May 26, 2018

Small, efficient web crawler with advanced features

The crawl utility starts a depth-first traversal of the web at the specified URLs. It stores all JPEG images that match the configured constraints. Crawl is fairly fast and allows for graceful termination. After terminating crawl, it is possible to restart it at exactly the same spot where it was terminated. Crawl keeps a persistent database that allows multiple crawls without revisiting sites.

The main reason for writing crawl was the lack of simple open source web crawlers. Crawl is only a few thousand lines of code and fairly easy to debug and customize.

Some of the main features

  • Saves encountered JPEG images
  • Image selection based on regular expressions and size contrainsts
  • Resume previous crawl after graceful termination
  • Persistent database of visited URLs
  • Very small and efficient code
  • Supports robots.txt

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