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mod_presence_dedup/mod_presence_dedup.lua @ 3656:3e0f4d727825
mod_vcard_muc: Add an alternative method of signaling avatar change
When the avatar has been changed, a signal is sent that the room
configuration has changed. Clients then do a disco#info query to find
the SHA-1 of the new avatar. They can then fetch it as before, or not if
they have it cached already.
This is meant to be less disruptive than signaling via presence, which
caused problems for some clients.
If clients transition to the new method, the old one can eventually be removed.
The namespace is made up while waiting for standardization.
Otherwise it is very close to what's described in
https://xmpp.org/extensions/inbox/muc-avatars.html
author | Kim Alvefur <zash@zash.se> |
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date | Sun, 25 Aug 2019 20:46:43 +0200 |
parent | 3445:19924a2c4a48 |
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local st = require "util.stanza"; local cache = require "util.cache"; local add_filter = require "util.filters".add_filter; local cache_size = module:get_option_number("presence_dedup_cache_size", 100); -- stanza equality tests local function attr_eq(a, b) if a == b then return true; end -- unlikely but not impossible for k,v in pairs(a) do if b[k] ~= v then return false; end end for k,v in pairs(b) do if a[k] ~= v then return false; end end return true; end local function st_eq(a, b) if a == b then return true; end if type(b) ~= "table" then return false; end if getmetatable(b) ~= st.stanza_mt then return false; end if a.name ~= b.name then return false; end if #a ~= #b then return false; end if not attr_eq(a.attr, b.attr) then return false; end for i = 1, #a do if not st_eq(a[i], b[i]) then return false; end end return true; end local function dedup_presence(stanza, session) if session.presence_cache and session.presence and getmetatable(stanza) == st.stanza_mt and stanza.name == "presence" and stanza.attr.xmlns == nil and stanza.attr.from then local cached = session.presence_cache:get(stanza.attr.from); if st_eq(stanza, cached) then return nil; else session.presence_cache:set(stanza.attr.from, st.clone(stanza)); end end return stanza; end module:hook("presence/initial", function (event) local session = event.origin; session.presence_cache = cache.new(cache_size); add_filter(session, "stanzas/out", dedup_presence, 90); end);