Nutch Selenium

This plugin allows you to fetch javascript pages using Selenium, while relying on the rest of the awesome Nutch stack! This allows you to

A) Leverage Nutch, a world class web crawler

B) Not have to use some paid service just to perform large-scale javascript/ajax aware web crawls

C) Not have to wait another 2 years for Nutch to patch in either the Ajax crawler hashbang workaround and then, not having to patch it to get the use case of ammending the original url with the hashbang-workaround's content.

The underlying code is based on the nutch-htmlunit plugin, which was in turn based on nutch-httpclient. I also have patches to send through on nutch-htmlunit which get it working with nutch 2.2.1, so stay tuned if you want to use htmlunit for some reason.

IMPORTANT NOTES:

1. This plugin is currently being merged into the Nutch Core - see issue #1933 on Nutch's JIRA

2. A version of this plugin which relies on the Selenium Hub/Node system can be found here: https://github.com/momer/nutch-selenium-grid-plugin

Installation (tested on Ubuntu 14.0x)

Part 1: Setting up Selenium

A) Ensure that you have Firefox installed

# More info about the package @ [launchpad](https://launchpad.net/ubuntu/trusty/+source/firefox)

sudo apt-get install firefox

B) Install Xvfb and its associates

sudo apt-get install xorg synaptic xvfb gtk2-engines-pixbuf xfonts-cyrillic xfonts-100dpi \
    xfonts-75dpi xfonts-base xfonts-scalable freeglut3-dev dbus-x11 openbox x11-xserver-utils \
    libxrender1 cabextract

C) Set a display for Xvfb, so that firefox believes a display is connected

sudo /usr/bin/Xvfb :11 -screen 0 1024x768x24 &
sudo export DISPLAY=:11

Part 2: Installing plugin for Nutch (where NUTCH_HOME is the root of your nutch install)

A) Add Selenium to your Nutch dependencies

<!-- NUTCH_HOME/ivy/ivy.xml -->

<ivy-module version="1.0">
  <dependencies>
    ...
    <!-- begin selenium dependencies -->
    <dependency org="org.seleniumhq.selenium" name="selenium-java" rev="2.42.2" />

    <dependency org="com.opera" name="operadriver" rev="1.5">
      <exclude org="org.seleniumhq.selenium" name="selenium-remote-driver" />
    </dependency>
    <!-- end selenium dependencies -->
  </dependencies>
</ivy-module>

B) Add the required plugins to your NUTCH_HOME/src/plugin/build.xml

<!-- NUTCH_HOME/src/plugin/build.xml -->

<project name="Nutch" default="deploy-core" basedir=".">
  <!-- ====================================================== -->
  <!-- Build & deploy all the plugin jars.                    -->
  <!-- ====================================================== -->
  <target name="deploy">
    ... 
    <ant dir="lib-selenium" target="deploy"/>
    <ant dir="protocol-selenium" target="deploy" />
  </target>
      ...
</project>

C) Ensure that the plugin will be used as the fetcher/initial parser in your config

<!-- NUTCH_HOME/conf/nutch-site.xml -->

<configuration>
  ...
  <property>
    <name>plugin.includes</name>
    <value>protocol-selenium|urlfilter-regex|parse-(html|tika)|index-(basic|anchor)|urlnormalizer-(pass|regex|basic)|scoring-opic</value>
    <description>Regular expression naming plugin directory names to
    include.  Any plugin not matching this expression is excluded.
    In any case you need at least include the nutch-extensionpoints plugin. By
    default Nutch includes crawling just HTML and plain text via HTTP,
    and basic indexing and search plugins. In order to use HTTPS please enable 
    protocol-httpclient, but be aware of possible intermittent problems with the 
    underlying commons-httpclient library.
    </description>
  </property>

D) Add the plugin folders to your installation's NUTCH_HOME/src/plugin directory

E) Compile nutch

ant runtime

F) Start your web crawl (Ensure that you followed the above steps and have started your xvfb display as shown above)

NUTCH_HOME/runtime/local/bin/crawl /opt/apache-nutch-2.2.1/urls/ webpage $NUTCH_SOLR_SERVER $NUTCH_CRAWL_DEPTH