The UzunExt Approach is an efficient and effective web content extractor. The approach has two different libraries for extraction and learning process.
A DOM Tree can be used for extraction from web pages. However, this tree takes all elements in a web page into consideration for this task. UzunExt extracts web content quickly by using string methods and additional information without utilizing DOM Tree. The following method is the extraction stage of this algorithm.
List<string> Extract(string tagname, string source, int startIndex, int endtag_cnt, bool repeative, ESMAJ.SearchAlgoritms.SearchAlgorithm sa);
//usage
UzunExtAlgorithmLib.UzunExtAlgorithm.Extract(tagname, source, 0, -1, false, (ESMAJ.SearchAlgoritms.SearchAlgorithm)34);Parameters:
- tagname is an element for using extraction process. For example:
- source is a Web page that contains tagname.
- startindex is approximate starting index for searching.
- endtag_Cnt is the number of element name of tagname.
- repetitive is used to break the loop for stopping extraction process.
- Search algorithms determine pattern matching algorithm. Algorithms: ApostolicoCrochemore, ApostolicoGiancarlo, BackwardNondeterministicDawgMatching, BackwardOracleMatching, BerryRavindran, BoyerMoore, BruteForce, Colussi, DeterministicFiniteAutomaton, ForwardDawgMatching, GalilGiancarlo, Horspool,KarpRabin, KMPSkipSearch, KnuthMorrisPratt, MaximalShift, MorrisPratt, NotSoNaive, OptimalMismatch, QuickSearch, Raita, ReverseColussi, ReverseFactor, ShiftOr, Simon,SkipSearch, Smith, StringMatchingonOrderedAlphabets, TunedBoyerMoore, TurboBM, TurboReverseFactor, TwoWay, ZhuTakaoka, NET_IndexOf, NET_IndexOf_Ordinal
This library is used for determining parameters of startIndex, endtag_cnt and repeative. You can set situations of these parameters in contructor of class.
- startIndex; //-1:learn1, -2:learn2, >= 0, -3: close
- innerTagL; //-1:learn, >= 0, -2: close
- int repetitionL; //-1:learn, 1:fixed false; 2:fixed true, -2: close (false), -3: close (true)
UzunExtAlgorithmLib.LearningLayer _LL = new UzunExtAlgorithmLib.LearningLayer(learn_StartingPos, learn_ITC, learn_Repetition);If values of these parameters -1, -1, -1, respecetively; the algorithm decides on appropriate values in a crawling process. For understading the execution of this method, yo can examine the directory : UzunExt/UzunExtTester/DatasetGenerator/.
A Novel Web Scraping Approach Using the Additional Information Obtained from Web Pages. Uzun, E. IEEE Access, 8: 61726-61740. 2020.
Evaluation of Hap, AngleSharp and HtmlDocument in web content extraction. Uzun, E.; Buluş, H., N.; Doruk, A.; and Özhan, E. In International Scientific Conference’2017 (UNITECH’17), volume 2, pages 275-278, 2017.
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