MatthiasMullie\Scrapbook\Adapters\Redis::set PHP Method

    public function set($key, $value, $expire = 0)
    {
        $ttl = $this->ttl($expire);
        /*
         * Negative ttl behavior isn't properly documented & doesn't always
         * appear to treat the value as non-existing. Let's play safe and just
         * delete it right away!
         */
        if ($ttl < 0) {
            $this->delete($key);
            return true;
        }
        /*
         * phpredis advises: "Calling setex() is preferred if you want a Time To
         * Live". It seems that setex it what set will fall back to if you pass
         * it a TTL anyway.
         * Redis advises: "Note: Since the SET command options can replace
         * SETNX, SETEX, PSETEX, it is possible that in future versions of Redis
         * these three commands will be deprecated and finally removed."
         * I'll just go with set() - it works and seems the desired path for the
         * future.
         *
         * @see https://github.com/ukko/phpredis-phpdoc/blob/master/src/Redis.php#L190
         * @see https://github.com/phpredis/phpredis#set
         * @see http://redis.io/commands/SET
         */
        return $this->client->set($key, $value, $ttl);
    }

 /**
  * Shared between increment/decrement: both have mostly the same logic
  * (decrement just increments a negative value), but need their validation
  * & use of non-ttl native methods split up.
  *
  * @param string $key
  * @param int    $offset
  * @param int    $initial
  * @param int    $expire
  *
  * @return int|bool
  */
 protected function doIncrement($key, $offset, $initial, $expire)
 {
     $ttl = $this->ttl($expire);
     $this->client->watch($key);
     $value = $this->client->get($key);
     if ($value === false) {
         /*
          * Negative ttl behavior isn't properly documented & doesn't always
          * appear to treat the value as non-existing. Let's play safe and not
          * even create the value (also saving a request)
          */
         if ($ttl < 0) {
             return true;
         }
         // value is not yet set, store initial value!
         $this->client->multi();
         $this->client->set($key, $initial, $ttl);
         /** @var bool[] $return */
         $return = (array) $this->client->exec();
         return !in_array(false, $return) ? $initial : false;
     }
     // can't increment if a non-numeric value is set
     if (!is_numeric($value) || $value < 0) {
         /*
          * HHVM Redis only got unwatch recently.
          * @see https://github.com/asgrim/hhvm/commit/bf5a259cece5df8a7617133c85043608d1ad5316
          */
         if (method_exists($this->client, 'unwatch')) {
             $this->client->unwatch();
         } else {
             // this should also kill the watch...
             $this->client->multi()->discard();
         }
         return false;
     }
     $value += $offset;
     // value can never be lower than 0
     $value = max(0, $value);
     $this->client->multi();
     /*
      * Negative ttl behavior isn't properly documented & doesn't always
      * appear to treat the value as non-existing. Let's play safe and just
      * delete it right away!
      */
     if ($ttl < 0) {
         $this->client->del($key);
     } else {
         $this->client->set($key, $value, $ttl);
     }
     /** @var bool[] $return */
     $return = (array) $this->client->exec();
     return !in_array(false, $return) ? $value : false;
 }