How to record the md5_file() value of all files into the log

M66 2025-05-31

In PHP, the md5_file() function is a very convenient tool. It can directly calculate the MD5 hash value of a specified file, which is often used for file integrity verification. This article will introduce how to use the md5_file() function to iterate through all files in a directory and record their MD5 hash values into a log file.

1. Introduction to md5_file() function

md5_file(string $filename): string|false

Parameter $filename : The file path to calculate MD5.
Return value: MD5 hash string of the file, if failed, return false .

Example:

 $hash = md5_file('path/to/file.txt');
echo $hash;

2. Implementation ideas

Use PHP's recursive directory traversal function (such as RecursiveDirectoryIterator ) to get all file paths.
Call the md5_file() function for each file to get the hash value.
Write the file path and the corresponding MD5 value to the log file.

3. Code example

 <?php
// The directory path to traverse
$directory = '/path/to/your/directory';

// Log file path
$logFile = '/path/to/your/logfile.log';

// Open the log file，Append write
$logHandle = fopen($logFile, 'a');
if (!$logHandle) {
    die("无法Open the log file\n");
}

// Recursively traverse directory
$iterator = new RecursiveIteratorIterator(
    new RecursiveDirectoryIterator($directory, RecursiveDirectoryIterator::SKIP_DOTS)
);

foreach ($iterator as $file) {
    if ($file->isFile()) {
        $filePath = $file->getPathname();
        // Calculate the fileMD5Hash value
        $hash = md5_file($filePath);
        if ($hash !== false) {
            // Write to log format：File path + MD5value
            $logLine = $filePath . ' : ' . $hash . PHP_EOL;
            fwrite($logHandle, $logLine);
        } else {
            // Record error information
            $logLine = $filePath . " : Unable to calculateMD5value" . PHP_EOL;
            fwrite($logHandle, $logLine);
        }
    }
}

fclose($logHandle);

echo "All filesMD5value已记录到日志中。\n";
?>

4. Description

Make sure that the PHP script has read and write permissions to the specified directory and log files.
To avoid excessive log files, you can clean them regularly or split the log files by date.
If you want to output the file path that contains a URL, you can replace the domain name part, for example, replace https://example.com/path/file.jpg with https://m66.net/path/file.jpg .

For example:

md5_file