Is there any Value in PHP which is unique for each system

Question

In PHP, is there any way to get a value that is unique to the system it is running on?

Ideally, I would like it to be a sort of random string that stays the same on the system that is running on, but is different on other systems.

I need one that I don't have to store in an separate file/DB and is easily available on each script.

PHP doesn't have a built in UUID generator that I know about, but [`uniqid()`](http://php.net/manual/en/function.uniqid.php) used in conjunction with unique hostnames may do the job for you. — Michael Berkowski, Nov 21 '14 at 14:42
But as the manual cautions, uniqid() is not high-entropy and not to be used for any crypto purpose. Instead, http://php.net/manual/en/function.openssl-random-pseudo-bytes.php — Michael Berkowski, Nov 21 '14 at 14:43
If you are looking for unique value for user computer, than it's not related to PHP, because PHP parameters comes from server OS/system. — Justinas, Nov 21 '14 at 14:47
`uniqid()` is not a constant value it returns different values each time. — Shubanker, Nov 21 '14 at 14:54
I would personally look up the UUID of the system like http://stackoverflow.com/questions/328936/getting-a-unique-id-from-a-unix-like-system — PeeHaa, Nov 21 '14 at 14:55

score 1 · Answer 1 · edited Apr 13 '17 at 12:36

1

Create your own random value (with uniqid for example) and put it to environment variable. For user, apache or nginx. Or just define it in your php file.

edited Apr 13 '17 at 12:36

Community

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answered Nov 21 '14 at 14:58

sectus

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score 0 · Answer 2 · answered Nov 21 '14 at 14:46

Yes -

Ultimately, you want gethostname()

And if you do :

echo md5($_SERVER['SERVER_ADDR'].gethostname());

Then you will have a unique string that pertains only to that server

But, there are plenty of other values that will be unique-ish

Try :

<?php 

print_r($_SERVER); 

?>

And you should find several values that are like what you are looking for.

Such as:

 [SERVER_SOFTWARE] => nginx/1.4.6

 [SERVER_ADDR] => 123.456.789.909

Then, there are also some predefined constants that may hold what you want -

<?php

print_r(get_defined_constants()); 


?>

Which has things like:

[PHP_VERSION] => 5.5.9-1ubuntu4.5
[PHP_MAJOR_VERSION] => 5
[PHP_MINOR_VERSION] => 5
[PHP_RELEASE_VERSION] => 9
[PHP_EXTRA_VERSION] => -1ubuntu4.5
[PHP_VERSION_ID] => 50509

And while these values will be identical on servers that are running the same software stack -- it is often not likely that these values will match perfectly... However, your best bet for unique ID would be the IP address + the host name-

Well this could be the perfect solution for any real website but I am looking for an solution which should work on local server too and also should be unpredictable such as `gethostname()`. — Shubanker, Nov 21 '14 at 14:51

score -4 · Answer 3 · edited Nov 21 '14 at 15:02

-4

You could generate the uniqid() append hostname, then hash it with something like md5 or sha-256

edited Nov 21 '14 at 15:02

Shubanker

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answered Nov 21 '14 at 14:48

tylerlindell

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Is there any Value in PHP which is unique for each system

3 Answers3