com_create_guid

(PHP 5, PHP 7, PHP 8)

com_create_guid — Generar un identificador único globalmente (GUID)

Descripción

com_create_guid(): string

Genera un identificador único globalmente (GUID: Globally Unique Identifier).

Un GUID es generado de la misma manera que el DCE UUID, excepto que la convención de Microsoft encierra un GUID entre llaves.

Valores devueltos

Devuelve el GUID como cadena.

Ver también

uuid_create() en la extensión uuid de PECL

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User Contributed Notes 6 notes

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Alix Axel ¶

13 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.

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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;
}
?>

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pavel.volyntsev(at)gmail ¶

8 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));
}

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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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indrora ¶

8 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

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-4

rogervila dot es ¶

4 years ago


I implemented a com_create_guid implementation for systems that do not support it as a Composer package in order to keep it separated from my applications 

https://github.com/rogervila/com_create_guid

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