prosody
f0b2c026e542
util/id.lua

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util/id.lua @ 13552:f0b2c026e542

net.server_epoll: Improve efficiency of sending much buffered data Problem: The string slice operations when a lot of data gets buffered ends up being expensive and memory-consuming. We have util.dbuffer for precisely this kind of thing. I want to keep the behavior of writebuffer being upgraded from nil to a string to full buffer since the last step involves three table allocations, where the previous buffer method only used one. Avoiding those allocations for simple writes like white space keep alive feels like it would keep memory churn down. This work was started in 2020
author Kim Alvefur <zash@zash.se>
date Sat, 09 Nov 2024 00:37:15 +0100
parent 12975:d10957394a3c
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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 "prosody.util.random".bytes;
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12 local base64_encode = require "prosody.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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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 }