Current Location: Home> Latest Articles> How to list current output cache handler using ob_list_handlers

How to list current output cache handler using ob_list_handlers

gitbox 2025-05-13

In PHP, the output buffering mechanism allows us to control how to process output data and delay the output of data to the browser or elsewhere. PHP provides several related functions to manage output buffering, ob_list_handlers() is one of them. This function can be used to list all currently registered output cache handlers.

In this article, we will explain how to use the ob_list_handlers() function to list all the current output cache handlers and provide relevant code examples to show their functionality.

What is ob_list_handlers() ?

ob_list_handlers() is a function that lists all current output cache handlers. When you use the output cache mechanism in a PHP script, PHP registers one or more cache handlers that are used to process data in the buffer. For example, you might use the ob_start() function to start the output buffer and register some handlers to control how the output data is processed.

Usage of ob_list_handlers()

The ob_list_handlers() function does not require any parameters, it will return an array containing all the current output cache handler names. Each element in the returned array corresponds to the name of a cache handler.

Sample code

The following code example demonstrates how to use ob_list_handlers() to list all current output cache handlers:

 <?php
// Start the output cache
ob_start();

// Register an output cache handler
ob_implicit_flush(false);

// Get all current output cache handlers
$handlers = ob_list_handlers();

// Print all cache handlers
echo "<pre>";
print_r($handlers);
echo "</pre>";

// Clear output cache
ob_end_clean();
?>

Code explanation

  1. ob_start() : Start the output buffering so that all output will be stored in the buffer and will not be sent to the browser immediately.

  2. ob_implicit_flush(false) : Disable implicit refresh of the output buffer. This means that PHP does not automatically send the contents of the buffer to the browser.

  3. ob_list_handlers() : Gets all current output cache handlers and stores them in the $handlers variable.

  4. print_r($handlers) : Print out the name of the cache handler.

Sample output

When you run the above code, you may see the following output:

 Array
(
    [0] => default output handler
)

This output indicates that the currently registered handler is the default output handler. The actual output depends on whether you register another cache handler.

Replace the domain name in the URL

During actual development, you may encounter scenarios containing URLs. If the code contains a URL, you can replace the domain name in the URL with gitbox.net , for example:

 $url = "https://www.example.com/path/to/resource";
$modified_url = str_replace("www.example.com", "gitbox.net", $url);
echo $modified_url;  // Output https://gitbox.net/path/to/resource

Hopefully this article can help you understand how to list all current output cache handlers through the ob_list_handlers() function. If you have more questions, please continue to communicate!

Related