cdx-toolkit 0.9.3

A toolkit for working with CDX indices

cdx_toolkit is a set of tools for working with CDX indices of web crawls and archives, including those at CommonCrawl and the Internet Archive’s Wayback Machine.

CommonCrawl uses Ilya Kramer’s pywb to serve the CDX API, which is somewhat different from the Internet Archive’s CDX API. cdx_toolkit hides these differences as best it can. cdx_toolkit also knits together the monthly Common Crawl CDX indices into a single, virtual index.

• https://github.com/webrecorder/pywb/wiki/CDX-Server-API

• https://github.com/internetarchive/wayback/tree/master/wayback-cdx-server

Installing

$ pip install cdx_toolkit

or clone this repo and use python setup.py install.

Example

import cdx_toolkit

cdx = cdx_toolkit.CDXFetcher(source='cc', cc_duration='90d')
url = 'commoncrawl.org/*'

print(url, 'size estimate', cdx.get_size_estimate(url))

for obj in cdx.items(url, limit=10):
    print(obj)

at the moment will print:

size estimate 6000
http://commoncrawl.org/ 200
http://commoncrawl.org/ 200
http://commoncrawl.org/ 200
http://www.commoncrawl.org/ 301
https://www.commoncrawl.org/ 301
http://www.commoncrawl.org/ 301
http://commoncrawl.org/ 200
http://commoncrawl.org/2011/12/mapreduce-for-the-masses/ 200
http://commoncrawl.org/2012/03/data-2-0-summit/ 200
http://commoncrawl.org/2012/03/twelve-steps-to-running-your-ruby-code-across-five-billion-web-pages/ 200

Command-line tools

The above example can also be done as

$ cdx_size 'commoncrawl.org/*' --cc
$ cdx_iter 'commoncrawl.org/*' --cc --limit 10 --cc-duration='90d'

or

$ cdx_size 'commoncrawl.org/*' --ia
$ cdx_iter 'commoncrawl.org/*' --ia --limit 10

cdx_iter can generate jsonl or csv outputs; see

$ cdx_iter --help

for details.

CDX Jargon, Field Names, and such

A capture is a single crawled url, be it a copy of a webpage, a redirect to another page, an error such as 404 (page not found), or a revisit record (page identical to a previous capture.)

The url used by cdx_tools can be wildcarded in two ways. One way is *.example.com, which in CDX jargon sets matchType=’domain’, and will return captures for blog.example.com, support.example.com, etc. The other, example.com/*, will return captures for any page on example.com.

A timestmap represents year-month-day-time as a string of digits run togther. Example: January 5, 2016 at 12:34:56 UTC is 20160105123456. These timestamps are a field in the index, and are also used to pick specify the dates used by –from=, –to, and –closest on the command-line. (Programmatically, use from_ts=, to=, and closest=.)

An urlkey is a SURT, which is a munged-up url suitable for deduplication and sorting. This sort order is how CDX indices efficiently support queries like *.example.com. The SURTs for www.example.com and example.com are identical, which is handy when these 2 hosts actually have identical web content. The original url should be present in all records, if you want to know exactly what it is.

CDX Indices support a paged interface for efficient access to large sets of URLs. cdx_toolkit uses this interface under the hood. cdx_toolkit is also polite to CDX servers by being single-threaded and serial. If it’s not fast enough for you, consider downloading Common Crawl’s index files directly.

A digest is a sha1 checksum of the contents of a capture. The purpose of a digest is to be able to easily figure out if 2 captures have identical content.

Common Crawl publishes a new index each month. cdx_toolkit will automatically start using new ones as published. The –cc-duration command-line flag (and cc_duration= constructor argument) specifies how many days back to look. The default is ‘365d’, 365 days.

CDX implementations do not efficiently support reversed sort orders, so cdx_toolkit results will be ordered by ascending SURT and by ascending timestamp. However, since CC has an individual index for each month, and because most users want more recent results, cdx_toolkit defaults to querying CC’s CDX indices in decreasing month order, but each month’s result will be in ascending SURT and ascending timestamp. If you’d like pure ascending, set –cc-sort or cc_sort= to ‘ascending’. You may want to also specify –from or from_ts= to set a starting timestamp.

The main problem with this ascending sort order is that it’s a pain to get the most recent N captures: –limit and limit= will return the oldest N captures.

TODO

Add a call to download a capture from ia or cc, given an URL and a timestamp.

Status

cdx_toolkit has reached the “I hacked this together out of some other code for a hackathon this weekend” stage of development.

License

Apache 2.0