util/xml.lua

   1
   2 local st = require "util.stanza";
   3 local lxp = require "lxp";
   4 local t_insert = table.insert;
   5 local t_remove = table.remove;
   6
   7 local _ENV = nil;
   8 -- luacheck: std none
   9
  10 local parse_xml = (function()
  11         local ns_prefixes = {
  12                 ["http://www.w3.org/XML/1998/namespace"] = "xml";
  13         };
  14         local ns_separator = "\1";
  15         local ns_pattern = "^([^"..ns_separator.."]*)"..ns_separator.."?(.*)$";
  16         return function(xml)
  17                 --luacheck: ignore 212/self
  18                 local handler = {};
  19                 local stanza = st.stanza("root");
  20                 local namespaces = {};
  21                 local prefixes = {};
  22                 function handler:StartNamespaceDecl(prefix, url)
  23                         if prefix ~= nil then
  24                                 t_insert(namespaces, url);
  25                                 t_insert(prefixes, prefix);
  26                         end
  27                 end
  28                 function handler:EndNamespaceDecl(prefix)
  29                         if prefix ~= nil then
  30                                 -- we depend on each StartNamespaceDecl having a paired EndNamespaceDecl
  31                                 t_remove(namespaces);
  32                                 t_remove(prefixes);
  33                         end
  34                 end
  35                 function handler:StartElement(tagname, attr)
  36                         local curr_ns,name = tagname:match(ns_pattern);
  37                         if name == "" then
  38                                 curr_ns, name = "", curr_ns;
  39                         end
  40                         if curr_ns ~= "" then
  41                                 attr.xmlns = curr_ns;
  42                         end
  43                         for i=1,#attr do
  44                                 local k = attr[i];
  45                                 attr[i] = nil;
  46                                 local ns, nm = k:match(ns_pattern);
  47                                 if nm ~= "" then
  48                                         ns = ns_prefixes[ns];
  49                                         if ns then
  50                                                 attr[ns..":"..nm] = attr[k];
  51                                                 attr[k] = nil;
  52                                         end
  53                                 end
  54                         end
  55                         local n = {}
  56                         for i=1,#namespaces do
  57                                 n[prefixes[i]] = namespaces[i];
  58                         end
  59                         stanza:tag(name, attr, n);
  60                 end
  61                 function handler:CharacterData(data)
  62                         stanza:text(data);
  63                 end
  64                 function handler:EndElement()
  65                         stanza:up();
  66                 end
  67                 local parser = lxp.new(handler, "\1");
  68                 local ok, err, line, col = parser:parse(xml);
  69                 if ok then ok, err, line, col = parser:parse(); end
  70                 --parser:close();
  71                 if ok then
  72                         return stanza.tags[1];
  73                 else
  74                         return ok, err.." (line "..line..", col "..col..")";
  75                 end
  76         end;
  77 end)();
  78
  79 return {
  80         parse = parse_xml;
  81 };