Build an efficient web crawler using PHP and Selenium

With the advent of the information age, websites are considered to be one of the main ways to obtain information. However, it is very tedious to manually obtain information on the website, so there is a way to automatically crawl web pages - web crawlers. This article will introduce how to use PHP and Selenium to build an efficient web crawler to automatically collect information.

First, you need to install PHP and Selenium. Selenium is a web automation testing tool that simulates user operations on web pages. Selenium can interact with multiple languages, including PHP. For installation methods, please refer to the official documentation.

The next step is to integrate Selenium in PHP. First, install the Selenium library for PHP. It can be installed through Composer:

composer require facebook/webdriver

After installation, you need to define your web driver. The Chrome browser is used here, but Selenium supports multiple browsers. The following code can be saved as a separate file:

use FacebookWebDriverRemoteDesiredCapabilities;
use FacebookWebDriverRemoteRemoteWebDriver;

require_once('vendor/autoload.php');

$host = 'http://localhost:4444/wd/hub';

$capabilities = DesiredCapabilities::chrome();
$capabilities->setCapability('goog:chromeOptions', ['args' => ['--headless']]);

$driver = RemoteWebDriver::create($host, $capabilities);

Code analysis:

• Introducing the necessary classes and files
• defines the address and address of the driver Chrome browser options
• Create a connection to the driver through the RemoteWebDriver class

Once connected to the driver, you can start simulating user actions. For example, visit a website:

$driver->get('http://news.baidu.com');

This will open Baidu News and get all news links:

$news_links = $driver->findElements(WebDriverBy::cssSelector('.c-title a'));
$links = [];
foreach ($news_links as $news_link) {
    $links[] = $news_link->getAttribute('href');
}

Code analysis:

• Use WebDriverBy: :cssSelectorGet all news links through CSS selector method
• Traverse each link and get the URL of each link

Now you get all the news links, You can traverse them and crawl the content of each link in turn:

foreach ($links as $link) {
    $driver->get($link);
    $news_title = $driver->findElement(WebDriverBy::cssSelector('.article-title'))->getText();
    $news_content = $driver->findElement(WebDriverBy::cssSelector('.article-content'))->getText();
    // 保存新闻标题和内容至数据库
}

Code analysis:

• Locate the specified element through WebDriverBy::cssSelector, and Get the text content of the element
• Store the news title and content in the database

The above is the basis for building an efficient web crawler using PHP and Selenium. Of course, if you need further optimization, you can use it in combination with multiple tools and technologies, such as using multi-threading to improve efficiency, using font anti-obfuscation to solve the problem of some websites de-obfuscating fonts, etc. The world of crawlers is full of strange things, I hope you can Discover the methods and tools that work best for you!

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