A brief discussion on the chain of responsibility model in PHP

abstract class Handler
{
    protected $successor;
    public function setSuccessor($successor)
    {
        $this->successor = $successor;
    }
    abstract public function HandleRequst($request);
}

class ConcreteHandler1 extends Handler
{
    public function HandleRequst($request)
    {
        if (is_numeric($request)) {
            return '请求参数是数字：' . $request;
        } else {
            return $this->successor->HandleRequst($request);
        }
    }
}

class ConcreteHandler2 extends Handler
{
    public function HandleRequst($request)
    {
        if (is_string($request)) {
            return '请求参数是字符串：' . $request;
        } else {
            return $this->successor->HandleRequst($request);
        }
    }
}

class ConcreteHandler3 extends Handler
{
    public function HandleRequst($request)
    {
        return '我也不知道请求参数是啥了，你猜猜？' . gettype($request);
    }
}

$handle1 = new ConcreteHandler1();
$handle2 = new ConcreteHandler2();
$handle3 = new ConcreteHandler3();

$handle1->setSuccessor($handle2);
$handle2->setSuccessor($handle3);

$requests = [22, 'aaa', 55, 'cc', [1, 2, 3], null, new stdClass];

foreach ($requests as $request) {
    echo $handle1->HandleRequst($request) . PHP_EOL;
}

// 词汇过滤链条
abstract class FilterChain
{
    protected $next;
    public function setNext($next)
    {
        $this->next = $next;
    }
    abstract public function filter($message);
}

// 严禁词汇
class FilterStrict extends FilterChain
{
    public function filter($message)
    {
        foreach (['枪X', '弹X', '毒X'] as $v) {
            if (strpos($message, $v) !== false) {
                throw new \Exception('该信息包含敏感词汇！');
            }
        }
        if ($this->next) {
            return $this->next->filter($message);
        } else {
            return $message;
        }
    }
}

// 警告词汇
class FilterWarning extends FilterChain
{
    public function filter($message)
    {
        $message = str_replace(['打架', '丰胸', '偷税'], '*', $message);
        if ($this->next) {
            return $this->next->filter($message);
        } else {
            return $message;
        }
    }
}

// 手机号加星
class FilterMobile extends FilterChain
{
    public function filter($message)
    {
        $message = preg_replace("/(1[3|5|7|8]\d)\d{4}(\d{4})/i", "$1****$2", $message);
        if ($this->next) {
            return $this->next->filter($message);
        } else {
            return $message;
        }
    }
}

$f1 = new FilterStrict();
$f2 = new FilterWarning();
$f3 = new FilterMobile();

$f1->setNext($f2);
$f2->setNext($f3);

$m1 = "现在开始测试链条1：语句中不包含敏感词，需要替换掉打架这种词，然后给手机号加上星：13333333333，这样的数据才可以对外展示哦";
echo $f1->filter($m1);
echo PHP_EOL;

$m2 = "现在开始测试链条2：这条语句走不到后面，因为包含了毒X，直接就报错了！！！语句中不包含敏感词，需要替换掉打架这种词，然后给手机号加上星：13333333333，这样的数据才可以对外展示哦";
echo $f1->filter($m2);
echo PHP_EOL;