%% httpd.erl - MicroHttpd 
-module(httpd). 
-author("ninhenry@gmail.com"). 
 
-export([start/0,start/1,start/2,process/2]). 
-import(regexp,[split/2]). 
 
-define(defPort,8888). 
-define(docRoot,"public"). 
 
start() -> start(?defPort,?docRoot). 
start(Port) -> start(Port,?docRoot).  
start(Port,DocRoot) -> 
 case gen_tcp:listen(Port, [binary,{packet, 0},{active, false}]) of 
  {ok, LSock} -> server_loop(LSock,DocRoot); 
   {error, Reason}  -> exit({Port,Reason}) 
 end. 
 
%% main server loop - wait for next connection, spawn child to process it 
server_loop(LSock,DocRoot) -> 
 case gen_tcp:accept(LSock) of 
  {ok, Sock} -> 
   spawn(?MODULE,process,[Sock,DocRoot]), 
   server_loop(LSock,DocRoot); 
  {error, Reason} -> 
   exit({accept,Reason}) 
 end. 
 
%% process current connection 
process(Sock,DocRoot) -> 
 Req = do_recv(Sock), 
 {ok,[Cmd|[Name|[Vers|_]]]} = split(Req,"[ \r\n]"), 
 FileName = DocRoot ++ Name, 
 LogReq = Cmd ++ " " ++ Name ++ " " ++ Vers, 
 Resp = case file:read_file(FileName) of 
  {ok, Data} -> 
   io:format("~p ~p ok~n",[LogReq,FileName]), 
   Data; 
  {error, Reason} -> 
   io:format("~p ~p failed ~p~n",[LogReq,FileName,Reason]), 
   error_response(LogReq,file:format_error(Reason)) 
  end,  
 do_send(Sock,Resp), 
 gen_tcp:close(Sock). 
 
%% construct HTML for failure message 
error_response(LogReq,Reason) -> 
 "html>head>title>Request Failed/title>/head>body>\n" ++ 
 "h1>Request Failed/h1>\n" ++ "Your request to " ++ LogReq ++ 
 " failed due to: " ++ Reason ++ "\n/body>/html>\n". 
 
%% send a line of text to the socket 
do_send(Sock,Msg) -> 
 case gen_tcp:send(Sock, Msg) of 
  ok -> ok; 
   {error, Reason} -> exit(Reason) 
 end. 
 
%% receive data from the socket 
do_recv(Sock) -> 
 case gen_tcp:recv(Sock, 0) of 
  {ok, Bin} -> binary_to_list(Bin); 
   {error, closed} -> exit(closed); 
   {error, Reason} -> exit(Reason) 
 end