PHP function to calculate the MD5 checksum of a file

PHP File Handling: Exercise-18 with Solution

Write a PHP function to calculate the MD5 checksum of a file.

Sample Solution:

PHP Code :

<?php
function calculateFileChecksum($filename) {
    try {
        if (!file_exists($filename)) {
            throw new Exception("File does not exist.");
        }

        $checksum = md5_file($filename);

        if ($checksum === false) {
            throw new Exception("Error calculating MD5 checksum.");
        }

        return $checksum;
    } catch (Exception $e) {
        echo "An error occurred: " . $e->getMessage();
    }
}

// Usage:
$filename = "i:/test.txt";
$checksum = calculateFileChecksum($filename);

echo "MD5 Checksum: " . $checksum . "\n";
?>

Sample Output:

MD5 Checksum: 4271622bc79aba1829f5612e0400a034

Explanation:

In the above exercise -

• The function calculateFileChecksum($filename) takes the filename as input.
• First, we check if the file exists using file_exists(). If the file does not exist, we throw an exception with the error message "File does not exist."
• We then use the md5_file() function to calculate the MD5 checksum of the file. This function reads the file contents and computes the MD5 hash value.
• If there is an error calculating the MD5 checksum, we throw an exception with the error message "Error calculating MD5 checksum."
• Finally, we return the computed MD5 checksum from the function.

Flowchart:

PHP Code Editor:

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