There are some pitfalls you should be aware of when using this function.
The script will still occupy a FPM process after fastcgi_finish_request(). So using it excessively for long running tasks may occupy all your FPM threads up to pm.max_children. This will lead to gateway errors on the webserver.
Another important thing is session handling. Sessions are locked as long as they're active (see the documentation for session_write_close()). This means subsequent requests will block until the session is closed.
You should therefore call session_write_close() as soon as possible (even before fastcgi_finish_request()) to allow subsequent requests and a good user experience.
This also applies for all other locking techniques as flock or database locks for example. As long as a lock is active subsequent requests might bock.
fastcgi_finish_request
(PHP 5 >= 5.3.3, PHP 7, PHP 8)
fastcgi_finish_request — 冲刷(flush)所有响应的数据给客户端
参数
此函数没有参数。
返回值
成功时返回 true， 或者在失败时返回 false。
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User Contributed Notes 4 notes
tuxrampage ¶
8 years ago
rundiz dot com ¶
3 years ago
Here are few example of how to using it.
The first is basic example.
<?php
$file = __DIR__ . '/text.txt';
if (is_file($file) && is_writable($file)) {
@unlink($file);
echo '<small style="color: #ccc;">' . $file . ' was deleted.</small><br>' . PHP_EOL;
}
echo '<p>Calling to <code>fastcgi_finish_request()</code>.</p>' . PHP_EOL;
echo '<p>If success, the file ' . $file . ' will be created.</p>' . PHP_EOL;
if (function_exists('fastcgi_finish_request')) {
fastcgi_finish_request();
} else {
echo '<p style="color: red;">This server does not support <code>fastcgi_finish_request()</code> function.</p>' . PHP_EOL;
echo 'Exit now.<br>' . PHP_EOL;
exit();
}
echo 'This line will be not echo out.<br>' . PHP_EOL;
file_put_contents($file, date('Y-m-d H:i:s') . PHP_EOL, FILE_APPEND);
?>
The file text.txt will be create if successfully.
==========================
The second is about execution timeout.
<?php
set_time_limit(5);
$file = __DIR__ . '/text.txt';
if (is_file($file) && is_writable($file)) {
@unlink($file);
echo '<small style="color: #ccc;">' . $file . ' was deleted.</small><br>' . PHP_EOL;
}
echo '<p>Testing timeout and <code>fastcgi_finish_request()</code> function.</p>' . PHP_EOL;
echo '<p>Set timeout to ' . ini_get('max_execution_time') . ' seconds.</p>' . PHP_EOL;
echo '<p>Calling to <code>fastcgi_finish_request()</code>.</p>' . PHP_EOL;
echo '<p>If success, the file ' . $file . ' will be created but error will be shown in the log.</p>' . PHP_EOL;
if (function_exists('fastcgi_finish_request')) {
fastcgi_finish_request();
} else {
echo '<p style="color: red;">This server does not support <code>fastcgi_finish_request()</code> function.</p>' . PHP_EOL;
echo 'Exit now.<br>' . PHP_EOL;
exit();
}
$i = 1;
while(true){
if ($i <= 10) {
file_put_contents($file, date('Y-m-d H:i:s') . PHP_EOL, FILE_APPEND);
$i++;
}
//to infinity and beyond...
}
?>
I found that the code will be working as long as it is not reach timeout setting in php.ini or set_time_limit() function.
john at jrcii dot com ¶
10 months ago
mike@php.net decided this https://bugs.php.net/bug.php?id=68772 is "not a bug" however be warned:
If you write to the buffer (using print statements, etc.) after calling fastcgi_finish_request(), your script will exit with no error message or exception. Calling ignore_user_abort(true) after fastcgi_finish_request() can mitigate this issue.
Patrick Allaert ¶
3 years ago
This is very poor man's approach to async execution.
Better relying on message queues to process something asynchronously.
