com_create_guid

(PHP 5, PHP 7)

com_create_guid — Generate a globally unique identifier (GUID)

说明

string com_create_guid ( void )

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.

返回值

Returns the GUID as a string.

参见

uuid_create() in the PECL uuid extension

用户评论:

[#1] indrora [2015-11-08 07:09:52]

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

[#2] pavel.volyntsev(at)gmail [2015-08-27 12:37:47]

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));
}

[#3] mark at briley dot com [2015-03-30 15:34:10]

I made a mistake on my previous note.  I used rtrim instead of just trim to take off the curly brackets.  Here is my note again - or please change the RTRIM to just TRIM in my previous note.  Thanks!  :-)

Kristof_Polleunis at yahoo dot com has an excellent function for obtaining a GUID but I believe it can be improved by checking for whether or not to remove the curly braces so the programmer who uses it doesn't have to do this.  Here is the improved function:

<?php # #   Taken from the PHP documentation website. # #   Kristof_Polleunis at yahoo dot com # #   A guid function that works in all php versions: #   MEM 3/30/2015 : Modified the function to allow someone #       to specify whether or not they want the curly #       braces on the GUID. # function guid( $opt = true ){       //  Set to true/false as your default way to do this.     if( function_exists('com_create_guid') ){         if( $opt ){ return com_create_guid(); }             else { return trim( com_create_guid(), '{}' ); }         }         else {             mt_srand( (double)microtime() * 10000 );    // optional for php 4.2.0 and up.             $charid = strtoupper( md5(uniqid(rand(), true)) );             $hyphen = chr( 45 );    // "-"             $left_curly = $opt ? chr(123) : "";     //  "{"             $right_curly = $opt ? chr(125) : "";    //  "}"             $uuid = $left_curly                 . substr( $charid, 0, 8 ) . $hyphen                 . substr( $charid, 8, 4 ) . $hyphen                 . substr( $charid, 12, 4 ) . $hyphen                 . substr( $charid, 16, 4 ) . $hyphen                 . substr( $charid, 20, 12 )                 . $right_curly;             return $uuid;             } } ?>

As the comments say - set the incoming option ($opt) to either TRUE or FALSE depending upon whether you want the curly braces to always show up or not.  If you need to obtain a GUID in the other way - all you have to do is to send the opposite value to the function.

[#4] Alix Axel [2010-08-16 15:59:39]

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.

[#5] Kristof_Polleunis at yahoo dot com [2005-04-28 08:16:42]

A guid function that works in all php versions:

<?php function guid(){ if (function_exists('com_create_guid')){ return com_create_guid(); }else{ mt_srand((double)microtime()*10000);//optional for php 4.2.0 and up. $charid = strtoupper(md5(uniqid(rand(), true))); $hyphen = chr(45);// "-" $uuid = chr(123)// "{" .substr($charid, 0, 8).$hyphen .substr($charid, 8, 4).$hyphen .substr($charid,12, 4).$hyphen .substr($charid,16, 4).$hyphen .substr($charid,20,12) .chr(125);// "}" return $uuid; } } echo guid(); ?>