Add uri decode. Closes #16

lib/decode.js

@@ -0,0 +1,120 @@
+'use strict';
+
+// Adapted from:
+// Copyright (c) 2017-2019 Justin Ridgewell, MIT Licensed, https://github.com/jridgewell/safe-decode-string-component
+// Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>, MIT Licensed, http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
+
+
+const internals = {};
+
+
+exports.decode = function (string) {
+
+    let percentPos = string.indexOf('%');
+    if (percentPos === -1) {
+        return string;
+    }
+
+    let decoded = '';
+    let last = 0;
+    let codepoint = 0;
+    let startOfOctets = percentPos;
+    let state = internals.utf8.accept;
+
+    while (percentPos > -1 &&
+        percentPos < string.length) {
+
+        const high = internals.resolveHex(string[percentPos + 1], 4);
+        const low = internals.resolveHex(string[percentPos + 2], 0);
+        const byte = high | low;
+        const type = internals.utf8.data[byte];
+        state = internals.utf8.data[256 + state + type];
+        codepoint = (codepoint << 6) | (byte & internals.utf8.data[364 + type]);
+
+        if (state === internals.utf8.accept) {
+            decoded += string.slice(last, startOfOctets);
+            decoded += codepoint <= 0xFFFF
+                ? String.fromCharCode(codepoint)
+                : String.fromCharCode(0xD7C0 + (codepoint >> 10), 0xDC00 + (codepoint & 0x3FF));
+
+            codepoint = 0;
+            last = percentPos + 3;
+            percentPos = string.indexOf('%', last);
+            startOfOctets = percentPos;
+            continue;
+        }
+
+        if (state === internals.utf8.reject) {
+            return null;
+        }
+
+        percentPos += 3;
+
+        if (percentPos >= string.length ||
+            string[percentPos] !== '%') {
+
+            return null;
+        }
+    }
+
+    return decoded + string.slice(last);
+};
+
+
+internals.resolveHex = function (char, shift) {
+
+    const i = internals.hex[char];
+    return i === undefined ? 255 : i << shift;
+};
+
+
+internals.hex = {
+    '0': 0, '1': 1, '2': 2, '3': 3, '4': 4,
+    '5': 5, '6': 6, '7': 7, '8': 8, '9': 9,
+    'a': 10, 'A': 10, 'b': 11, 'B': 11, 'c': 12,
+    'C': 12, 'd': 13, 'D': 13, 'e': 14, 'E': 14,
+    'f': 15, 'F': 15
+};
+
+
+internals.utf8 = {
+    accept: 12,
+    reject: 0,
+    data: [
+
+        // Maps bytes to character to a transition
+
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+        2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+        3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+        3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+        4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+        6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 7, 7,
+        10, 9, 9, 9, 11, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+
+        // Maps a state to a new state when adding a transition
+
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        12, 0, 0, 0, 0, 24, 36, 48, 60, 72, 84, 96,
+        0, 12, 12, 12, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 24, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 24, 24, 24, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 24, 24, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 48, 48, 48, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 48, 48, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 48, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+
+        // Maps the current transition to a mask that needs to apply to the byte
+
+        0x7F, 0x3F, 0x3F, 0x3F, 0x00, 0x1F, 0x0F, 0x0F, 0x0F, 0x07, 0x07, 0x07
+    ]
+};

lib/index.d.ts

@@ -173,6 +173,15 @@ export namespace ip {
 
 export namespace uri {
 
+    /**
+     * Faster version of decodeURIComponent() that does not throw.
+     * 
+     * @param string - the URL string to decode.
+     * 
+     * @returns the decoded string or null if invalid.
+     */
+    function decode(string: string): string | null;
+
     /**
      * Generates a regular expression used to validate URI addresses.
      *

lib/index.js

@@ -1,5 +1,6 @@
 'use strict';
 
+const Decode = require('./decode');
 const Domain = require('./domain');
 const Email = require('./email');
 const Errors = require('./errors');
@@ -46,6 +47,7 @@ module.exports = {
         regex: Ip.regex
     },
     uri: {
+        decode: Decode.decode,
         regex: Uri.regex
     }
 };

test/decode.js

@@ -0,0 +1,102 @@
+'use strict';
+
+const Address = require('..');
+const Code = require('@hapi/code');
+const Lab = require('@hapi/lab');
+
+
+const internals = {};
+
+
+const { describe, it } = exports.lab = Lab.script();
+const expect = Code.expect;
+
+
+describe('uri.decode()', () => {
+
+    it('decodes URI strings', () => {
+
+        const strings = [
+            '',
+            'abcd',
+            '1+2+3+4',
+            'a b c d',
+            '=x',
+            '%25',
+            'p%C3%A5ss',
+            '%61+%4d%4D',
+            '\uFEFFtest',
+            '\uFEFF',
+            '%EF%BB%BFtest',
+            '%EF%BB%BF',
+            '%C2%B5',
+            '†',
+            '/a/b%2Fc',
+            '¢™💩',
+            encodeURI('¢™💩')
+        ];
+
+        for (const string of strings) {
+            expect(Address.uri.decode(string)).to.equal(decodeURIComponent(string));
+        }
+    });
+
+    it('handles invalid strings', () => {
+
+        const strings = [
+            '%',
+            '%2',
+            '%%25%%',
+            '%ab',
+            '%ab%ac%ad',
+            'f%C3%A5il%',
+            'f%C3%A5%il',
+            '%f%C3%A5il',
+            'f%%C3%%A5il',
+            '%C2%B5%',
+            '%%C2%B5%',
+            '%E0%A4%A',
+            '/a/b%"Fc',
+            '64I%C8yY3wM9tB89x2S~3Hs4AXz3TKPS',
+            'l3k%Dbbbxn.L5P2ilI-tLxUgndaWnr81',
+            'fum3GJU-DLBgO%dehn%MGDsM-jn-p-_Q',
+            'AWgvg5oEgIJoS%eD28Co4koKtu346v3j',
+            'k3%c4NVrqbGf~8IeQyDueGVwV1a8_vb4',
+            'QlW8P%e9ARoU4chM4ckznRJWP-6RmIL5',
+            'h7w6%dfcx4k.EYkPlGey._b%wfOb-Y1q',
+            'zFtcAt%ca9ITgiTldiF_nfNlf7a0a578',
+            '.vQD.nCmjJNEpid%e5KglS35Sv-97GMk',
+            '8qYKc_4Zx%eA.1C6K99CtyuN4_Xl8edp',
+            '.Y4~dvjs%D7Qqhy8wQz3O~mLuFXGNG2T',
+            'kou6MHS%f3AJTpe8.%eOhfZptvsGmCAC',
+            '-yUdrHiMrRp1%DfvjZ.vkn_dO9p~q07A',
+            'e6BF%demc0%52iqSGOPL3kvYePf-7LIH',
+            'Aeo_4FxaGyC.w~F1TAAK9uYf-y._m%ca',
+            'z0krVTLPXhcqW~1PxkEmke0CmNcIT%EE',
+            '3KqqzjaF.6QH6M5gm5PnV5iR3X99n%Cb',
+            'Nl_0qJEX6ZBVK2E3qvFNL0sMJzpxK%DF',
+            'WKj35GkCYJ~ZF_mkKZnPBQzo2CJBj%D6',
+            'ym8WNqRjaxrK9CEf.Y.Twn0he8.6b%ca',
+            'S4q0CjXZW5aWtnGiJl.svb7ow8HG6%c9',
+            '0iL5JYG96IjiQ1PHfxTobQOjaqv7.%d3',
+            '3OzV6xpZ2xmPxSBoMTTC_LcFpnE0M%Ea',
+            'dvQN9Ra2UoWefWY.MEZXaD69bUHNc%Cd'
+        ];
+
+        for (const string of strings) {
+            expect(() => decodeURIComponent(string)).to.throw();
+            expect(Address.uri.decode(string)).to.be.null();
+        }
+    });
+
+    it('decodes every character', () => {
+
+        const chars = [];
+        for (let i = 0; i < 256; ++i) {
+            chars.push(encodeURI(String.fromCharCode(i)));
+        }
+
+        const string = chars.join('a1$#');
+        expect(Address.uri.decode(string)).to.equal(decodeURIComponent(string));
+    });
+});

test/domain.js

@@ -1,4 +1,4 @@
-'use strict';
+'use strict';
 
 const Punycode = require('punycode');
 

test/email.js

@@ -1,4 +1,4 @@
-'use strict';
+'use strict';
 
 const Punycode = require('punycode');
 

test/index.ts

@@ -137,6 +137,16 @@ expect.error(Address.ip.regex({ version: 'x' }));
 expect.error(Address.ip.regex({ version: ['x'] }));
 
 
+// uri.decode()
+
+Address.uri.decode('%25a%25');
+
+expect.type<string | null>(Address.uri.decode(''));
+
+expect.error(Address.uri.decode());
+expect.error(Address.uri.decode(123));
+
+
 // uri.regex()
 
 Address.uri.regex();

test/uri.js

@@ -1,4 +1,4 @@
-'use strict';
+'use strict';
 
 const Address = require('..');
 const Code = require('@hapi/code');