mod_cache_c2s_caps/mod_cache_c2s_caps.lua

   1 local st_iq = require "util.stanza".iq;
   2 local uuid_gen = require "util.uuid".generate;
   3 local calculate_hash = require "util.caps".calculate_hash;
   4
   5 -- Map of jid..node, to avoid querying the same client multiple times for the same value.
   6 local in_flight_iqs = {}
   7
   8 -- Some clients (*ahem* poezio…) don’t include the @node in their result iq.
   9 local iq_node_map = {}
  10
  11 assert(module.send_iq, "This module is not compatible with this version of Prosody.");
  12
  13 local function iq_result_handler(event)
  14         local origin, stanza = event.origin, event.stanza;
  15
  16         local query = stanza:get_child("query", "http://jabber.org/protocol/disco#info");
  17         if not query then
  18                 origin.log("debug", "Wrong iq payload in disco#info result: %s", stanza);
  19                 origin.caps_cache = nil;
  20                 return;
  21         end
  22
  23         local from = stanza.attr.from;
  24         local id = stanza.attr.id;
  25         local node_string = query.attr.node;
  26         local node_query = iq_node_map[from..id];
  27         if node_string == nil then
  28                 node_string = node_query;
  29                 query.attr.node = node_query;
  30         end
  31         iq_node_map[from..id] = nil;
  32
  33         if node_string ~= node_query then
  34                 origin.log("debug", "Wrong node for our disco#info query, expected %s, received %s", node_string, node_query);
  35                 origin.caps_cache = nil;
  36                 return;
  37         end
  38
  39         local node, ver = node_query:match("([^#]+)#([^#]+)");
  40         local hash = calculate_hash(query)
  41         if ver ~= hash then
  42                 origin.log("debug", "Wrong hash for disco#info: %s ~= %s", ver, hash);
  43                 origin.caps_cache = nil;
  44                 return;
  45         end
  46
  47         origin.caps_cache = query;
  48         origin.log("info", "Stored caps %s", ver);
  49         module:fire_event("c2s-capabilities-changed", { origin = origin });
  50         return true;
  51 end
  52
  53 local function iq_error_handler(err)
  54         local origin = err.context.origin;
  55         if origin ~= nil then
  56                 origin.caps_cache = nil;
  57                 module:fire_event("c2s-capabilities-changed", { origin = origin });
  58         end
  59 end
  60
  61 local function presence_stanza_handler(event)
  62         local origin, stanza = event.origin, event.stanza;
  63
  64         local from = stanza.attr.from;
  65         if stanza.attr.to ~= nil then
  66                 return;
  67         end
  68
  69         local caps = stanza:get_child("c", "http://jabber.org/protocol/caps");
  70         if caps == nil then
  71                 origin.log("debug", "Presence without caps received, skipping");
  72                 return;
  73         end
  74
  75         local hash = caps.attr.hash;
  76         local node = caps.attr.node;
  77         local ver = caps.attr.ver;
  78         if not hash or not node or not ver then
  79                 return;
  80         end
  81         if hash ~= "sha-1" then
  82                 origin.log("warn", "Non-SHA-1 caps received: %s", hash);
  83                 return;
  84         end
  85
  86         local node_query = node.."#"..ver;
  87         if (origin.caps_cache and origin.caps_cache.attr.node == node_query) or in_flight_iqs[from..node_query] ~= nil then
  88                 origin.log("debug", "Already requested these caps, skipping");
  89                 return;
  90         end
  91
  92         origin.log("debug", "Received presence with SHA-1 caps %s, querying disco#info", node_query);
  93
  94         local id = uuid_gen();
  95         iq_node_map[from..id] = node_query
  96         local iq = st_iq({ type = "get", from = module.host, to = from, id = id })
  97                 :tag("query", { xmlns = "http://jabber.org/protocol/disco#info", node = node_query });
  98         in_flight_iqs[from..node_query] = true;
  99         module:send_iq(iq, origin)
 100                 :next(iq_result_handler, iq_error_handler)
 101                 :finally(function () in_flight_iqs[from..node_query] = nil; end)
 102 end
 103
 104 -- Handle only non-directed presences for now.
 105 module:hook("pre-presence/bare", presence_stanza_handler);