com_create_guid

    (PHP 5, PHP 7, PHP 8)

    com_create_guid — Generate a globally unique identifier (GUID)

    Description

    com_create_guid(): string|false

    Generates a Globally Unique Identifier (GUID).

    A GUID is generated in the same way as DCE UUID's, except that the Microsoft convention is to enclose a GUID in curly braces.

    Parameters

    This function has no parameters.

    Return Values

    Returns the GUID as a string, or false on failure.

    See Also

    • uuid_create() in the PECL uuid extension

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    User Contributed Notes 5 notes

    up
    34
    Dave Pearson (dave at pds-uk dot com)
    8 years ago
    Here's my final version of a GUIDv4 function (based on others work here) that should work on all platforms and gracefully fallback to less cryptographically secure version if others are not supported...

    <?php
    /**
    * Returns a GUIDv4 string
    *
    * Uses the best cryptographically secure method
    * for all supported pltforms with fallback to an older,
    * less secure version.
    *
    * @param bool $trim
    * @return string
    */
    function GUIDv4 ($trim = true)
    {
    // Windows
    if (function_exists('com_create_guid') === true) {
    if (    $trim === true)
    return     trim(com_create_guid(), '{}');
    else
    return     com_create_guid();
    }

    // OSX/Linux
    if (function_exists('openssl_random_pseudo_bytes') === true) {
    $data = openssl_random_pseudo_bytes(16);
    $data[6] = chr(ord($data[6]) & 0x0f | 0x40); // set version to 0100
    $data[8] = chr(ord($data[8]) & 0x3f | 0x80); // set bits 6-7 to 10
    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
    }

    // Fallback (PHP 4.2+)
    mt_srand((double)microtime() * 10000);
    $charid = strtolower(md5(uniqid(rand(), true)));
    $hyphen = chr(45); // "-"
    $lbrace = $trim ? "" : chr(123); // "{"
    $rbrace = $trim ? "" : chr(125); // "}"
    $guidv4 = $lbrace.
    substr($charid, 0, 8).$hyphen.
    substr($charid, 8, 4).$hyphen.
    substr($charid, 12, 4).$hyphen.
    substr($charid, 16, 4).$hyphen.
    substr($charid, 20, 12).
    $rbrace;
    return     $guidv4;
    }
    ?>
    up
    39
    Alix Axel
    14 years ago
    The phunction PHP framework (http://sourceforge.net/projects/phunction/) uses the following function to generate valid version 4 UUIDs:

    <?php

    function GUID()
    {
    if (    function_exists('com_create_guid') === true)
    {
    return     trim(com_create_guid(), '{}');
    }

    return     sprintf('%04X%04X-%04X-%04X-%04X-%04X%04X%04X', mt_rand(0, 65535), mt_rand(0, 65535), mt_rand(0, 65535), mt_rand(16384, 20479), mt_rand(32768, 49151), mt_rand(0, 65535), mt_rand(0, 65535), mt_rand(0, 65535));
    }

    ?>

    The output generated by the sprintf() and mt_rand() calls is identical to com_create_guid() results.
    up
    28
    pavel.volyntsev(at)gmail
    9 years ago
    Use more cryptographically strong algorithm to generate pseudo-random bytes and format it as GUID v4 string

    function guidv4()
    {
    if (function_exists('com_create_guid') === true)
    return trim(com_create_guid(), '{}');

    $data = openssl_random_pseudo_bytes(16);
    $data[6] = chr(ord($data[6]) & 0x0f | 0x40); // set version to 0100
    $data[8] = chr(ord($data[8]) & 0x3f | 0x80); // set bits 6-7 to 10
    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
    }
    up
    11
    indrora
    9 years ago
    If you're going to generate random UUIDs, at least make them conform:

    * The uppermost byte of the third stanza must be 4
    * the uppermost byte of the fourth stanza may be any of (8 9 a b)

    see also: The wikipedia page for UUIDs: https://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_.28random.29
    up
    0
    internmail (at the google mail).com
    4 years ago
    function create_guid() { // Create GUID (Globally Unique Identifier)
    $guid = '';
    $namespace = rand(11111, 99999);
    $uid = uniqid('', true);
    $data = $namespace;
    $data .= $_SERVER['REQUEST_TIME'];
    $data .= $_SERVER['HTTP_USER_AGENT'];
    $data .= $_SERVER['REMOTE_ADDR'];
    $data .= $_SERVER['REMOTE_PORT'];
    $hash = strtoupper(hash('ripemd128', $uid . $guid . md5($data)));
    $guid = substr($hash, 0, 8) . '-' .
    substr($hash, 8, 4) . '-' .
    substr($hash, 12, 4) . '-' .
    substr($hash, 16, 4) . '-' .
    substr($hash, 20, 12);
    return $guid;
    }
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