How to Build a Basic Web Crawler in PHP?

Crawling with PHP

In today's digital landscape, the ability to retrieve and store data from multiple web pages is a valuable asset. This article delves into creating a basic web crawler in PHP, providing you with the necessary steps to extract data from specified links and save it in a local file.

To initiate the crawling process, you'll start by defining the initial URL and the maximum depth of links to follow. The "crawl_page" function serves as the core of the crawler, utilizing the DOMDocument class to parse the HTML content of a given page.

Within the parsed document, you'll extract all links represented by the tag. Each link's "href" attribute is modified to ensure proper linking, taking into account relative paths and any modifications to the URL.

Note: It's important to avoid using regular expressions when dealing with HTML content. Instead, the DOM provides a robust framework for parsing and accessing HTML elements.

The function recursively crawls the retrieved links, following the provided depth parameter. Finally, the content of each crawled page is echoed to standard output, allowing you to redirect it to a file of your choice.

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