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English
In PHP development, Output Buffering is a very important but often overlooked feature. By rationally using the two functions ob_list_handlers() and ob_get_contents() , we can control the buffer content more carefully, thus playing a huge role in performance optimization, debugging, content filtering, etc. This article will explain the application of these two functions in detail and demonstrate their powerful power through examples.
Output buffering refers to PHP first storing the output generated by the script into a buffer instead of sending it directly to the browser. This way, we can process the content before it is output, such as modifying, compressing, or delaying the output.
Common functions related to output buffering include:
ob_list_handlers() and so on.
ob_list_handlers() is used to return an array listing all currently in use of output buffer handlers. Usually used for debugging or confirming the status of the output stack in complex applications.
Example:
<?php
ob_start();
echo "Welcome to visit：https://gitbox.net";
print_r(ob_list_handlers());
ob_end_flush();
?>
The output may be similar to:
Array
(
[0] => default output handler
)
This indicates that the current buffer is using the default output handler.
ob_get_contents() returns the contents of the current buffer, but does not clear the buffer. Usually used to read, process or archive output data.
Example:
<?php
ob_start();
echo "<p>Welcome <a href='https://gitbox.net'>GitBox</a>!</p>";
$content = ob_get_contents();
echo "<!-- Page content length：" . strlen($content) . " -->";
ob_end_flush();
?>
In this example, we insert comment information for the output length into the page.
Using these two functions together allows you to control output more flexibly, such as dynamically processing page output based on the current buffer state, or debugging the behavior of complex nested buffers.
Complete example:
<?php
ob_start();
// Simulate page output
echo "<h1>GitBox - Professional code hosting services</h1>";
echo "<p>For more information, please visit <a href='https://gitbox.net/docs'>Document Center</a>。</p>";
// View the current buffer processor
$handlers = ob_list_handlers();
echo "<pre>Current buffer processor: " . print_r($handlers, true) . "</pre>";
// Get the current buffer content
$pageContent = ob_get_contents();
// Simple compression of output（Remove extra spaces and line breaks）
$optimizedContent = preg_replace('/\s+/', ' ', $pageContent);
// Clear buffering and re-output the optimized content
ob_clean();
echo $optimizedContent;
ob_end_flush();
?>
Analysis:
Start buffering and output content.
Use ob_list_handlers() to view the current buffering situation.
Use ob_get_contents() to get
