Thinkphp+redis realizes simple lottery

Redis Collection Introduction

Redis Set data type of , Very powerful . Speaking of assembly , You may think of the set in high school mathematics . In fact, they meant the same thing .Redis Many strings can be stored in the set （ Elements ）,Redis Most support 2 Of 32 The power minus 1 Elements , But the elements in the set are unique , There will be no repetition . Just like set in Mathematics ,Redis Also supports intersection , Union and subtraction .

It can complete many interesting functions . The most common is the tag function , Probably A The user's tag has “ Comic ”、” motion “、” Secondary yuan “,B The user's tag has ” motion “、” tourism “、” Basketball “. that , Use the union of sets , We can know what their common label is . in addition , When the system knows the user's label , You can recommend relevant advertisements or products to them . besides , It can also realize many interesting functions . today , Let's see how to use it Reids Realize the lottery function .

sRandMember、sPop

The functions of these two commands are very similar , All return an element value from the collection . The difference is ,sRandMember The returned elements will not be deleted from the collection , however sPop Will delete . These two commands can implement different lottery algorithms .

such as , There are 100 Elements , Value from number 1 To digital 100. We define what we draw as numbers 1 Words , It means winning the prize .

Use sRandMember Words , No matter how many times I smoked before , The probability of winning the next time is 1%. While using sPop Words , Then the probability of winning each time is different . The probability of the first person winning is 1%, When the first person doesn't win , The second person's probability of winning is 1/99, And so on .

The lottery function is realized

There are only two steps to realize the lottery function , First, set the lottery probability , That is, add elements to the set , Then the lottery begins .

Set the lottery probability , The pseudocode is as follows ：

 // sweepstakes , Get an exchange code   Definition 1-10 Win the prize 
    public function create($key = 'draw', $type = 'nil')
    {
        //tp6 load redis
        $redis = Cache::store('redis')->handler();
        // Winning logic 
        if ($type == 'nil') {
            //  The probability of ordinary users is small   Algorithm   No duplication   To generate exchange code 
            $num = mt_rand(7, 9999);
        } else if ($type == 'VIP') {
            $num = mt_rand(3, 1000);
        } else if ($type == 'VIP8') {
            $num = mt_rand(1, 2);
        }

        $redis->sAdd($key, $num);

        return $num;
    }

 // A prize   Lottery only   Don't write logic 
    public function read($key, $stand = 10)
    {
        $bool = $this->draw($key, $stand = 10);
        // Lottery results for users 
        return $bool ? ' Congratulations on winning the prize , The son of the chosen ' : ' unfortunately , Nearly 100 million points won the prize ';
    }

    // Write the lottery logic 
    public function draw($key, $stand)
    {
        $redis = Cache::store('redis')->handler();
        // Judge whether there is any lottery content in the collection 
        if ($redis->scard($key) > 0) {
            // Real random lottery 
            $number = $redis->spop($key);
        } else {
            echo " The draw is over ";
            exit();
        }

        echo $number . "<hr/>";
        return $number < $stand;
    }

Be careful ： Route parameters