util/caps.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2010 Matthew Wild
   3 -- Copyright (C) 2008-2010 Waqas Hussain
   4 --
   5 -- This project is MIT/X11 licensed. Please see the
   6 -- COPYING file in the source package for more information.
   7 --
   8
   9 local base64 = require "util.encodings".base64.encode;
  10 local sha1 = require "util.hashes".sha1;
  11
  12 local t_insert, t_sort, t_concat = table.insert, table.sort, table.concat;
  13 local ipairs = ipairs;
  14
  15 local _ENV = nil;
  16
  17 local function calculate_hash(disco_info)
  18         local identities, features, extensions = {}, {}, {};
  19         for _, tag in ipairs(disco_info) do
  20                 if tag.name == "identity" then
  21                         t_insert(identities, (tag.attr.category or "").."\0"..(tag.attr.type or "").."\0"..(tag.attr["xml:lang"] or "").."\0"..(tag.attr.name or ""));
  22                 elseif tag.name == "feature" then
  23                         t_insert(features, tag.attr.var or "");
  24                 elseif tag.name == "x" and tag.attr.xmlns == "jabber:x:data" then
  25                         local form = {};
  26                         local FORM_TYPE;
  27                         for _, field in ipairs(tag.tags) do
  28                                 if field.name == "field" and field.attr.var then
  29                                         local values = {};
  30                                         for _, val in ipairs(field.tags) do
  31                                                 val = #val.tags == 0 and val:get_text();
  32                                                 if val then t_insert(values, val); end
  33                                         end
  34                                         t_sort(values);
  35                                         if field.attr.var == "FORM_TYPE" then
  36                                                 FORM_TYPE = values[1];
  37                                         elseif #values > 0 then
  38                                                 t_insert(form, field.attr.var.."\0"..t_concat(values, "<"));
  39                                         else
  40                                                 t_insert(form, field.attr.var);
  41                                         end
  42                                 end
  43                         end
  44                         t_sort(form);
  45                         form = t_concat(form, "<");
  46                         if FORM_TYPE then form = FORM_TYPE.."\0"..form; end
  47                         t_insert(extensions, form);
  48                 end
  49         end
  50         t_sort(identities);
  51         t_sort(features);
  52         t_sort(extensions);
  53         if #identities > 0 then identities = t_concat(identities, "<"):gsub("%z", "/").."<"; else identities = ""; end
  54         if #features > 0 then features = t_concat(features, "<").."<"; else features = ""; end
  55         if #extensions > 0 then extensions = t_concat(extensions, "<"):gsub("%z", "<").."<"; else extensions = ""; end
  56         local S = identities..features..extensions;
  57         local ver = base64(sha1(S));
  58         return ver, S;
  59 end
  60
  61 return {
  62         calculate_hash = calculate_hash;
  63 };