node-carrot2 - Carrot2 DCS implementation for Node.js

This library requires the Carrot2 Document Clustering Server - an open source clustering engine available at http://project.carrot2.org/index.html. Installation instructions and configuration can be found at http://project.carrot2.org/documentation.html. Carrot2 was originally designed for clustering search results from web queries, and thus uses a "search result" metaphor (which we've upheld), but it can also be used for any small (a few thousand) collection of documents.

Install the package:

npm install carrot2

Basic Use

The basic use of node-carrot2 involves providing a set of documents to the cluster server and receiving a SearchResult object through a callback. For a complete example, refer to examples/basic.js.

Step 1: Include the package

var carrot2 = require('carrot2');

Step 2: Create an instance of the DCS interface

DocumentClusteringServer can accept an optional parameter object with host and port properties.

var dcs = new carrot2.DocumentClusteringServer(params);

Step 3: Create a SearchResult object and populate it with documents

Each document contains an id, title, url, snippet, and optional custom parameters:

var sr = new carrot2.SearchResult();
sr.addDocument("ID", "Title", "http://www.site.com/", "This is a snippet.", {my_key1:my_value1, my_key2:my_value2});

Step 4: Call the cluster method

dcs.cluster(sr, {algorithm:'lingo'}, [ 
        {key:"LingoClusteringAlgorithm.desiredClusterCountBase", value:10},
        {key:"LingoClusteringAlgorithm.phraseLabelBoost", value:1.0}
], function(err, sr) {
    if (err) console.log(err);
    var cluster = sr.clusters;
});

For a complete list of customizable Carrot2 attributes, refer to the Component documentation: http://download.carrot2.org/head/manual/index.html#chapter.components.

NOTE: Currently the DCS parameters object supports algorithm, ids (set of document id's to use - defaults to all), and max (maximum number of documents to supply). Possible algorithm's are:

• lingo — Lingo Clustering (default)
• stc — Suffix Tree Clustering
• kmeans — Bisecting k-means
• url — By URL Clustering
• source — By Source Clustering

External Use

Alternatively, you can cluster an external search engine results by suppling a query string instead of a SearchResult to the cluster method. For a complete example, refer to examples/external.js.

dcs.cluster('my query', {algorithm:'stc', source:"bing-web"}, [ 
        {key:"LingoClusteringAlgorithm.desiredClusterCountBase", value:10},
        {key:"LingoClusteringAlgorithm.phraseLabelBoost", value:1.0}
], function(err, sr) {
    if (err) console.log(err);
	var cluster = sr.clusters;
});

NOTE: The DCS parameters object supports source (search engine to use), and results (number of search results to grab from source). Possible external sources include:

• etools — eTools Metasearch Engine
• bing-web — Bing Search
• boss-web — Yahoo Web Search
• wiki — Wikipedia Search (with Yahoo Boss)
• boss-images — Yahoo Image Search
• boss-news — Yahoo Boss News Search
• pubmed — PubMed medical database
• indeed — Jobs from indeed.com
• xml — XML
• google-desktop — Google Desktop search
• solr — Solr Search Engine

Results

A SearchResult object returned in a cluster callback looks like:

{ query: 'seattle',
  cap: 100,
  id_increment: 0,
  documents: [ ... ],
  documentHash: { ... },
  idHash: {},
  clusters: 
   [ { id: '[\'Washington\']',
	  size: 13,
	  score: 39.551955526331575,
	  phrases: [ 'Washington' ],
	  documents: 
	   [ { id: 1 },
	     { id: 4 },
	     { id: 25 },
	     { id: 26 },
	     { id: 36 },
	     { id: 39 },
	     { id: 45 },
	     { id: 47 },
	     { id: 64 },
	     { id: 71 },
	     { id: 73 },
	     { id: 75 },
	     { id: 95 } ],
	  attributes: { score: 39.551955526331575 } }
	,

...
	     
  clusterHash: 
   { '[\'Washington\']': 
      { id: '[\'Washington\']',
	  size: 13,
	  score: 39.551955526331575,
	  phrases: [ 'Washington' ],
	  documents: 
	   [ { id: 1 },
	     { id: 4 },
	     { id: 25 },
	     { id: 26 },
	     { id: 36 },
	     { id: 39 },
	     { id: 45 },
	     { id: 47 },
	     { id: 64 },
	     { id: 71 },
	     { id: 73 },
	     { id: 75 },
	     { id: 95 } ],
	  attributes: { score: 39.551955526331575 } },
     
...
     
    } 
}

For detailed documentation on Carrot2 JSON output reference http://download.carrot2.org/head/manual/index.html#section.architecture.output-json.

License

See the file