1.
Web Scraping Using Nutch and Solr
● A simple example of using open source code
● Web Scrape a single web site - ours
● Environment and code
– Using Centos V6.2 ( Linux )
– Apache Nutch 1.6
– Solr 4.2.1
– Java 1.6

2.
Nutch and Solr Architecture
● Nutch processes urls and feeds content to Solr
● Solr indexes content

3.
Where to get source code
● Nutch
– http://nutch.apache.org
● Solr
– http://lucene.apache.org/solr
● Java
– http://java.com

4.
Installing Source - Nutch
● Nutch is delivered as
– apache-nutch-1.6-bin.tar ( 64M )
– apache-nutch-1.6-src.tar ( 20M )
● Copy each tar file to your desired location
● Install each tar file as
– tar xvf <tar file>
● Second tar file optional

5.
Installing Source - Solr
● Solr is delivered as
– solr-4.2.1.zip ( 116M )
● Copy file to your desired location
● Install each tar file as
– unzip <zip file>

6.
Configuring Nutch Part 1
● Assuming we will crawl a single web site
● Ensure that JAVA_HOME is set
● cd apache-nutch-1.6
● Edit agent name in conf/nutch-site.xml
<property>
<name>http.agent.name</name>
<value>Nutch Spider</value>
</property>
● mkdir -p urls ; cd urls ; touch seed.txt

7.
Configuring Nutch Part 2
● Add following url ( ours ) to seed.txt
– http://www.semtech-solutions.co.nz
● Change url filtering in conf/regex-urlfilter.txt, change the line
– # accept anything else
– +.
– To be
– +^http://([a-z0-9]*.)*semtech-solutions.co.nz/
● This means that we will filter the urls found to only be from the
local site

8.
Configuring Solr Part 1
● cd solr-4.2.1/example/solr/collection1/conf
● Add some extra fields to schema.xml after _version_ field i.e.

9.
Start Solr Server – Part 1
● Within solr-4.2.1/example
● Run the following command
● java -jar start.jar
● Now try to access admin web page for solr
– http://localhost:8983/solr/admin
● You should now see the admin web site
– ( see next page )

10.
Start Solr Server – Part 2
● Solr Admin web page

11.
Run Nutch / Solr
● We are ready to crawl our first web site
● Go to apache-nutch-1.6 directory
● Run the following commands
– touch nutch_start.bash
– chmod 755 nutch_start.bash
– vi nutch_start.bash
● Add the text to the file
#!/bin/bash
bin/nutch crawl urls -solr http://localhost:8983/solr/
-dir crawl -depth 3 -topN 3

12.
Run Nutch / Solr
● Now run the nutch bash file
– ./nutch_start.bash
● Select the Logging option on the admin console
● Monitor for errors in Logging console
● The crawl should finish with no errors and the line
– Crawl finished: crawl
– In the crawl window

13.
Check Crawled Data
● Now we check the data that we have crawled
● In Admin Console window
– Set Core Selector to collection1
– Select the Query option
– Click execute query button
● You should now see some of the data that you have crawled

14.
Crawled Data
● Crawled data in solr query

15.
Crawled Data
● Thats your first simple crawl completed
● Further reading at
– http://nutch.apache.org
– http://lucene.apache.org/solr
● Now you can
– Add more urls to your seed.txt
– Increase the depth of your link search via options
● -depth
● -topN
– Modify your url filtering

16.
Contact Us
● Feel free to contact us at
– www.semtech-solutions.co.nz
– info@semtech-solutions.co.nz
● We offer IT project consultancy
● We are happy to hear about your problems
● You can just pay for those hours that you need
● To solve your problems