Intelligent crawling and indexing using lucene


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Intelligent crawling and indexing using lucene

  1. 1. Intelligent Crawling and Indexingusing Lucene By Shiva Thatipelli Mohammad Zubair (Advisor)
  2. 2.  Contents Searching Indexing Lucene Indexing with Lucene Indexing Static and Dynamic Pages Extracting and Indexing Dynamic Pages Implementation Screens
  3. 3. Searching Looking up words in an index Factors Affecting Search Precision – How well the system can filter Speed Single, Multiple Phase queries, Results ranking, Sorting, Wild card queries, Range queries support
  4. 4. Indexing Sequential Search is bad (Not Scalable) Index speeds up selection Index is a special data structure which allows rapid searching. Different Index Implementations - B Trees - Hash Map
  5. 5. Search Process QueryDocs Docs Indexing API Hits Index
  6. 6. Lucene High-performance, full-featured text search engine library Written 100% in pure java Easy to use yet powerful API Jakarta Apache Product. Strong open source community support.
  7. 7. Why Lucene? Open source (Not proprietary) Easy to use, good documentation Interoperable - ex: Index generated by java can be used by VB, asp, perl application Powerful And Highly Scalable Index Format  Designed for interoperability  Well Documented  Resides on File System, RAM, custom store
  8. 8. Continued Algorithms  Efficient, fast and optimized• Incremental Indexing• Boolean Query, Fuzzy Query, Range Query, Multi Phrase Query, Wild Card Query etc…• Content Tagging – Documents as Collection of terms Heterogeneous documents - Useful when different set of metadata present for different mime types
  9. 9. Indexing With Lucene What type of documents can be indexed?  Any document from which text can be fetched and extracted over the net with a URL Uses Inverted Index - The index stores statistics about terms in order to make term-based search more efficient.
  10. 10. Indexing With Lucene Contd… HTML XLS WORD PDF extracted extracted extracted extracted Parser Parser Parser Parser Analyzer Index
  11. 11. Indexing Static and DynamicPages Static Pages which are HTML, XLS, WORD, PDF documents on web which can be easily crawled and indexed by search engines like Google and Yahoo. Static Pages over the internet can be passed into Lucene and indexed and searched with direct URLs. Dynamic Pages which are generated due to result of parameters submitted; like search results pages, Database hidden pages cannot be indexed with direct URLs. To index Dynamic Pages we need the parameters submitted by users to generate those pages.
  12. 12. Extracting and Indexing DynamicPages Extracting dynamic web pages which also can be called as database hidden pages needs some kind of input to generate the URLs To get the input parameters, we used of Apache Access logs which contain user request as URL. A sample entry in Apache access log is as follows: - - [31/Aug/2005:18:44:03 -0400] "GET /archon/servlet/search? formname=simple&fulltext=maly&group=subject&sor t=title HTTP/1.1" 200 9560
  13. 13. Extracting and Indexing DynamicPages Contd... It contains all the information like IP-address of the computer accessing the information, date, time information accessed, Method called, Request URL, HTTP version, and HTTP code. The Request URL is the one which has all the input parameters, in this case formname=simplefulltext=maly group=subject sort=title Results page is dynamic and dependent upon the parameters passed. A full URL like Can be generated from Request URL by appending Website address.
  14. 14. Indexing Dynamic Pages… Apache Logs Parse and generate URL Results page Could be any file type Analyzer Index
  15. 15. Implementation The above flow chart describes the way Apache logs are parsed and URLs are generated It shows how the Results pages are fetched and extracted from the URLs The Results page is sent for analysis then Lucene generates the index which will be used for future searches.
  16. 16. Demo
  17. 17.  Results: Hardware Environment Dedicated machine for indexing: No, but nominal usage at time of indexing. CPU: Intel x86 P4 2.8Ghz RAM: 512 DDR Drive configuration: IDE 7200rpm Software environment Lucene Version: 1.4 Java Version: 1..2 OS Version: Windows 2000 Apache Web server version 1.3 to 2.0 Location of index: local
  18. 18. Create file reads the access logs on local computer, generatesthe URLs, fetches and extracts the results page from the URLs andindexes them and stores in LuceneIndex folder.
  19. 19. Files extraction and IndexCreation
  20. 20. Searching at the prompt
  21. 21. Searching on the web
  22. 22. Results on the web
  23. 23. Conclusion It is very easy to implement efficient and powerful search engines using Lucene Lucene can be used to index dynamic pages and database hidden pages Web Server Access logs can be used to generate URLs and Java, Lucene API can be used to fetch and index database hidden pages. There are some security risks involved as we can reveal what users are doing what searches and other sensitive information .
  24. 24. Questions?