PyCon DE & PyData 2025

Scraping LEGO for Fun: A Hacky Dive into Dynamic Data Extraction
2025-04-24 , Helium3

Unlock the full potential of modern web scraping by combining Python, Scrapy, and Playwright to extract data from dynamic, JavaScript-heavy sites—exemplified by LEGO product pages. This talk introduces Model Context Protocol (MCP) servers for orchestrating advanced data fetching, refining CSS selectors, and integrating Large Language Models for automated code suggestions. Learn how to scale ethically, handle concurrency, and respect site policies, while maintaining flexible, maintainable pipelines for diverse use cases from research to robotics.


Advanced Web Scraping: From LEGO to Production

Today's web landscape is teeming with JavaScript-heavy content, complex layouts, and sometimes opaque data structures. But what if you could reliably scrape rich product information—images, specs, descriptions—from modern e-commerce sites without hitting constant roadblocks? This session tackles advanced scraping with Python, Scrapy, and Playwright, exemplified by data extraction from LEGO product pages. We'll explore a "grey hat" perspective—applying a slightly "hacky" mindset—while stressing practical ethics, performance considerations, and compliance with site policies.

Outline

1. Introduction: The Hacky Spirit vs. Ethical Constraints

  • Why scrape LEGO?
  • Setting boundaries: terms of service, rate limiting, and disclaimers
  • When "scraping for fun" crosses into potential legal pitfalls

2. Scraping Tech Stack Overview

  • Scrapy for structured crawling and item pipelines
  • Playwright for rendering JavaScript and handling dynamic elements
  • Comparison to traditional HTML-only approaches
  • Project structure, environment setup, and practical tips

3. Spiders in Action

  • Product Spider: Extracting core product data (ID, name, specifications, multiple images)
  • Gallery Spider: Navigating hidden galleries, handling tricky JS-based carousels, and filtering unwanted images
  • Ensuring consistent output (JSON or database ingestion)

4. Model Context Protocol (MCP) Integration

  • Definition: Leveraging specialized helper servers for orchestrating data fetching, refining selectors, and automating debugging
  • Chaining Large Language Models: Code suggestions, auto-generation of selectors, and reactive error handling
  • Example workflow: "Broken selector? Ask the MCP server for an LLM-aided fix"

5. Performance & Scale

  • Polite but robust concurrency: balancing speed and TOS compliance
  • Handling large link lists, incremental updates, and site changes
  • Monitoring and logging for reliability, debugging, and optimization

6. Ethics & Privacy

  • Respecting site ownership, disclaimers, and usage limits
  • Storing scraped data securely and avoiding personal information
  • A discussion of "grey hat" territory: testing site vulnerabilities without exploiting them

7. Use Cases & Extensions

  • Research software engineering: building reproducible data sets
  • Robotics and embedded: offline or partial data ingestion for classification or motion planning
  • Future directions: advanced concurrency, containerization, and HPC

8. Demo & Q&A

  • Live snippet showing an MCP-powered spider reacting to a changed DOM structure
  • Q&A session on bridging the gap between hackery and best practices

Key Takeaways

  • Techniques for scraping dynamic, JS-heavy sites using Python, Scrapy, and Playwright
  • Practical "hacky" methods balanced by responsible, 'ethical approaches'
  • Introduction to Model Context Protocol servers for automated code refinement
  • Scalable patterns for data handling, from small tests to large-scale deployments

Whether you're a data engineer, hobbyist, or researcher, this talk provides a robust (and slightly subversive) recipe for capturing essential data from the wild world of modern websites—without crossing into unethical or unlawful territory.


Expected audience expertise: Domain:

Intermediate

Expected audience expertise: Python:

Intermediate

Public link to supporting material, e.g. videos, Github, etc.:

https://blog.pocok.dev/articles/lego-scraping

Hacker-maker, specialising in system infiltration and enhancement. Expert in reverse engineering, distributed systems architecture, and AI integration. Proven track record in high-stakes technical operations and system security.