util/httpstream.lua

   1
   2 local coroutine = coroutine;
   3 local tonumber = tonumber;
   4
   5 local deadroutine = coroutine.create(function() end);
   6 coroutine.resume(deadroutine);
   7
   8 module("httpstream")
   9
  10 local function parser(data, success_cb)
  11         local function readline()
  12                 if not data then coroutine.yield("Unexpected EOF"); end
  13                 local pos, line = (data:find("\r\n", nil, true));
  14                 if not pos then
  15                         local newdata = coroutine.yield();
  16                         if not newdata then data = nil; coroutine.yield("Unexpected EOF"); end
  17                         data = data..newdata;
  18                         return readline();
  19                 end
  20                 line, data = data:sub(1, pos-1), data:sub(pos+2);
  21                 return line;
  22         end
  23         local function readlength(n)
  24                 if not data then coroutine.yield("Unexpected EOF"); end
  25                 while #data < n do
  26                         local newdata = coroutine.yield();
  27                         if not newdata then data = nil; coroutine.yield("Unexpected EOF"); end
  28                         data = data..newdata;
  29                 end
  30                 local r = data:sub(1, n);
  31                 data = data:sub(n + 1);
  32                 return r;
  33         end
  34
  35         while true do
  36                 -- read status line
  37                 local status_line = readline();
  38                 local method, path, httpversion = status_line:match("^(%S+)%s+(%S+)%s+HTTP/(%S+)$");
  39                 if not method then coroutine.yield("invalid-status-line"); end
  40                 -- TODO parse url
  41
  42                 local headers = {}; -- read headers
  43                 while true do
  44                         local line = readline();
  45                         if line == "" then break; end -- headers done
  46                         local key, val = line:match("^([^%s:]+): *(.*)$");
  47                         if not key then coroutine.yield("invalid-header-line"); end -- TODO handle multi-line and invalid headers
  48                         key = key:lower();
  49                         headers[key] = headers[key] and headers[key]..","..val or val;
  50                 end
  51
  52                 -- read body
  53                 local len = tonumber(headers["content-length"]);
  54                 len = len or 0; -- TODO check for invalid len
  55                 local body = readlength(len);
  56
  57                 success_cb({
  58                         method = method;
  59                         path = path;
  60                         httpversion = httpversion;
  61                         headers = headers;
  62                         body = body;
  63                 });
  64         end
  65 end
  66
  67 function new(success_cb, error_cb)
  68         local co = coroutine.create(parser);
  69         return {
  70                 feed = function(self, data)
  71                         local success, result = coroutine.resume(co, data, success_cb);
  72                         if result then
  73                                 if result.method then
  74                                         success_cb(result);
  75                                 else -- error
  76                                         error_cb(result);
  77                                         co = deadroutine;
  78                                 end
  79                         end
  80                 end;
  81         };
  82 end
  83
  84 return _M;