%%
%% %CopyrightBegin%
%% 
%% Copyright Ericsson AB 2001-2010. All Rights Reserved.
%% 
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%% 
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%% 
%% %CopyrightEnd%
%%
%%
-module(mod_trace).

-export([do/1]).

-include("httpd.hrl").


do(Info) ->
    %%?vtrace("do",[]),
    case Info#mod.method of
	"TRACE" ->
	    case response_generated(Info) of
		false->
		    generate_trace_response(Info);
	        true->
		    {proceed,Info#mod.data}
	    end;
	_ ->
	    {proceed,Info#mod.data}
    end.


%%---------------------------------------------------------------------
%%Generate the trace response the trace response consists of a 
%%http-header and the body will be the request.
%5----------------------------------------------------------------------

generate_trace_response(Info)->
    RequestHead=Info#mod.parsed_header,
    Body=generate_trace_response_body(RequestHead),
    Len = length(Info#mod.request_line ++ Body),
    Response=["HTTP/1.1 200 OK\r\n",
	      "Content-Type:message/http\r\n",
	      "Content-Length:",integer_to_list(Len),"\r\n\r\n",
	      Info#mod.request_line,Body],
    httpd_socket:deliver(Info#mod.socket_type,Info#mod.socket,Response),
    {proceed,[{response,{already_sent,200,Len}}|Info#mod.data]}.

generate_trace_response_body(Parsed_header)->
    generate_trace_response_body(Parsed_header,[]).

generate_trace_response_body([],Head)->
    lists:flatten(Head);
generate_trace_response_body([{[],[]}|Rest],Head) ->
    generate_trace_response_body(Rest,Head);
generate_trace_response_body([{Field,Value}|Rest],Head) ->
    generate_trace_response_body(Rest,[Field ++ ":" ++ Value ++ "\r\n"|Head]).



%%----------------------------------------------------------------------
%%Function that controls whether a response is generated or not
%%----------------------------------------------------------------------
response_generated(Info)->
    case proplists:get_value(status, Info#mod.data) of
	%% A status code has been generated!
	{_StatusCode,_PhraseArgs,_Reason}->
	    true;
	%%No status code control repsonsxe
	undefined ->
	    case proplists:get_value(response, Info#mod.data) of
		%% No response has been generated!
		undefined ->
		    false;
		%% A response has been generated or sent!
		_Response ->
		    true
	    end
    end.