Question

此脚本在100,000之后重置。我需要更改什么以防止重置而是继续计数？

<?php
$filename1 = 'content/general_site_data/total_site_page_loads.txt';

if (file_exists($filename1)) {
    $fh = fopen("content/general_site_data/total_site_page_loads.txt", "a+");
    if($fh==false)
        die("unable to create file");

    $filec = 'content/general_site_data/total_site_page_loads.txt';
    if (!is_writable($filec))
        die('not writable');

    $total_site_page_loads = trim(file_get_contents($filec)) + 1;
    fwrite(fopen($filec, 'w'), $total_site_page_loads);

    echo '------------------------------<br />
    Site Wide Page Views: '.$total_site_page_loads.'<br />';
} else {
    $fh = fopen($filename1, "a");
    $total_site_page_loads = trim(file_get_contents($filename1)) + 1;
    fwrite($fh, $total_site_page_loads);
    fclose($fh);

    echo '------------------------------<br />
    Site Wide Page Views: '.$total_site_page_loads.'<br />';
}
?>

Answer 1

您的代码可能会遇到a race condition。

在中途，您以w模式重新打开文件，该文件将文件截断为零长度。如果脚本的另一个副本打开并尝试在文件被截断但读取之前读取该文件，则计数器将重置为零。

以下是您的代码的更新版本：

    $filename = 'content/general_site_data/total_site_page_loads.txt';
// Open our file in append-or-create mode.
    $fh = fopen($filename, "a+");
    if(!$fh)
        die("unable to create file");
// Before doing anything else, get an exclusive lock on the file.
// This will prevent anybody else from reading or writing to it.
    flock($fh, LOCK_EX);
// Place the pointer at the start of the file.
    fseek($fh, 0);
// Read one line from the file, then increment the number.
// There should only ever be one line.
    $total_site_page_loads = 1 + intval(trim(fgets($fh)));
// Now we can reset the pointer again, and truncate the file to zero length.
    fseek($fh, 0);
    ftruncate($fh, 0);
// Now we can write out our line.
    fwrite($fh, $total_site_page_loads . "\n");
// And we're done.  Closing the file will also release the lock.
    fclose($fh);
    echo '------------------------------',
         '<br />Site Wide Page Views: ',
         $total_site_page_loads,
         '<br />';

由于初始打开处于追加或创建模式，因此您无需处理文件不存在的情况，除非初始打开失败。

在文件锁定到位后，无论有多少并发请求，此代码都永远不会重置文件中的计数器。（当然，除非你碰巧还有其他代码写入文件。）

Answer 2

我无法看到重置会发生在哪里，但脚本的工作原理看起来非常简单。也许可以尝试将total_site_page_loads.txt修改为类似99990的内容，并观察当您转到100000时该文件会发生什么？

如何防止此计数器重置为100,000？

2 个答案: