luci-base: switch to lucihttp based POST data processing

Use the liblucihttp provided multipart and x-www-urlencoded body parsers
and drop the old Lua parsing code.

The C based data parsers are way faster than their old Lua counterparts
while producing less string garbage and more correct results.

While refactoring the luci.http.protocol code, also drop unused functions
and dead code, heavily reducing the module size.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

2 files changed, 167 insertions, 517 deletions

diff --git a/modules/luci-base/luasrc/http/protocol.lua b/modules/luci-base/luasrc/http/protocol.lua
index 096ae46f4..7bbc55637 100644
--- a/modules/luci-base/luasrc/http/protocol.lua
+++ b/modules/luci-base/luasrc/http/protocol.lua
@@ -1,12 +1,16 @@
--- Copyright 2008 Freifunk Leipzig / Jo-Philipp Wich <jow@openwrt.org>
+-- Copyright 2008-2018 Jo-Philipp Wich <jo@mein.io>
 -- Licensed to the public under the Apache License 2.0.
 
 -- This class contains several functions useful for http message- and content
 -- decoding and to retrive form data from raw http messages.
-module("luci.http.protocol", package.seeall)
 
-local ltn12 = require("luci.ltn12")
-local util = require("luci.util")
+local require, type, tonumber = require, type, tonumber
+local table, pairs, ipairs, pcall = table, pairs, ipairs, pcall
+
+module "luci.http.protocol"
+
+local ltn12 = require "luci.ltn12"
+local lhttp = require "lucihttp"
 
 HTTP_MAX_CONTENT      = 1024*8		-- 8 kB maximum content size
 
@@ -14,32 +18,25 @@ HTTP_MAX_CONTENT      = 1024*8		-- 8 kB maximum content size
 -- Simple parameters are stored as string values associated with the parameter
 -- name within the table. Parameters with multiple values are stored as array
 -- containing the corresponding values.
-function urldecode_params( url, tbl )
-
+function urldecode_params(url, tbl)
+	local parser, name
 	local params = tbl or { }
 
-	if url:find("?") then
-		url = url:gsub( "^.+%?([^?]+)", "%1" )
-	end
-
-	for pair in url:gmatch( "[^&;]+" ) do
-
-		-- find key and value
-		local key = util.urldecode( pair:match("^([^=]+)")     )
-		local val = util.urldecode( pair:match("^[^=]+=(.+)$") )
+	parser = lhttp.urlencoded_parser(function (what, buffer, length)
+		if what == parser.TUPLE then
+			name, value = nil, nil
+		elseif what == parser.NAME then
+			name = lhttp.urldecode(buffer)
+		elseif what == parser.VALUE and name then
+			params[name] = lhttp.urldecode(buffer) or ""
+		end
 
-		-- store
-		if type(key) == "string" and key:len() > 0 then
-			if type(val) ~= "string" then val = "" end
+		return true
+	end)
 
-			if not params[key] then
-				params[key] = val
-			elseif type(params[key]) ~= "table" then
-				params[key] = { params[key], val }
-			else
-				table.insert( params[key], val )
-			end
-		end
+	if parser then
+		parser:parse((url or ""):match("[^?]*$"))
+		parser:parse(nil)
 	end
 
 	return params
@@ -47,185 +44,37 @@ end
 
 -- separated by "&". Tables are encoded as parameters with multiple values by
 -- repeating the parameter name with each value.
-function urlencode_params( tbl )
-	local enc = ""
-
+function urlencode_params(tbl)
+	local k, v
+	local n, enc = 1, {}
 	for k, v in pairs(tbl) do
 		if type(v) == "table" then
+			local i, v2
 			for i, v2 in ipairs(v) do
-				enc = enc .. ( #enc > 0 and "&" or "" ) ..
-					util.urlencode(k) .. "=" .. util.urlencode(v2)
-			end
-		else
-			enc = enc .. ( #enc > 0 and "&" or "" ) ..
-				util.urlencode(k) .. "=" .. util.urlencode(v)
-		end
-	end
-
-	return enc
-end
-
--- (Internal function)
--- Initialize given parameter and coerce string into table when the parameter
--- already exists.
-local function __initval( tbl, key )
-	if tbl[key] == nil then
-		tbl[key] = ""
-	elseif type(tbl[key]) == "string" then
-		tbl[key] = { tbl[key], "" }
-	else
-		table.insert( tbl[key], "" )
-	end
-end
-
--- (Internal function)
--- Initialize given file parameter.
-local function __initfileval( tbl, key, filename, fd )
-	if tbl[key] == nil then
-		tbl[key] = { file=filename, fd=fd, name=key, "" }
-	else
-		table.insert( tbl[key], "" )
-	end
-end
-
--- (Internal function)
--- Append given data to given parameter, either by extending the string value
--- or by appending it to the last string in the parameter's value table.
-local function __appendval( tbl, key, chunk )
-	if type(tbl[key]) == "table" then
-		tbl[key][#tbl[key]] = tbl[key][#tbl[key]] .. chunk
-	else
-		tbl[key] = tbl[key] .. chunk
-	end
-end
-
--- (Internal function)
--- Finish the value of given parameter, either by transforming the string value
--- or - in the case of multi value parameters - the last element in the
--- associated values table.
-local function __finishval( tbl, key, handler )
-	if handler then
-		if type(tbl[key]) == "table" then
-			tbl[key][#tbl[key]] = handler( tbl[key][#tbl[key]] )
-		else
-			tbl[key] = handler( tbl[key] )
-		end
-	end
-end
-
-
--- Table of our process states
-local process_states = { }
-
--- Extract "magic", the first line of a http message.
--- Extracts the message type ("get", "post" or "response"), the requested uri
--- or the status code if the line descripes a http response.
-process_states['magic'] = function( msg, chunk, err )
-
-	if chunk ~= nil then
-		-- ignore empty lines before request
-		if #chunk == 0 then
-			return true, nil
-		end
-
-		-- Is it a request?
-		local method, uri, http_ver = chunk:match("^([A-Z]+) ([^ ]+) HTTP/([01]%.[019])$")
-
-		-- Yup, it is
-		if method then
-
-			msg.type           = "request"
-			msg.request_method = method:lower()
-			msg.request_uri    = uri
-			msg.http_version   = tonumber( http_ver )
-			msg.headers        = { }
+				if enc[1] then
+					enc[n] = "&"
+					n = n + 1
+				end
 
-			-- We're done, next state is header parsing
-			return true, function( chunk )
-				return process_states['headers']( msg, chunk )
+				enc[n+0] = lhttp.urlencode(k)
+				enc[n+1] = "="
+				enc[n+2] = lhttp.urlencode(v2)
+				n = n + 3
 			end
-
-		-- Is it a response?
 		else
-
-			local http_ver, code, message = chunk:match("^HTTP/([01]%.[019]) ([0-9]+) ([^\r\n]+)$")
-
-			-- Is a response
-			if code then
-
-				msg.type           = "response"
-				msg.status_code    = code
-				msg.status_message = message
-				msg.http_version   = tonumber( http_ver )
-				msg.headers        = { }
-
-				-- We're done, next state is header parsing
-				return true, function( chunk )
-					return process_states['headers']( msg, chunk )
-				end
+			if enc[1] then
+				enc[n] = "&"
+				n = n + 1
 			end
-		end
-	end
-
-	-- Can't handle it
-	return nil, "Invalid HTTP message magic"
-end
-
-
--- Extract headers from given string.
-process_states['headers'] = function( msg, chunk )
-
-	if chunk ~= nil then
-
-		-- Look for a valid header format
-		local hdr, val = chunk:match( "^([A-Za-z][A-Za-z0-9%-_]+): +(.+)$" )
-
-		if type(hdr) == "string" and hdr:len() > 0 and
-		   type(val) == "string" and val:len() > 0
-		then
-			msg.headers[hdr] = val
 
-			-- Valid header line, proceed
-			return true, nil
-
-		elseif #chunk == 0 then
-			-- Empty line, we won't accept data anymore
-			return false, nil
-		else
-			-- Junk data
-			return nil, "Invalid HTTP header received"
+			enc[n+0] = lhttp.urlencode(k)
+			enc[n+1] = "="
+			enc[n+2] = lhttp.urlencode(v)
+			n = n + 3
 		end
-	else
-		return nil, "Unexpected EOF"
 	end
-end
-
 
--- data line by line with the trailing \r\n stripped of.
-function header_source( sock )
-	return ltn12.source.simplify( function()
-
-		local chunk, err, part = sock:receive("*l")
-
-		-- Line too long
-		if chunk == nil then
-			if err ~= "timeout" then
-				return nil, part
-					and "Line exceeds maximum allowed length"
-					or  "Unexpected EOF"
-			else
-				return nil, err
-			end
-
-		-- Line ok
-		elseif chunk ~= nil then
-
-			-- Strip trailing CR
-			chunk = chunk:gsub("\r$","")
-
-			return chunk, nil
-		end
-	end )
+	return table.concat(enc, "")
 end
 
 -- Content-Type. Stores all extracted data associated with its parameter name
@@ -238,286 +87,125 @@ end
 --  o Table containing decoded (name, file) and raw (headers) mime header data
 --  o String value containing a chunk of the file data
 --  o Boolean which indicates wheather the current chunk is the last one (eof)
-function mimedecode_message_body( src, msg, filecb )
-
-	if msg and msg.env.CONTENT_TYPE then
-		msg.mime_boundary = msg.env.CONTENT_TYPE:match("^multipart/form%-data; boundary=(.+)$")
-	end
-
-	if not msg.mime_boundary then
-		return nil, "Invalid Content-Type found"
-	end
-
+function mimedecode_message_body(src, msg, file_cb)
+	local parser, header, field
+	local len, maxlen = 0, tonumber(msg.env.CONTENT_LENGTH or nil)
 
-	local tlen   = 0
-	local inhdr  = false
-	local field  = nil
-	local store  = nil
-	local lchunk = nil
+	parser, err = lhttp.multipart_parser(msg.env.CONTENT_TYPE, function (what, buffer, length)
+		if what == parser.PART_INIT then
+			field = { }
 
-	local function parse_headers( chunk, field )
+		elseif what == parser.HEADER_NAME then
+			header = buffer:lower()
 
-		local stat
-		repeat
-			chunk, stat = chunk:gsub(
-				"^([A-Z][A-Za-z0-9%-_]+): +([^\r\n]+)\r\n",
-				function(k,v)
-					field.headers[k] = v
-					return ""
-				end
-			)
-		until stat == 0
-
-		chunk, stat = chunk:gsub("^\r\n","")
-
-		-- End of headers
-		if stat > 0 then
-			if field.headers["Content-Disposition"] then
-				if field.headers["Content-Disposition"]:match("^form%-data; ") then
-					field.name = field.headers["Content-Disposition"]:match('name="(.-)"')
-					field.file = field.headers["Content-Disposition"]:match('filename="(.+)"$')
-				end
+		elseif what == parser.HEADER_VALUE and header then
+			if header:lower() == "content-disposition" and
+			   lhttp.header_attribute(buffer, nil) == "form-data"
+			then
+				field.name = lhttp.header_attribute(buffer, "name")
+				field.file = lhttp.header_attribute(buffer, "filename")
 			end
 
-			if not field.headers["Content-Type"] then
-				field.headers["Content-Type"] = "text/plain"
+			if field.headers then
+				field.headers[header] = buffer
+			else
+				field.headers = { [header] = buffer }
 			end
 
-			if field.name and field.file and filecb then
-				__initval( msg.params, field.name )
-				__appendval( msg.params, field.name, field.file )
-
-				store = filecb
-			elseif field.name and field.file then
-				local nxf = require "nixio"
-				local fd = nxf.mkstemp(field.name)
-				__initfileval ( msg.params, field.name, field.file, fd )
-				if fd then
-					store = function(hdr, buf, eof)
-						fd:write(buf)
-						if (eof) then
-							fd:seek(0, "set")
-						end
-					end
+		elseif what == parser.PART_BEGIN then
+			return not field.file
+
+		elseif what == parser.PART_DATA and field.name and length > 0 then
+			if field.file then
+				if file_cb then
+					file_cb(field, buffer, false)
+					msg.params[field.name] = msg.params[field.name] or field
 				else
-					store = function( hdr, buf, eof )
-						__appendval( msg.params, field.name, buf )
+					if not field.fd then
+						local ok, nx = pcall(require, "nixio")
+						field.fd = ok and nx.mkstemp(field.name)
+					end
+
+					if field.fd then
+						field.fd:write(buffer)
+						msg.params[field.name] = msg.params[field.name] or field
 					end
 				end
-			elseif field.name then
-				__initval( msg.params, field.name )
+			else
+				field.value = buffer
+			end
 
-				store = function( hdr, buf, eof )
-					__appendval( msg.params, field.name, buf )
+		elseif what == parser.PART_END and field.name then
+			if field.file and msg.params[field.name] then
+				if file_cb then
+					file_cb(field, "", true)
+				elseif field.fd then
+					field.fd:seek(0, "set")
 				end
 			else
-				store = nil
+				msg.params[field.name] = field.value or ""
 			end
 
-			return chunk, true
-		end
+			field = nil
 
-		return chunk, false
-	end
+		elseif what == parser.ERROR then
+			err = buffer
+		end
 
-	local function snk( chunk )
+		return true
+	end)
 
-		tlen = tlen + ( chunk and #chunk or 0 )
+	return ltn12.pump.all(src, function (chunk)
+		len = len + (chunk and #chunk or 0)
 
-		if msg.env.CONTENT_LENGTH and tlen > tonumber(msg.env.CONTENT_LENGTH) + 2 then
+		if maxlen and len > maxlen + 2 then
 			return nil, "Message body size exceeds Content-Length"
 		end
 
-		if chunk and not lchunk then
-			lchunk = "\r\n" .. chunk
-
-		elseif lchunk then
-			local data = lchunk .. ( chunk or "" )
-			local spos, epos, found
-
-			repeat
-				spos, epos = data:find( "\r\n--" .. msg.mime_boundary .. "\r\n", 1, true )
-
-				if not spos then
-					spos, epos = data:find( "\r\n--" .. msg.mime_boundary .. "--\r\n", 1, true )
-				end
-
-
-				if spos then
-					local predata = data:sub( 1, spos - 1 )
-
-					if inhdr then
-						predata, eof = parse_headers( predata, field )
-
-						if not eof then
-							return nil, "Invalid MIME section header"
-						elseif not field.name then
-							return nil, "Invalid Content-Disposition header"
-						end
-					end
-
-					if store then
-						store( field, predata, true )
-					end
-
-
-					field = { headers = { } }
-					found = found or true
-
-					data, eof = parse_headers( data:sub( epos + 1, #data ), field )
-					inhdr = not eof
-				end
-			until not spos
-
-			if found then
-				-- We found at least some boundary. Save
-				-- the unparsed remaining data for the
-				-- next chunk.
-				lchunk, data = data, nil
-			else
-				-- There was a complete chunk without a boundary. Parse it as headers or
-				-- append it as data, depending on our current state.
-				if inhdr then
-					lchunk, eof = parse_headers( data, field )
-					inhdr = not eof
-				else
-					-- We're inside data, so append the data. Note that we only append
-					-- lchunk, not all of data, since there is a chance that chunk
-					-- contains half a boundary. Assuming that each chunk is at least the
-					-- boundary in size, this should prevent problems
-					store( field, lchunk, false )
-					lchunk, chunk = chunk, nil
-				end
-			end
+		if not parser or not parser:parse(chunk) then
+			return nil, err
 		end
 
 		return true
-	end
-
-	return ltn12.pump.all( src, snk )
+	end)
 end
 
 -- Content-Type. Stores all extracted data associated with its parameter name
 -- in the params table within the given message object. Multiple parameter
 -- values are stored as tables, ordinary ones as strings.
-function urldecode_message_body( src, msg )
-
-	local tlen   = 0
-	local lchunk = nil
-
-	local function snk( chunk )
-
-		tlen = tlen + ( chunk and #chunk or 0 )
-
-		if msg.env.CONTENT_LENGTH and tlen > tonumber(msg.env.CONTENT_LENGTH) + 2 then
-			return nil, "Message body size exceeds Content-Length"
-		elseif tlen > HTTP_MAX_CONTENT then
-			return nil, "Message body size exceeds maximum allowed length"
-		end
-
-		if not lchunk and chunk then
-			lchunk = chunk
-
-		elseif lchunk then
-			local data = lchunk .. ( chunk or "&" )
-			local spos, epos
-
-			repeat
-				spos, epos = data:find("^.-[;&]")
-
-				if spos then
-					local pair = data:sub( spos, epos - 1 )
-					local key  = pair:match("^(.-)=")
-					local val  = pair:match("=([^%s]*)%s*$")
-
-					if key and #key > 0 then
-						__initval( msg.params, key )
-						__appendval( msg.params, key, val )
-						__finishval( msg.params, key, urldecode )
-					end
-
-					data = data:sub( epos + 1, #data )
-				end
-			until not spos
-
-			lchunk = data
+function urldecode_message_body(src, msg)
+	local err, name, value, parser
+	local len, maxlen = 0, tonumber(msg.env.CONTENT_LENGTH or nil)
+
+	parser = lhttp.urlencoded_parser(function (what, buffer, length)
+		if what == parser.TUPLE then
+			name, value = nil, nil
+		elseif what == parser.NAME then
+			name = lhttp.urldecode(buffer)
+		elseif what == parser.VALUE and name then
+			msg.params[name] = lhttp.urldecode(buffer) or ""
+		elseif what == parser.ERROR then
+			err = buffer
 		end
 
 		return true
-	end
-
-	return ltn12.pump.all( src, snk )
-end
+	end)
 
--- version, message headers and resulting CGI environment variables from the
--- given ltn12 source.
-function parse_message_header( src )
+	return ltn12.pump.all(src, function (chunk)
+		len = len + (chunk and #chunk or 0)
 
-	local ok   = true
-	local msg  = { }
-
-	local sink = ltn12.sink.simplify(
-		function( chunk )
-			return process_states['magic']( msg, chunk )
+		if maxlen and len > maxlen + 2 then
+			return nil, "Message body size exceeds Content-Length"
+		elseif len > HTTP_MAX_CONTENT then
+			return nil, "Message body size exceeds maximum allowed length"
 		end
-	)
-
-	-- Pump input data...
-	while ok do
-
-		-- get data
-		ok, err = ltn12.pump.step( src, sink )
 
-		-- error
-		if not ok and err then
+		if not parser or not parser:parse(chunk) then
 			return nil, err
-
-		-- eof
-		elseif not ok then
-
-			-- Process get parameters
-			if ( msg.request_method == "get" or msg.request_method == "post" ) and
-			   msg.request_uri:match("?")
-			then
-				msg.params = urldecode_params( msg.request_uri )
-			else
-				msg.params = { }
-			end
-
-			-- Populate common environment variables
-			msg.env = {
-				CONTENT_LENGTH    = msg.headers['Content-Length'];
-				CONTENT_TYPE      = msg.headers['Content-Type'] or msg.headers['Content-type'];
-				REQUEST_METHOD    = msg.request_method:upper();
-				REQUEST_URI       = msg.request_uri;
-				SCRIPT_NAME       = msg.request_uri:gsub("?.+$","");
-				SCRIPT_FILENAME   = "";		-- XXX implement me
-				SERVER_PROTOCOL   = "HTTP/" .. string.format("%.1f", msg.http_version);
-				QUERY_STRING      = msg.request_uri:match("?")
-					and msg.request_uri:gsub("^.+?","") or ""
-			}
-
-			-- Populate HTTP_* environment variables
-			for i, hdr in ipairs( {
-				'Accept',
-				'Accept-Charset',
-				'Accept-Encoding',
-				'Accept-Language',
-				'Connection',
-				'Cookie',
-				'Host',
-				'Referer',
-				'User-Agent',
-			} ) do
-				local var = 'HTTP_' .. hdr:upper():gsub("%-","_")
-				local val = msg.headers[hdr]
-
-				msg.env[var] = val
-			end
 		end
-	end
 
-	return msg
+		return true
+	end)
 end
 
 -- This function will examine the Content-Type within the given message object
@@ -526,17 +214,18 @@ end
 -- mime types are supported. If the encountered content encoding can't be
 -- handled then the whole message body will be stored unaltered as "content"
 -- property within the given message object.
-function parse_message_body( src, msg, filecb )
+function parse_message_body(src, msg, filecb)
+	local ctype = lhttp.header_attribute(msg.env.CONTENT_TYPE, nil)
+
 	-- Is it multipart/mime ?
-	if msg.env.REQUEST_METHOD == "POST" and msg.env.CONTENT_TYPE and
-	   msg.env.CONTENT_TYPE:match("^multipart/form%-data")
+	if msg.env.REQUEST_METHOD == "POST" and
+	   ctype == "multipart/form-data"
 	then
-
 		return mimedecode_message_body( src, msg, filecb )
 
 	-- Is it application/x-www-form-urlencoded ?
-	elseif msg.env.REQUEST_METHOD == "POST" and msg.env.CONTENT_TYPE and
-	       msg.env.CONTENT_TYPE:match("^application/x%-www%-form%-urlencoded")
+	elseif msg.env.REQUEST_METHOD == "POST" and
+	       ctype == "application/x-www-form-urlencoded"
 	then
 		return urldecode_message_body( src, msg, filecb )
 
@@ -594,21 +283,3 @@ function parse_message_body( src, msg, filecb )
 		return true
 	end
 end
-
-statusmsg = {
-	[200] = "OK",
-	[206] = "Partial Content",
-	[301] = "Moved Permanently",
-	[302] = "Found",
-	[304] = "Not Modified",
-	[400] = "Bad Request",
-	[403] = "Forbidden",
-	[404] = "Not Found",
-	[405] = "Method Not Allowed",
-	[408] = "Request Time-out",
-	[411] = "Length Required",
-	[412] = "Precondition Failed",
-	[416] = "Requested range not satisfiable",
-	[500] = "Internal Server Error",
-	[503] = "Server Unavailable",
-}
diff --git a/modules/luci-base/luasrc/http/protocol.luadoc b/modules/luci-base/luasrc/http/protocol.luadoc
index cf3d5b2d2..0c9ff6fa4 100644
--- a/modules/luci-base/luasrc/http/protocol.luadoc
+++ b/modules/luci-base/luasrc/http/protocol.luadoc
@@ -8,47 +8,41 @@ module "luci.http.protocol"
 
 ---[[
 Extract and split urlencoded data pairs, separated bei either "&" or ";"
-
 from given url or string. Returns a table with urldecoded values.
+
 Simple parameters are stored as string values associated with the parameter
 name within the table. Parameters with multiple values are stored as array
 containing the corresponding values.
-@class function
-@name urldecode_params
-@param url	The url or string which contains x-www-urlencoded form data
-@param tbl	Use the given table for storing values (optional)
-@return		Table containing the urldecoded parameters
+
+@class 			function
+@name 			urldecode_params
+@param url		The url or string which contains x-www-urlencoded form data
+@param tbl		Use the given table for storing values (optional)
+@return			Table containing the urldecoded parameters
 @see			urlencode_params
 ]]
 
 ---[[
 Encode each key-value-pair in given table to x-www-urlencoded format,
+separated by "&".
 
-separated by "&". Tables are encoded as parameters with multiple values by
-repeating the parameter name with each value.
-@class function
-@name urlencode_params
-@param tbl	Table with the values
-@return		String containing encoded values
-@see			urldecode_params
-]]
-
----[[
-Creates a ltn12 source from the given socket. The source will return it's
+Tables are encoded as parameters with multiple values by repeating the
+parameter name with each value.
 
-data line by line with the trailing \r\n stripped of.
-@class function
-@name header_source
-@param sock	Readable network socket
-@return		Ltn12 source function
+@class 			function
+@name 			urlencode_params
+@param tbl		Table with the values
+@return			String containing encoded values
+@see			urldecode_params
 ]]
 
 ---[[
-Decode a mime encoded http message body with multipart/form-data
+Decode a mime encoded http message body with multipart/form-data Content-Type.
 
-Content-Type. Stores all extracted data associated with its parameter name
+Stores all extracted data associated with its parameter name
 in the params table within the given message object. Multiple parameter
 values are stored as tables, ordinary ones as strings.
+
 If an optional file callback function is given then it is feeded with the
 file contents chunk by chunk and only the extracted file name is stored
 within the params table. The callback function will be called subsequently
@@ -56,65 +50,50 @@ with three arguments:
  o Table containing decoded (name, file) and raw (headers) mime header data
  o String value containing a chunk of the file data
  o Boolean which indicates wheather the current chunk is the last one (eof)
-@class function
-@name mimedecode_message_body
+
+@class 			function
+@name 			mimedecode_message_body
 @param src		Ltn12 source function
 @param msg		HTTP message object
 @param filecb	File callback function (optional)
 @return			Value indicating successful operation (not nil means "ok")
 @return			String containing the error if unsuccessful
-@see				parse_message_header
+@see			parse_message_header
 ]]
 
 ---[[
 Decode an urlencoded http message body with application/x-www-urlencoded
+Content-Type.
 
-Content-Type. Stores all extracted data associated with its parameter name
-in the params table within the given message object. Multiple parameter
-values are stored as tables, ordinary ones as strings.
-@class function
-@name urldecode_message_body
-@param src	Ltn12 source function
-@param msg	HTTP message object
-@return		Value indicating successful operation (not nil means "ok")
-@return		String containing the error if unsuccessful
-@see			parse_message_header
-]]
+Stores all extracted data associated with its parameter name in the params
+table within the given message object. Multiple parameter values are stored
+as tables, ordinary ones as strings.
 
----[[
-Try to extract an http message header including information like protocol
-
-version, message headers and resulting CGI environment variables from the
-given ltn12 source.
-@class function
-@name parse_message_header
-@param src	Ltn12 source function
-@return		HTTP message object
-@see			parse_message_body
+@class 			function
+@name 			urldecode_message_body
+@param src		Ltn12 source function
+@param msg		HTTP message object
+@return			Value indicating successful operation (not nil means "ok")
+@return			String containing the error if unsuccessful
+@see			parse_message_header
 ]]
 
 ---[[
 Try to extract and decode a http message body from the given ltn12 source.
-
 This function will examine the Content-Type within the given message object
 to select the appropriate content decoder.
+
 Currently the application/x-www-urlencoded and application/form-data
 mime types are supported. If the encountered content encoding can't be
 handled then the whole message body will be stored unaltered as "content"
 property within the given message object.
-@class function
-@name parse_message_body
+
+@class 			function
+@name 			parse_message_body
 @param src		Ltn12 source function
 @param msg		HTTP message object
 @param filecb	File data callback (optional, see mimedecode_message_body())
 @return			Value indicating successful operation (not nil means "ok")
 @return			String containing the error if unsuccessful
-@see				parse_message_header
-]]
-
----[[
-Table containing human readable messages for several http status codes.
-
-@class table
+@see			parse_message_header
 ]]
-