PHP uses Redis to add locks

1.redis Lock introduces this class

<?php/** * Redis lock Operation class * date:2016-06-30 * author:fdipzone * ver:1.0 * * FUNC: * Public lock get
    Lock * Public Unlock release lock * Private Connect * * class Redislock {//class start Private $_config;

    Public $_redis; /** * Initialization * @param Array $config Redis Connection Set/Public function __construct ($config =array ()) {$th
        Is->_config = $config;
    $this->_redis = $this->connect ();
     /** * Acquire lock * @param String $key Lock ID * @param Int $expire Lock expiration * @return Boolean

        * * Public Function Lock ($key, $expire =5) {$is _lock = $this->_redis->setnx ($key, Time () + $expire);

            Cannot get lock if (! $is _lock) {//To determine whether the lock expires $lock _time = $this->_redis->get ($key);
                The lock is expired, the lock is removed, and the If (Time () > $lock _time) {$this->unlock ($key) is retrieved;
$is _lock = $this->_redis->setnx ($key, Time () + $expire);            } return $is _lock?
    True:false;
        /** * Release lock * @param String $key Lock Identification * @return Boolean/Public Function unlock ($key) {
    return $this->_redis->del ($key); /** * Create redis Connection * @return Link/private Function connect () {try{$redis =
            New Redis (); $redis->connect ($this->_config[' host '), $this->_config[' Port ', $this->_config[' timeout '], $this->
            _config[' reserved '], $this->_config[' retry_interval ']);
            if (!empty ($this->_config[' auth ')) {$redis->auth ($this->_config[' auth '));
        $redis->select ($this->_config[' index '));
            }catch (Redisexception $e) {throw new Exception ($e->getmessage ());
        return false;
    return $redis;

 }//Class end

2. Call

        $oRedisLock = new Redislock ($config);

      Get the lock, try 3 for
        ($i =0 $i <=3; $i + +) {
            $is _lock = $oRedisLock->lock ($key, 2);
            if ($is _lock) {break
                ;
            }
        }

        if ($is _lock) {

            //dosth logic

            /release lock
            $is _lock = $oRedisLock->unlock ($key);
            
        } else{
        }

3. A simpler way

SET key value [EX seconds] [PX milliseconds] [nx| XX]

Starting with the version of Redis 2.6.12, the behavior of the SET command can be modified by a series of parameters: EX Second: The SET key expires in second seconds. The SET key value EX second effect is equivalent to Setex key second value. PX millisecond: Sets the key's expiration time to millisecond milliseconds. The SET key value PX millisecond effect is equivalent to Psetex key millisecond value. NX: The key is set to operate only if the key does not exist. The SET key value NX effect is equivalent to Setnx key value. XX: The key is set to operate only if the key already exists.

1, client A requests the server to set the value of the key, if the success of the set to indicate the success of the lock
    2, Client B also to request the server to set the value of the key, if the return failure, then on behalf of Lock failed
    3, client a executes code completion, delete the lock
    4, Client B waits for a while to request the value of the set key, set success
    5, Client B execute code completion, delete the lock

    $redis->set ($key, $value, Array (' NX ', ' ex ' => $ttl));  Ex represents seconds