annotate mod_presence_dedup/mod_presence_dedup.lua @ 4282:281a864e7472

mod_pubsub_feeds: Don't skip publishing items after an existing one I encountered a feed which was backwards, such that older entries were considered first and then it would skip newer entries. This may however run into trouble if the feed contains more items than what's persisted in pubsub.
author Kim Alvefur <zash@zash.se>
date Mon, 30 Nov 2020 15:17:29 +0100
parents 19924a2c4a48
children
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f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
Kim Alvefur <zash@zash.se>
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1 local st = require "util.stanza";
f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
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2 local cache = require "util.cache";
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3 local add_filter = require "util.filters".add_filter;
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4
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5 local cache_size = module:get_option_number("presence_dedup_cache_size", 100);
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6
f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
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7 -- stanza equality tests
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8 local function attr_eq(a, b)
f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
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9 if a == b then return true; end -- unlikely but not impossible
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10 for k,v in pairs(a) do if b[k] ~= v then return false; end end
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11 for k,v in pairs(b) do if a[k] ~= v then return false; end end
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12 return true;
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13 end
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14
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15 local function st_eq(a, b)
f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
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16 if a == b then return true; end
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17 if type(b) ~= "table" then return false; end
f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
Kim Alvefur <zash@zash.se>
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18 if getmetatable(b) ~= st.stanza_mt then return false; end
f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
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19 if a.name ~= b.name then return false; end
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20 if #a ~= #b then return false; end
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21 if not attr_eq(a.attr, b.attr) then return false; end
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22 for i = 1, #a do if not st_eq(a[i], b[i]) then return false; end end
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23 return true;
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24 end
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25
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Kim Alvefur <zash@zash.se>
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26 local function dedup_presence(stanza, session)
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27 if session.presence_cache and session.presence
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28 and getmetatable(stanza) == st.stanza_mt and stanza.name == "presence"
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29 and stanza.attr.xmlns == nil and stanza.attr.from then
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30 local cached = session.presence_cache:get(stanza.attr.from);
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31 if st_eq(stanza, cached) then
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32 return nil;
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33 else
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34 session.presence_cache:set(stanza.attr.from, st.clone(stanza));
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35 end
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36 end
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Kim Alvefur <zash@zash.se>
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37 return stanza;
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38 end
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39
f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
Kim Alvefur <zash@zash.se>
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40 module:hook("presence/initial", function (event)
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19924a2c4a48 mod_presence_dedup: Remove unused variables [luacheck]
Kim Alvefur <zash@zash.se>
parents: 2155
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41 local session = event.origin;
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f24b02e0d706 mod_presence_dedup: Attempt at saving bandwith by deduplicating presence stanzas
Kim Alvefur <zash@zash.se>
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42 session.presence_cache = cache.new(cache_size);
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Kim Alvefur <zash@zash.se>
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43 add_filter(session, "stanzas/out", dedup_presence, 90);
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44 end);