phpSpider practical tips: How to deal with anti-crawler strategies?

phpSpider practical skills: How to deal with anti-crawler strategies?

Introduction: With the development of the Internet, data collection from websites has become a common task. In order to protect its own data, websites have adopted various anti-crawler strategies accordingly. This article will introduce some practical skills of phpSpider to deal with anti-crawler strategies and give corresponding code examples.

1. Using delayed requests
   In order to detect crawlers, websites often check the request time interval. If the request is too frequent, further responses will be refused. At this point, we can circumvent this detection by adding a delay between each request.

// 添加延时函数，在每次请求之间暂停一定时间
function delayRequest($interval) {
    usleep($interval * 1000); // 暂停指定毫秒数
}

// 请求之前添加延时
delayRequest(500); // 暂停500毫秒
$request->get($url);

2. Random User-Agent
   The website can determine whether the request comes from a crawler by checking the User-Agent field. Using PHP's curl library, we can customize the User-Agent field and generate it randomly for each request.

$user_agents = array(
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3",
    "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3",
    // 可以添加更多的User-Agent
);

// 随机选择一个User-Agent
$user_agent = $user_agents[array_rand($user_agents)];

// 设置User-Agent字段
curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);

3. Use proxy IP
   In some anti-crawler strategies, websites will prohibit frequent requests from the same IP address. Using proxy IP, you can change the source IP of the request in turn to avoid the request being rejected.

$proxy_list = array(
    "http://10.10.1.10:3128",
    "http://192.168.0.1:8080",
    "http://proxy.example.com:8888",
    // 可以添加更多的代理IP
);

// 随机选择一个代理IP
$proxy = $proxy_list[array_rand($proxy_list)];

// 设置代理IP
curl_setopt($ch, CURLOPT_PROXY, $proxy);

4. Processing verification codes
   Some websites will set verification codes in order to prevent malicious requests from robots. In order to automate the processing of verification codes, we can use third-party libraries (such as the GD library) for image processing and recognition.

// 使用GD库生成验证码图片
$gd = imagecreate(200, 80);
$background_color = imagecolorallocate($gd, 255, 255, 255);
$text_color = imagecolorallocate($gd, 0, 0, 0);
imagestring($gd, 5, 20, 30, 'ABCD', $text_color);

// 保存验证码图片
imagejpeg($gd, 'captcha.jpg');

// 使用第三方库进行验证码识别
// ...

Conclusion:
The above are some phpSpider practical skills that can deal with common anti-crawler strategies. Of course, the website’s anti-crawler strategy is also constantly being upgraded, so we need to flexibly adjust our technical solutions. At the same time, we must also abide by crawler specifications, respect the privacy and data permissions of the website, and avoid malicious collection behaviors.

I hope this article will help you understand phpSpider’s anti-crawler strategies!

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