How to generate a recommendation code that is absolutely unique and not easily guessed

Don't go in the database check

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Don't go in the database check

function makeCode($t) {  $time = $t.mt_rand(10,99); // 要是觉得不够可以加上线程ID等。  $ce = $time[9];  $xy = array();  $xy[0] = array('A','F','D','X','G','H','K','U','P','Y','W','P');  $xy[1] = array('R','G','H','P','X','D','Y','U','K','F','S','Z');  // ... 不重复的序列即可  $xy[9] = array('S','K','T','U','E','Q','V','G','R','X','C','J');  $rb = '';  for ($i = 12;$i--;) {    $rb .= $xy[$ce][$time[$i]];  }  return $rb;}makecode(time())

For 绝对唯一 speaking please useUUID
For example, you are using a Linux system that can

echo file_get_contents('/proc/sys/kernel/random/uuid');// 输出: 6c509fc7-328b-4d82-9af8-60c44e7b84b4

When you get a unique string like this, you can do whatever you want to do with it, such as intercepting the length you need.
PHP generates UUID in a number of ways, it is simple to use, also recommended a class library link

If it is a general recommendation code actually does not need to make very complicated, unless you have a lot of user volume. If it's a general company, I think it's enough.

echo bin2hex(openssl_random_pseudo_bytes(16));// 输出: 5a8a80e06ffe44fd0a6931707a26f0cc

Likewise, you are free to intercept

http://hashids.org/

Add a check code to it.

