README
TRAWL4-alpha: A low memory footprint web crawler with a MySQL backend
Overview
This is a CLI tool for recursively crawling websites.
It:
- discovers links and recursively follows them
- adds crawled pages (URL, content) to a MySQL database for further processing
Features:
- recursive, suitable for crawling/spidering an entire website/domain
- respects the robots.txt standard https://en.wikipedia.org/wiki/Robots_exclusion_standard
- holds an in-memory LRU for discovered links so the DB is not hit hard
- auto-restarts session to avoid memory leaks
- uses about 240MB RAM per typical crawl session
How do I get set up?
Clone this repository and follow these simple steps:
First, create an empty database (the crawler will create the tables automatically):
echo "CREATE DATABASE your_db_name" |mysql
Then modify lib/db/connect.js to suit your MySQL setup (user/password and database name)
Example: mysql://user:password@localhost/your_db_name
Now the obligatory
npm i
or
yarn
You're set!
Now run the crawler with:
npm run demo
You can hit Ctrl+C to stop crawling and wait about 2 seconds for the script to finish the exit routines.
Running npm run demo once more will resume the crawling.
The script will auto-restart itself every 100 URLs to work around a memory leak in cheerio
See lib/constants.js for more settings regarding crawl delay, in-memory LRU cache size, user agent and others
Be a good citizen
Please don't abuse the demo configuration, write your own (for example ./config/my_config.js) in and run it with
node runner.js --preset my_config