prosody
22066b02887f
util/id.lua

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util/id.lua @ 12781:22066b02887f

util.startup: Provide a common Lua 5.3+ math.type() for Lua 5.2 Code deduplication
author Kim Alvefur <zash@zash.se>
date Wed, 19 Oct 2022 16:25:05 +0200
parent 12111:f8d280215633
child 12975:d10957394a3c
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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9546c629289b util.id: New util for producing random identifiers of varying sizes
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1 -- Prosody IM
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2 -- Copyright (C) 2008-2017 Matthew Wild
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3 -- Copyright (C) 2008-2017 Waqas Hussain
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4 -- Copyright (C) 2008-2017 Kim Alvefur
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5 --
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6 -- This project is MIT/X11 licensed. Please see the
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7 -- COPYING file in the source package for more information.
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8 --
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9
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10 local s_gsub = string.gsub;
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11 local random_bytes = require "util.random".bytes;
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12 local base64_encode = require "util.encodings".base64.encode;
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13
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14 local b64url = { ["+"] = "-", ["/"] = "_", ["="] = "" };
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15 local function b64url_random(len)
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16 return (s_gsub(base64_encode(random_bytes(len)), "[+/=]", b64url));
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17 end
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18
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19 return {
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20 -- sizes divisible by 3 fit nicely into base64 without padding==
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21
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f8d280215633 util.id: Add a 'tiny' variant
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22 -- for short lived things with low risk of collisions
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23 tiny = function() return b64url_random(3); end;
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24
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25 -- close to 8 bytes, should be good enough for relatively short lived or uses
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26 -- scoped by host or users, half the size of an uuid
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27 short = function() return b64url_random(9); end;
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28
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29 -- more entropy than uuid at 2/3 the size
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30 -- should be okay for globally scoped ids or security token
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31 medium = function() return b64url_random(18); end;
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32
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33 -- as long as an uuid but MOAR entropy
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34 long = function() return b64url_random(27); end;
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35
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36 -- pick your own adventure
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37 custom = function (size)
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38 return function () return b64url_random(size); end;
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39 end;
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40 }