Re: Very slow throughput using sockets

> I'm tyring to develop a (very) basic web server, using yap-prolog  
> but I
> experience a very slow throughput using the socket functions. The
> following program is just an excerpt of a bigger program, but
> it experiences the same problem.
> It sends a small file (test.txt) about 40kb in size, regardless of the
> input query.
>
> To try it just create a text file called test.txt, about 40/50 kb in
> size, load the program in yap, open a browser and query http://127.0.0.1
>
> I've tried it with different files, both text files than images (gif  
> and
> png). In the console window you can see two messages, 'before' and
> 'after', issued just before and after the sending of the file.
> You will notice the delay.
> Then try with a bigger file (200/300 kb).
> The delay becomes intollerable.
>
>
> Any suggestion?
>
> Regards
> Maurizio.
>
> %----------------------------------------------------------------------%
> %                            global  
> include                            %
> %----------------------------------------------------------------------%
>
> :- use_module(library(system)).
> :- use_module(library(lists)).
> :- use_module(library(charsio)).
> :- use_module(library(readutil)).
> :- set_prolog_flag(unknown,error).
>
> %----------------------------------------------------------------------%
> %                            i/o    
> handling                            %
> %----------------------------------------------------------------------%
>
>
>
> send_message(Sout,Rcode,Contype,Message):-
>   send_message_header(Sout,Rcode,Contype,"",Message).
>
> send_message_header(Sout,Rcode,Contype,Header,Message):-
>   put_bytes("HTTP/1.0 ",Sout), put_bytes(Rcode,Sout),
> put_bytes("\r\n",Sout),
>   put_bytes("Content-Type: ",Sout), put_bytes(Contype,Sout),
> put_bytes("\r\n",Sout),
>   put_bytes(Header,Sout),
>   code_len(Message,Size),
>   put_bytes("Content-Length: ",Sout),  put_bytes(Size,Sout),
> put_bytes("\r\n\r\n",Sout),
>   put_bytes(Message,Sout).
>
> code_len(Message,Len):-
>   length(Message,Size),
>   number_codes(Size,Len).
>
> put_bytes([],_Sout).
> put_bytes([C|R],Sout):-  put_byte(Sout,C), put_bytes(R,Sout).
>
>
> read_in_list(Name,List):-
>    open(Name,read,S,[type(binary)]),
>    read_stream_to_codes(S,List),
>    close(S).
>
> send_file(Filename,Type,Sout):-
>  read_in_list(Filename,L),
>  write(before),nl,
>  send_message(Sout,"200 OK",Type,L),
>  write(after),nl.
>
>
>
> %----------------------------------------------------------------------%
> %                            
> main                                      %
> %----------------------------------------------------------------------%
>
> :- initialization(go).
>
>
> go:-
>    socket('AF_INET',Sock),
>    socket_bind(Sock,'AF_INET'(_,80)),
>    socket_listen(Sock,5),
>    main_loop(Sock).
>
> main_loop(Sock) :-
>    repeat,
>    socket_accept(Sock,Sin),
>    send_file('test.txt',"text/plain",Sin),
>    flush_output(Sin),
>    close(Sin),
>    fail.
>
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