A Coding Implementation of Crawl4AI for Web Crawling, Markdown Generation, JavaScript Execution, and LLM-Based Structured Extraction

It looks like you're working through a comprehensive tutorial or guide on using the Crawl4AI library to extract and process data from web pages. Let's break down what each part of your code does:

Part 10: Deep Crawling

In this section, you are demonstrating how to perform deep crawling (i.e., traversing multiple levels of a website) starting from a seed URL using the Breadth-First Search (BFS) strategy.

Key Components:

• FilterChain: A chain of filters that can be applied to URLs during the crawl process. In your example, it includes DomainFilter and URLPatternFilter.

  • DomainFilter: Allows or blocks specific domains.
  • URLPatternFilter: Matches URL patterns against a list of allowed/blocked patterns.

• BFSDeepCrawlStrategy: A strategy for deep crawling that uses BFS to explore pages up to a certain depth or number of pages. It takes parameters like max_depth, max_pages, and the filter chain.

• AsyncWebCrawler: The main class used for performing asynchronous web crawls.

Example Code:

python
 
1from crawl4ai.deep_crawling import BFSDeepCrawl
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3[Read the full article at MarkTechPost](https://www.marktechpost.com/2026/04/14/a-coding-implementation-of-crawl4ai-for-web-crawling-markdown-generation-javascript-execution-and-llm-based-structured-extraction/)
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