// display some HTML ( this will be stored in the buffer )
?>
<html>
<head>
<title>Caching server output</title>
</head>
<body>
<h2>This page is a cached Page</h2>
</body>
</html>
<?php
$bufferContent = ob_get_contents();
// get buffer content
ob_end_flush();
// clean and display buffer content in the browser
$fp = fopen ( ‘cachefile.txt’ , ‘w’ ) or die ( ‘Error opening cache file’ );
// write buffer content to cache file
fwrite ( $fp , $bufferContent );
fclose( $fp );
?>
The output for the above script is the parsed HTML:
This page is a cached Page
The contents of the cache file ‘cachefile.txt’ is the same HTML included in the script:
<html>
<head>
<title>Caching server output</title>
</head>
<body>
<h2>This page is a cached Page</h2>
</body>
</html>
Let’s examine in detail what’s going on within the script:
First, the script checks to see if there is a cached version of the page, by determining if a cache file exists. If it does, it then reads the cache file and send the output to the browser. Otherwise, it starts a new output buffer and store some HTML on it to generate the cached version. Once this is done, it gets the buffer content and stores it in a variable ($bufferContent). Next, the buffer is cleared and the HTML is displayed to the user. Finally, the buffer content is written to the cache file.
Obviously, this script is very simple, but exposes in a nutshell the powerful caching capabilities that PHP has built-in, when used in conjunction with output buffering functions. Having all of this potential in our hands, the logical next step is caching different sections of a Web page. Web pages usually have a header section, body and a footer section. It would be good to apply these caching techniques accordingly to how frequently those generic sections are updated. We’re moving that way now.
| | Discuss Output Caching with PHP | | | | | | | The article deals with the basics of PHP Output Caching. Also, it shows some chunked... | | | | | |
For the sake of clarity and accuracy, where it reads $cachefile, should be... | | | | | | Too much editorialising, discussing history, something. After reading the first... | | | | | | Hello Sr.
Thank you for the comment. I'm sorry you didn't enjoy the article. That... | | | | | | I find it interesting that you didn't mention Smarty as a caching option. On top of... | | | | | | Hi David,
Thank you for the commnent. The interspered PHP is only for the... | | | | | | i am a beginner, just pure questions.
what's the point of using all the ob_start,... | | | | | | Yes , i like it and am using it long time ago , the benefit( my opinion) the cache... | | | | | | Hi,
I totally agree with you!
Alejandro Gervasio | | | | | | Hello,
This article is intented to be an introduction to PHP cache capabilities,... | | | | | | I disagree, the beginning of the article made the subject and benefit quite... | | | | | | David says he'd like to see the HTML and PHP in separate files. I've been reading a... | | | | | | Well, Smarty is an excellent template system (and includes more capabilities too)... | | | | | | im kinda new to caching and I was trying the original script..im sorry if it looks... | | | | | | ok im replying to myself, erm it's late here and i hate these kinda glitches that... | | | | | | Is it possible to implement this process in the phpBB code for discussion... | | | | | | Thank you for posting your comment here. With regard to your question, unfortunately... | | | | | | Thanks for the very prompt reply! I guess I should just give up then....have spent... | | | | | | I'd like thank you for posting your feedback here. With reference to your problem,... | | | | | | Good Tutorial thk,
just a little correct though
It would probly not be long for U... | | | | | | Hi Sig again,
Thank you fo pointing out the missing parenthesis on the code. It... | | | | | | thnX a lot Alejandro for this amazing article.
when I was read it ,I could see the... | | | | | | Thank you for the kind comments on my PHP article and your excellent suggestion on... | | | | | | There's a straight forward explanation why there must be files. Caching is supposed... | | | | | | Thanks for the great contribution. That’s exactly the purpose in caching PHP... | | | | | | Hey, this is a great article, really made caching seem a simple affair! I am... | | | | | | Thanks for the kind words on my PHP caching article. Regarding your questions,... | | | | | | Thanks for your article. This gave me a good view of how Caching works, had no idea... | | | | | | >>> Post your comment now! | | | | | |
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