com_create_guid
(PHP 5)
com_create_guid — Generate a globally unique identifier (GUID)
Описание
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.
Возвращаемые значения
Returns the GUID as a string.
Смотрите также
- uuid_create() in the PECL uuid extension
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения только для Windows
- COM и .Net (Windows)
- com_create_guid
- com_event_sink
- com_get_active_object
- com_load_typelib
- com_message_pump
- com_print_typeinfo
- variant_abs
- variant_add
- variant_and
- variant_cast
- variant_cat
- variant_cmp
- variant_date_from_timestamp
- variant_date_to_timestamp
- variant_div
- variant_eqv
- variant_fix
- variant_get_type
- variant_idiv
- variant_imp
- variant_int
- variant_mod
- variant_mul
- variant_neg
- variant_not
- variant_or
- variant_pow
- variant_round
- variant_set_type
- variant_set
- variant_sub
- variant_xor
Коментарии
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.
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));
}
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
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 $guidv4;
}
?>
function create_guid() { // Create GUID (Globally Unique Identifier)$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;
}