phpSpider practical tips: How to deal with dynamic loading of web content?

phpSpider Practical Tips: How to deal with dynamic loading of web content?

When crawling web page data, we often encounter the problem that dynamically loaded content cannot be obtained directly through the crawler. These dynamically loaded contents can be data obtained through AJAX requests, DOM elements rendered through JavaScript, etc. In order to solve this problem, this article will introduce some practical tips for dealing with dynamic loading problems of web pages when using phpSpider.

1. Use network debugging tools to find dynamically loaded URLs

Before processing dynamically loaded content, you first need to find the URL of loaded content. This can be accomplished by using your browser's developer tools or network debugging tools. Generally speaking, the URL for loading content will be sent to the server in the form of an AJAX request or other network request. By analyzing network requests, we can obtain the URL of the dynamically loaded content for subsequent processing.

The following is a sample code that uses phpSpider to crawl dynamically loaded content:

<?php

use phpspidercoreequests;
use phpspidercoreselector;

require_once 'your_phpspider_autoload.php';

$target_url = "https://www.example.com";
$response = requests::get($target_url);

$html = selector::select($response, "//body");

// 通过网络调试工具获取动态加载的URL
$ajax_url = "https://www.example.com/ajax/get_data";

$params = [
    'param1' => 'value1',
    'param2' => 'value2'
];

$response = requests::post($ajax_url, $params);

$dynamic_content = json_decode($response, true)['result'];

// 处理动态加载的内容
// TODO: 对动态加载的内容进行处理

// 继续处理原始网页内容
// TODO: 对原始网页内容进行处理

?>

In the above sample code, we sent a POST request to the URL of dynamically loaded content through the requests class, And save the returned content in the $dynamic_content variable. Next, we can process the content in the $dynamic_content variable.

2. Use JavaScript to parse dynamically loaded content

For DOM elements rendered through JavaScript, we can use PHP-based headless browser libraries such as php-webdriver to achieve it. The php-webdriver library can simulate browser behavior, allowing us to execute JavaScript code like a browser to obtain rendered DOM elements.

The following is a sample code that uses the php-webdriver library to parse dynamically loaded content:

<?php

require_once 'your_phpspider_autoload.php';

use FacebookWebDriverRemoteDesiredCapabilities;
use FacebookWebDriverRemoteRemoteWebDriver;
use FacebookWebDriverWebDriverBy;
use FacebookWebDriverWebDriverExpectedCondition;

$target_url = "https://www.example.com";

$host = 'http://localhost:4444/wd/hub';  
$driver = RemoteWebDriver::create($host, DesiredCapabilities::chrome());
$driver->get($target_url);

// 等待页面加载完成
$driver->wait()->until(
    WebDriverExpectedCondition::visibilityOfElementLocated(
        WebDriverBy::cssSelector('body')
    )
);

$html = $driver->getPageSource();

// 通过解析渲染后的DOM元素获取动态加载的内容
$dynamic_content = $driver->findElement(WebDriverBy::id('dynamic_content'))->getAttribute('innerHTML');

// 处理动态加载的内容
// TODO: 对动态加载的内容进行处理

// 继续处理原始网页内容
// TODO: 对原始网页内容进行处理

// 关闭浏览器
$driver->quit();

?>

In the above sample code, we use the php-webdriver library to create a chrome browser instance, and The target URL was visited. By calling the findElement method and getAttribute method, we can obtain dynamically loaded content. Next, we can process the content in the $dynamic_content variable.

Summary:

Dealing with the dynamic loading of web content is a common and important task for crawler development. This problem can be solved well by using network debugging tools to find dynamically loaded URLs and using phpSpider related libraries to obtain dynamically loaded content or by simulating browser behavior to obtain rendered DOM elements. We hope that the practical tips introduced in this article can help readers better deal with the dynamic loading of web content.

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