├── .gitignore
├── .jslintrc
├── .travis.yml
├── LICENCE
├── README.md
├── bin
└── simhash
├── lib
├── cli.js
└── simhash.js
├── package.json
└── test
├── sample1.txt
├── sample2.txt
├── test_cli.js
└── test_simhash.js
/.gitignore:
--------------------------------------------------------------------------------
1 | node_modules/
2 |
--------------------------------------------------------------------------------
/.jslintrc:
--------------------------------------------------------------------------------
1 | {
2 | "es6": true,
3 | "ass": false,
4 | "bitwise": false,
5 | "browser": false,
6 | "closure": false,
7 | "continue": false,
8 | "couch": false,
9 | "debug": false,
10 | "devel": false,
11 | "eqeq": false,
12 | "evil": false,
13 | "forin": false,
14 | "indent": 4,
15 | "maxerr": 50,
16 | "maxlen": false,
17 | "newcap": false,
18 | "node": true,
19 | "nomen": false,
20 | "passfail": false,
21 | "plusplus": false,
22 | "predef": [
23 | "angular",
24 | "$",
25 | ""
26 | ],
27 | "regexp": false,
28 | "rhino": false,
29 | "sloppy": false,
30 | "stupid": false,
31 | "sub": false,
32 | "todo": false,
33 | "unparam": false,
34 | "vars": false,
35 | "white": false
36 | }
37 |
--------------------------------------------------------------------------------
/.travis.yml:
--------------------------------------------------------------------------------
1 | language: node_js
2 | node_js:
3 | - "6.2.0"
4 |
--------------------------------------------------------------------------------
/LICENCE:
--------------------------------------------------------------------------------
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/README.md:
--------------------------------------------------------------------------------
1 | # node-simhash
2 |
3 | A simple command line tool for comparing text files using the simhash algorithm and contrasting with the jaccard index.
4 |
5 | [](https://travis-ci.org/sjhorn/node-simhash)
6 |
7 |
8 | ## References
9 |
10 | [Near duplicate detection (moz.com)](https://moz.com/devblog/near-duplicate-detection/)
11 |
12 | ## Installation
13 |
14 | ### If you have just clone this like then run the following
15 | ````
16 | npm install
17 | npm link
18 | ````
19 |
20 | Or if you would like to install globally
21 | ````
22 | npm install https://github.com/sjhorn/node-simhash -g
23 | ````
24 |
25 | ## Command line tool usage
26 |
27 | Using node
28 | ````
29 | simhash file1.txt file2.txt
30 |
31 | simhash https://file.com/page1.html https://file.com/page2.html
32 |
33 | ````
34 |
35 | ### Using lib
36 | ````js
37 | var simhash = require('node-simhash');
38 |
39 | simhash.compare(string1, string2);
40 |
41 | ````
42 |
43 | ### Methods
44 | #### .summary(file1, file2)
45 | Compare two text strings using both simhash and jaccard index and print a summary
46 |
47 | #### .compare(file1, file2)
48 | Compare two text strings using both simhash and jaccard index
49 |
50 |
51 | #### .hammingWeight(number)
52 |
53 | Count the binary ones in a number.
54 |
55 | #### .shingles(string, words_per_single=2)
56 |
57 | Convert string to set of shingles using the default of 2 words per shingle and tokenize using the natural libraries default tokenizer.
58 |
59 | #### .jaccardIndex(string1, string2)
60 |
61 | Compare two strings by tokeniseing and then compare the intersection of shingles to the union of shingles.
62 |
63 | #### .createBinaryString(number)
64 |
65 | Print a 32-bit number as a binary string of 32 characters
66 |
67 | #### .shingleHashList(set)
68 |
69 | Convert a set of shingles to a set of crc-32 hashes.
70 |
--------------------------------------------------------------------------------
/bin/simhash:
--------------------------------------------------------------------------------
1 | #!/usr/bin/env node
2 | require(require('path').resolve(__dirname, '../lib/cli'));
3 |
--------------------------------------------------------------------------------
/lib/cli.js:
--------------------------------------------------------------------------------
1 | void function() {
2 | 'use strict';
3 | var simhash = require('./simhash.js');
4 | var fetch = require('node-fetch');
5 | var fs = require('fs');
6 | var argv = require('yargs')
7 | .usage('Usage: $0 [options]')
8 | .demand(2)
9 | .example('$0 file1.htm http://t.com/file2.htm')
10 | .help('h')
11 | .alias('h', 'help')
12 | .argv;
13 |
14 | var f1 = argv._.shift();
15 | var f2 = argv._.shift();
16 |
17 | if(f1.startsWith("http") && f2.startsWith("http")) {
18 | console.log("Downloading files to compare...");
19 | fetch(f1).then(r1 => r1.text()).then(t1 => {
20 | fetch(f2).then(r2 => r2.text()).then(t2 => {
21 | simhash.summary(t1, t2);
22 | }).catch(e => console.error("Failed to download "+f2+" "+e))
23 | }).catch(e => console.error("Failed to download "+f1+" "+e));
24 | } else if(f1.startsWith("http") && !f2.startsWith("http")) {
25 | console.log("Downloading file to compare...");
26 | fetch(f1).then(r1 => r1.text()).then(t1 => {
27 | simhash.summary(t1, fs.readFileSync(f2, "utf8"));
28 | }).catch(e => console.error("Failed to download "+f1+" "+e));
29 | } else if(!f1.startsWith("http") && f2.startsWith("http")) {
30 | console.log("Downloading file to compare...");
31 | fetch(f2).then(r2 => r2.text()).then(t2 => {
32 | simhash.summary(fs.readFileSync(f1, "utf8"),t2);
33 | }).catch(e => console.error("Failed to download "+f2+" "+e));
34 | } else {
35 | simhash.summary(fs.readFileSync(f1, "utf8"), fs.readFileSync(f2, "utf8"));
36 | }
37 | }.call(this);
38 |
--------------------------------------------------------------------------------
/lib/simhash.js:
--------------------------------------------------------------------------------
1 | void function() {
2 | 'use strict';
3 | var crc32 = require('crc-32');
4 | var natural = require('natural');
5 | var NGrams = natural.NGrams;
6 |
7 | module.exports = {
8 | compare: compare,
9 | summary: summary,
10 | hammingWeight: hammingWeight,
11 | shingles: shingles,
12 | jaccardIndex: jaccardIndex,
13 | createBinaryString: createBinaryString,
14 | shingleHashList: shingleHashList
15 | }
16 |
17 | function compare(file1, file2) {
18 | return similarity(simhash(file1), simhash(file2));
19 | }
20 |
21 | function summary(file1, file2) {
22 | var hash1 = simhash(file1);
23 | var hash2 = simhash(file2);
24 | var simhashval = similarity(hash1, hash2);
25 | var jaccard = jaccardIndex(shingles(file1), shingles(file2));
26 | console.log("File1 simhash:", createBinaryString(hash1));
27 | console.log("File2 simhash:", createBinaryString(hash2));
28 | console.log( "Simhash similarity is "+simhashval+" (%d%% similar)", Math.round(simhashval * 100) );
29 | console.log( "Jaccard index is "+jaccard+" (%d%% similar)", Math.round(jaccard * 100) );
30 | }
31 |
32 | function hammingWeight(l) {
33 | var c;
34 | for(c = 0; l; c++) {
35 | l &= l-1;
36 | }
37 | return c;
38 | }
39 |
40 | function similarity(simhash1, simhash2) {
41 | return hammingWeight((simhash1 & simhash2)) / hammingWeight((simhash1 | simhash2));
42 | }
43 |
44 | function shingleHashList(str) {
45 | var list = [];
46 | for (var word of shingles(str, 2)) {
47 | list.push(crc32.str(word) & 0xffffffff);
48 | }
49 | return list;
50 | }
51 |
52 | function shingles(original, kshingles=2) {
53 | var shingles = new Set();
54 | for(var wordlist of NGrams.ngrams(original, kshingles, null, '[end]')) {
55 | shingles.add(wordlist.join(" "));
56 | }
57 | return shingles;
58 | }
59 |
60 | function simhash(str) {
61 | var shingles = shingleHashList(str);
62 | var mask = 0x1;
63 | var simhash = 0x0;
64 | for(var i = 0; i < 64; i++) {
65 | var sim = 0;
66 | for(var s of shingles) {
67 | sim += ((s & mask) == mask) ? 1 : -1;
68 | }
69 | simhash |= (sim > 0 ? mask : 0x0);
70 | mask <<= 1;
71 | }
72 | return simhash;
73 | }
74 |
75 | function jaccardIndex(set1, set2) {
76 | var total = set1.size + set2.size;
77 | var intersection = 0;
78 | for(var shingle of set1 ) {
79 | if(set2.has(shingle)) {
80 | intersection++;
81 | }
82 | }
83 | var union = total - intersection;
84 | return intersection / union;
85 | }
86 |
87 | function createBinaryString (nMask) {
88 | for (var nFlag = 0, nShifted = nMask, sMask = ""; nFlag < 32;
89 | nFlag++, sMask += String(nShifted >>> 31), nShifted <<= 1);
90 | return sMask;
91 | }
92 |
93 | }.call(this);
94 |
--------------------------------------------------------------------------------
/package.json:
--------------------------------------------------------------------------------
1 | {
2 | "name": "node-simhash",
3 | "version": "0.1.0",
4 | "description": "Command Line tool that compares two text files using simhash",
5 | "homepage": "https://github.com/sjhorn/node-simhash",
6 | "keywords": [
7 | "simhash",
8 | "jaccard index",
9 | "compare text"
10 | ],
11 | "repository": {
12 | "type": "git",
13 | "url": "git://github.com/sjhorn/node-simhash.git"
14 | },
15 | "bugs": "https://github.com/sjhorn/node-simhash/issues",
16 | "engines": {
17 | "node": "6.2.x"
18 | },
19 | "main": "lib/simhash.js",
20 | "directories": {
21 | "bin": "bin",
22 | "lib": "lib",
23 | "test": "test"
24 | },
25 | "dependencies": {
26 | "crc-32": "~0.3.0",
27 | "natural": "0.4.0",
28 | "node-fetch": "^1.5.3",
29 | "yargs": "^4.7.1"
30 | },
31 | "devDependencies": {
32 | "nodeunit": "^0.9.1"
33 | },
34 | "bin": {
35 | "simhash": "bin/simhash"
36 | },
37 | "scripts": {
38 | "test": "nodeunit"
39 | },
40 | "licenses": [
41 | {
42 | "type": "Apache",
43 | "url": "https://github.com/sjhorn/node-simhash/blob/master/LICENSE"
44 | }
45 | ],
46 | "author": "Scott Horn"
47 | }
48 |
--------------------------------------------------------------------------------
/test/sample1.txt:
--------------------------------------------------------------------------------
1 | A simple string that,
2 |
3 | spans somelines
4 |
5 | with some ! punctuations
6 |
7 | ***hello.
8 |
--------------------------------------------------------------------------------
/test/sample2.txt:
--------------------------------------------------------------------------------
1 | A simple string that,
2 |
3 | spans
4 |
5 | with some ! punctuations
6 |
7 | ***hello.
8 |
--------------------------------------------------------------------------------
/test/test_cli.js:
--------------------------------------------------------------------------------
1 | var exec = require('child_process').exec;
2 |
3 | exports['Cli shows Help'] = function(test) {
4 | exec('node lib/cli.js -h', function(error, stdout, stderr) {
5 | if (error != null) {
6 | test.ok(false, "cli does not successfully show help");
7 | }
8 | test.done();
9 | })
10 | }
11 |
12 | exports['Cli Compare Files'] = function(test) {
13 | exec('node lib/cli.js test/sample1.txt test/sample2.txt', function(error, stdout, stderr) {
14 | if (error != null) {
15 | test.ok(false, "cli does not successfully compare files");
16 | } else {
17 | test.ok(stdout.indexOf("Simhash similarity is") != -1, "Failed to display summary");
18 | }
19 | test.done();
20 | })
21 | }
22 |
23 | exports['Cli Compare sites'] = function(test) {
24 | exec('node lib/cli.js https://raw.githubusercontent.com/sjhorn/node-simhash/master/LICENCE https://raw.githubusercontent.com/sjhorn/node-simhash/master/LICENCE', function(error, stdout, stderr) {
25 | if (error != null) {
26 | test.ok(false, "cli does not successfully compare pages");
27 | } else {
28 | test.ok(stdout.indexOf("Simhash similarity is") != -1, "Failed to display summary");
29 | }
30 | test.done();
31 | })
32 | }
33 |
--------------------------------------------------------------------------------
/test/test_simhash.js:
--------------------------------------------------------------------------------
1 | var simhash = require('../lib/simhash.js');
2 | var fs = require('fs');
3 |
4 | exports.compareSmallString = function(test) {
5 | test.equal(simhash.compare('I am working', 'I am working'), 1);
6 | test.done();
7 | }
8 |
9 | exports.compareSameFile = function(test) {
10 | var file1 = fs.readFileSync("test/sample1.txt", "utf8");
11 | test.equal(simhash.compare(file1, file1), 1);
12 | test.done();
13 | }
14 |
15 | exports.compareSimilarFile = function(test) {
16 | var file1 = fs.readFileSync("test/sample1.txt", "utf8");
17 | var file2 = fs.readFileSync("test/sample2.txt", "utf8");
18 | var estimate = Math.round(simhash.compare(file1, file2) * 100);
19 | test.equal(estimate, 67);
20 | test.done();
21 | }
22 |
--------------------------------------------------------------------------------