A very simple crawler

This tool can crawl a bunch of URLs for HTML content, and save the results in a nice WARC file. It has little control over its traffic, save for a limit on concurrent outbound requests. An external tool like trickle can be used to limit bandwidth.

Its main purpose is to quickly and efficiently save websites for archival purposes.

The crawl tool saves its state in a database, so it can be safely interrupted and restarted without issues.

Installation

Assuming you have a proper Go environment setup, you can install this package by running:

$ go install git.autistici.org/ale/crawl/cmd/crawl

This should install the crawl binary in your $GOPATH/bin directory.

Usage

Just run crawl by passing the URLs of the websites you want to crawl as arguments on the command line:

$ crawl http://example.com/

By default, the tool will store the output WARC file and its own database in the current directory. This can be controlled with the --output and --state command-line options.

The crawling scope is controlled with a set of overlapping checks:

• URL scheme must be one of http or https
• URL must have one of the seeds as a prefix (an eventual www. prefix is implicitly ignored)
• maximum crawling depth can be controlled with the --depth option
• resources related to a page (CSS, JS, etc) will always be fetched, even if on external domains, unless the --exclude-related option is specified

If the program is interrupted, running it again with the same command line from the same directory will cause it to resume crawling from where it stopped. At the end of a successful crawl, the database will be removed (unless you specify the --keep option, for debugging purposes).