HTML Parsing and Screen Scraping With the Simple HTML DOM Library

This tutorial demonstrates how to efficiently parse HTML using an open-source parser, avoiding the complexities of regular expressions. We'll scrape Envato Tuts as an example, extracting article titles and descriptions. This is for illustrative purposes; remember to always obtain permission before scraping a website.

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1. Setup

Begin by installing Composer, a PHP package manager, to simplify library installation.

Further steps are detailed below.

Documentation

Comprehensive documentation is available on the project's official GitHub repository.

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3. Practical Application: Scraping Envato Tuts

Let's create a script to extract article titles and descriptions from Envato Tuts . This is a demonstration and should not be performed without permission. Scraping can overload servers.

The core code snippet:

use voku\helper\HtmlDomParser;
require_once 'vendor/autoload.php';

$articles = [];
getArticles('https://code.tutsplus.com/tutorials');

This includes the necessary library and initializes an array to store article data. The getArticles function (defined later) fetches and processes the webpage.

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5. Data Extraction

The heart of the script extracts article information:

$items = $html->find('article');
foreach($items as $post) {
    $articles[] = [
        /* title */ $post->findOne(".posts__post-title")->firstChild()->text(),
        /* description */ $post->findOne("posts__post-teaser")->text()
    ];
}

This iterates through each article element (<article>) and extracts the title and description using CSS selectors. Each $articles entry will contain a title and description pair. For example:

$articles[0][0] = "My Article Name Here";
$articles[0][1] = "This is my article description";

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6. Handling Pagination

To handle multiple pages, we identify the "next" page link:

The relevant HTML:

<a aria-label="next" class="pagination__button pagination__next-button" href="https://www.php.cn/link/a3cdf7cabc49ea4612b126ae2a30ecbf" rel="next"><i class="fa fa-angle-right"></i></a>

The script finds this link, extracts the href attribute, and recursively calls getArticles() for subsequent pages. Crucially, the $html object is cleared to prevent memory exhaustion.

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Conclusion

Parsing large websites can be time-consuming. This tutorial provides a foundation for HTML parsing using a user-friendly library. While this library is convenient, remember that other methods, such as PHP's built-in DOM manipulation with XPath, exist. Always prioritize obtaining permission before scraping any website.

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