php 原子地将一行附加到文件并在文件不存在时创建它
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Atomically appending a line to a file and creating it if it doesn't exist
提问by Jaka Jan?ar
I'm trying to create a function (for purposes of logging)
我正在尝试创建一个函数（用于日志记录）
append($path, $data)
that
那
- creates $file if it doesn't exist and
- atomically appends $data to it.
- 如果 $file 不存在，则创建它，并且
- 原子地将 $data 附加到它。
It has to
它必须
- support high concurrency,
- support long strings and
- be as performant as possible.
- 支持高并发，
- 支持长字符串和
- 尽可能提高性能。
So far the best attempt is:
到目前为止，最好的尝试是：
function append($file, $data)
{
// Ensure $file exists. Just opening it with 'w' or 'a' might cause
// 1 process to clobber another's.
$fp = @fopen($file, 'x');
if ($fp)
fclose($fp);
// Append
$lock = strlen($data) > 4096; // assume PIPE_BUF is 4096 (Linux)
$fp = fopen($file, 'a');
if ($lock && !flock($fp, LOCK_EX))
throw new Exception('Cannot lock file: '.$file);
fwrite($fp, $data);
if ($lock)
flock($fp, LOCK_UN);
fclose($fp);
}
It works OK, but it seems to be a quite complex. Is there a cleaner (built-in?) way to do it?
它工作正常，但它似乎是一个相当复杂的。有更清洁的（内置的？）方法吗？
回答by FtDRbwLXw6
PHP already has a built-in function to do this, file_put_contents(). The syntax is:
PHP 已经有一个内置函数来执行此操作，file_put_contents()。语法是：
file_put_contents($filename, $data, FILE_APPEND);
Note that file_put_contents()will create the file if it does not already exist (as long as you have file system permissions to do so).
请注意，file_put_contents()如果该文件尚不存在，则将创建该文件（只要您具有文件系统权限即可）。
回答by catalint
using PHP's internal function http://php.net/manual/en/function.file-put-contents.php
使用 PHP 的内部函数http://php.net/manual/en/function.file-put-contents.php
file_put_contents($file, $data, FILE_APPEND | LOCK_EX);
FILE_APPEND => flag to append the content to the end of the file
FILE_APPEND => 将内容附加到文件末尾的标志
LOCK_EX => flag to prevent anyone else writing to the file at the same time (Available since PHP 5.1)
LOCK_EX => 标志以防止其他人同时写入文件（自 PHP 5.1 起可用）
