com_create_guid

(PHP 5, PHP 7, PHP 8)

com_create_guid — Genera un identificador único global (GUID)

Descripción

com_create_guid(): string|false

Genera un identificador único global (GUID).

Un GUID se genera de la misma manera que DCE UUID, excepto por el hecho de que la convención de Microsoft incluye el GUID en un paréntesis.

Parámetros

Esta función no tiene parámetros.

Valores devueltos

Devuelve el GUID, en forma de string, o false en caso de error.

Ver también

uuid_create() en la extensión PECL uuid

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User Contributed Notes 5 notes

down

Dave Pearson (dave at pds-uk dot com) ¶

9 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;
}
?>

down

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.

down

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));
}

down

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

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internmail (at the google mail).com ¶

5 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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