How Laravel generates a four-digit unique invitation code based on user ID

The following tutorial column will introduce to you how Laravel generates a four-digit unique invitation code based on the user ID. I hope it will be helpful to friends in need! Create a new file app/Services/InviteCodeService.php

<?php namespace App\Services;// 邀请码服务class InviteCodeService{

    protected $key,$num;
    public function __construct()
    {
        $this->key = 'abcdefghjkmnpqrstuvwxyz123456789';
        // 注意这个key里面不能出现数字0  否则当 求模=0 会重复的

        // 多少进制
        $this->num = strlen($this->key);
    }

    // 传递用户id生成唯一邀请码
    public function enCode(int $user_id)
    {

        $code = ''; // 邀请码
        while ($user_id > 0) { // 转进制
            $mod = $user_id % $this->num; // 求模

            $user_id = ($user_id - $mod) / $this->num;
            $code = $this->key[$mod] . $code;
        }

        $code = str_pad($code, 4, '0', STR_PAD_LEFT); // 不足用0补充
        return $code;
    }


    // 邀请码获取用户id  一般都不需要用到
    function deCode($code)
    {

        if (strrpos($code, '0') !== false)
            $code = substr($code, strrpos($code, '0') + 1);
        $len = strlen($code);
        $code = strrev($code);
        $user_id = 0;
        for ($i = 0; $i key, $code[$i]) * pow($this->num, $i);
        return $user_id;
    }}

Bind to the container

See what you like, if you don’t want to bind Just new \App\Services\InviteCodeService.

Editapp/Providers/AppServiceProvider.php

    use App\Services\InviteCodeService;
    public function register()
    {
        $this->app->singleton('invite_code',InviteCodeService::class);
    }

Test uniqueness

      $max_num = 200000;

        $codes = [];
        for ($i = 1; $i enCode($i);

        $i = 1;
        foreach ($codes as $code){
            $userId = app('invite_code')->deCode($code); // 邀请码获取用户id

            if( $userId != $i)
                dd("邀请码解密错误".$i);
            $i++;
        }

        $unique_count =  count(array_unique($codes));
        dd($unique_count);  // 不重复的总数

20w There is no duplication of data, and the invitation code solution

is also correct. Note

$this->key

0
1. cannot appear. $this->key There cannot be duplicate strings. For example:
abccd
2. c Repeat. ##About $this->key

##$this->key The order can be disrupted ,

// $this->key = 'abcdefghjkmnpqrstuvwxyz123456789'; // 没打乱的$this->key = 'kh8sjpdazetnmb5yw7rq4gc9fuv3216x'; // 打乱的

1. $this->key There is no limit to the length, but it is best not to be too short.

   For example,
abcd
2. : The largest

   user id is 4 to the third power (256) What will happen if it exceeds 256? The invitation code becomes only 5 digits... , not good-looking.
   For user experience, don’t add i
   

   o
3. l to the string

   $this->key These letters are easy to confuse users. i : l
   l : 1
   o : 0 (Of course 0
   cannot appear) is very similar.
   Ps

user id can be modulated .

ExampleAssume

That is 4-base.

For example: User ID

255

256 The invitation code is 5 digits.
500 The invitation code is 5 digits.
......(So if there is a limit on the number of invitation codes, you will know what to do if you are smart)

What is the maximum user ID with a 4-digit hexadecimal invitation code?

32^4 = 1048576

BullshitBecause I wanted to use the invitation code function, my first reaction was:

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