Warcbase

Warcbase is an open-source platform for managing web archives built on HBase. The platform provides a flexible data model for storing and managing raw content as well as metadata and extracted knowledge. Tight integration with Hadoop provides powerful tools for analytics and data processing.

Getting Started

Once you check out the repo, build WarcBase:

mvn clean package appassembler:assemble

Ingesting Content

Ingesting archive content from ARC or WARC files:

$ setenv CLASSPATH_PREFIX "/etc/hbase/conf/"
$ sh target/appassembler/bin/IngestWarcFiles -dir /path/to/warc/ -name archive_name -create

Command-line options:

• Use the -dir option to specify directory containing WARC files.
• Use the -name option to specify the name of the archive (will correspond to the HBase table name).
• Use the -create option to create a new table (and drop the existing table if a table with the same name exists already). Alternatively, use -append to add to an existing table.

Starting the browser:

$ setenv CLASSPATH_PREFIX "/etc/hbase/conf/"
$ sh target/appassembler/bin/WarcBrowser -port 9191 -server http://myhost:9191/

Navigate to http://myhost:9191/ to browse the archive.

Extracting the Webgraph

First, use a MapReduce tool to extract all URLs from ARC data:

$ hadoop jar target/warcbase-0.1.0-SNAPSHOT-fatjar.jar \
  org.warcbase.analysis.demo.MapReduceArcDemo \
  -input inputDir -output outputDir

Next, build an FST for the URLs (using Lucene's FST package). The two relevant classes in Warcbase are:

• UriMappingBuilder: takes a list of URLs as input and builds the FST mapping.
• UriMapping: load the mapping file generated by Builder and provides an API for accessing the FST.

To build the Lucene FST :

$ sh target/appassembler/bin/UriMappingBuilder inputDirectory outputFile

This command will read all files under inputDirectory as input, build an FST, and write the data file to outputFile. The UriMapping class provides a simple command-line interface:

# Lookup by URL, fetches the integer id
$ sh target/appassembler/bin/UriMapping -data fst.dat -getId http://www.foo.com/

# Lookup by id, fetches the URL
$ sh target/appassembler/bin/UriMapping -data fst.dat -getUrl 42

# Fetches all URLs with the prefix
$ sh target/appassembler/bin/UriMapping -data fst.dat -getPrefix http://www.foo.com/

Then, we can use the FST mapping data to extract the webgraph and at the same time map URLs to unique integer ids. This is accomplished by a Hadoop program:

$ hadoop jar target/warcbase-0.1.0-SNAPSHOT-fatjar.jar org.warcbase.data.ExtractLinks 
  -input inputDir -output outputDir -uriMapping fstData -numReducers 1

Finally, instead of extracting links between individual URLs, we can extract the site-level webgraph by merging all URLs with common prefix into a "supernode". Link counts between supernodes represent the total number of links between their sub-URLs. In order to do this, following input files are required:

• a prefix file providing URL prefixes for each supernode (comma-delimited: id, URL prefix);
• an FST mapping file to map individual URLs to unique integer ids (from above);
• a directory containing the original link graph (which can be extracted from the previous step).

Then run this program:

$ sh target/appassembler/bin/ExtractSiteLinks -prefixfile prefix.data 
  -fstfile fst.data -linkdir extract-links-data  -output sitelinks.data