• Saving data to a file with PHP

    Feb 24 2008

    Lately, I've been skipping using MySQL in situations where I just want to store a few variables, like configuration options, and don't necessarily want the hassle of setting up a database.

    You can easily store data to a file using serialize and unserialize to turn a PHP object into a string, and then read and write the string in a file.

    Here are a few functions that do just that:

    function get_data($filename) {
        // create file if it doesn't exist
        if (!file_exists($filename)) {
        return unserialize(file_get_contents($filename));
    function get_option($filename, $key) {
        $data = get_data($filename);
        return $data[$key];
    function set_option($filename, $key, $value) {
        $data = get_data($filename);
        $data[$key] = $value;
        // write to disk
        $fp = fopen($filename, 'w');
        fwrite($fp, serialize($data));
    // probably should put somewhere off the web root
    $config = '../config.dat';
    set_option($config, 'width', 1024);
    echo get_option($config, 'width'); // will echo 1024

    So there you have it. Feel free to use or modify this code as much as you like. If anyone has an idea for rewriting it to be cleaner, please share in the comments.

  • Comments

    1. Ed Eliot at 6:03pm on February 24, 2008

    It might be an idea to cache reading of options and buffer writing. That way you won't potentially hit the file multiple times on a single request.

    I'd suggest wrapping the functions in a class to make this a bit easier to achieve.

    2. Harmen Janssen at 6:53pm on February 24, 2008

    Make sure to familiarize yourself with the __sleep and __wakeup methods when serializing objects (http://php.net/__sleep)!

    Also, for an object oriented solution, you might be interested in the File and Cache classes I've written (http://whatphp.net/class.php?package=util/FileSystem/File/1.0&class=File&view=api and http://whatphp.net/class.php?class=Cache&package=util/Cache/1.0)

    3. Handan Daily at 11:16pm on March 25, 2008

    jquery is great!

    4. Handan Daily at 11:17pm on March 25, 2008

    your article chinese version


    5. Someone at 9:29pm on May 7, 2008

    Pretty good idea, I'll have plenty of uses for it.

    6. Stephen Mann at 9:57am on May 28, 2010

    Thanks - this is exactly what I need.

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