Heritrix

Infobox_Software
name = Heritrix


caption = Screenshot of Heritrix Admin Console.
developer =
latest_release_version = 2.0.1
latest_release_date = release date|2008|08|07
operating_system = Linux/Unix-like/Windows(unsupported)
programming_language = Java
genre = Web crawler
license = GNU Lesser General Public License
website = http://crawler.archive.org

Heritrix is the Internet Archive’s web crawler which was specially designed for web archiving. It is open-source and written in Java. The main interface is accessible using a web browser, and there is a command-line tool that can optionally be used to initiate crawls.

Heritrix was developed jointly by Internet Archive and the Nordic national libraries on specifications written in early 2003. The first official release was in January 2004, and it has been continually improved by members of the Internet Archive and other interested third parties.

Projects using Heritrix

A number of organizations and national libraries are using Heritrix:
* [http://www.cbi.umn.edu/documentinginternet2/ Documenting Internet2]
* Library and Archives Canada
* National and University Library of Iceland
* National Library of New Zealand
* [http://netarkivet.dk/ Netarkivet.dk]

Arc files

Heritrix by default stores the web resources it crawls in an Arc file. The [http://www.archive.org/web/researcher/ArcFileFormat.php Arc file format] has been used by the Internet Archive since 1996 to store their web archives. Heritrix can also be configured to store files in a directory format similar to the Wget crawler that uses the URL to name the directory and filename of each resource.

An Arc file stores multiple archived resources in a single file in order to avoid managing a large number of small files. The file consists of a sequence of URL records, each with a header containing metadata about how the resource was requested followed by the HTTP header and the response. Arc files range between 100 to 600 MB.

Example:

filedesc://IA-2006062.arc 0.0.0.0 20060622190110 text/plain 76 1 1 InternetArchive URL IP-address Archive-date Content-type Archive-length http://foo.edu:80/hello.html 127.10.100.2 19961104142103 text/html 187 HTTP/1.1 200 OK Date: Thu, 22 Jun 2006 19:01:15 GMT Server: Apache Last-Modified: Sat, 10 Jun 2006 22:33:11 GMT Content-Length: 30 Content-Type: text/html Hello World!!!

Tools for processing Arc files

Heritrix includes a command-line tool called arcreader which can be used to extract the contents of an Arc file. The following command lists all the URLs and metadata stored in the given Arc file (in [http://www.archive.org/web/researcher/cdx_legend.php CDX] format):

arcreader IA-2006062.arc

The following command extracts hello.html from the above example assuming the record starts at offset 140:

arcreader -o 140 -f dump IA-2006062.arc

Other tools:
* [http://wiki.lib.umn.edu/DI2/HowToCrawl Arc processing tools]
* [http://archive-access.sourceforge.net/projects/wera/ WERA (Web ARchive Access)]

Command-line tools

Heritrix comes with several command-line tools:

* htmlextractor - displays the links Heritrix would extract for a given URL
* hoppath.pl - recreates the hop path (path of links) to the specified URL from a completed crawl
* manifest_bundle.pl - bundles up all resources referenced by a crawl manifest file into an uncompressed or compressed tar ball
* cmdline-jmxclient - enables command-line control of Heritrix
* arcreader - extracts contents of ARC files (see above)

See also

* Internet Archive
* National Digital Information Infrastructure and Preservation Program
* Web crawler

References

*
*
*

External links

Tools by Internet Archive:

* [http://crawler.archive.org/ Heritrix - official website]
* [http://archive-access.sourceforge.net/projects/nutch/ NutchWAX] - search web archive collections
* [http://archive-access.sourceforge.net/projects/wayback/ Wayback (Open source Wayback Machine)] - search and navigate web archive collections using NutchWax

Links to related tools:

* [http://www.archive.org/web/researcher/ArcFileFormat.php Arc file format]
* [http://crawler.archive.org/faq.html#windows How to run Heritrix in Windows]
* [http://archive-access.sourceforge.net/projects/wera/ WERA (Web ARchive Access)] - search and navigate web archive collections using NutchWAX