Very slow throughput using sockets

[Ferreira Maurizio-2]

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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[Vitor Santos Costa-2]

Hi Maurizio

I tried the experiment with an even larger file. YAP is really a bit
slow, but that is mostly the overhead of sending byte by byte, which
is very expensive. Otherwise, it just chugs along.

Which OS are you using?

Cheers

Vitor

On Wed, Apr 22, 2009 at 10:32 AM, Ferreira Maurizio
<maurizio.ferreira@...> wrote:

> 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.
>
> ------------------------------------------------------------------------------
> Stay on top of everything new and different, both inside and
> around Java (TM) technology - register by April 22, and save
> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
> 300 plus technical and hands-on sessions. Register today.
> Use priority code J9JMT32. http://p.sf.net/sfu/p
> _______________________________________________
> Yap-users mailing list
> Yap-users@...
> https://lists.sourceforge.net/lists/listinfo/yap-users
>

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[Chris Mungall-5]

A possibly naive question:

SWI-Prolog has an excellent http library that makes web application  
development a breeze. Given that SWI and Yap are working together to  
increase compatibility (yay!!) how hard would it be to reuse the SWI  
library in Yap?

On Apr 22, 2009, at 8:32 AM, Ferreira Maurizio wrote:

> 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.
>
> ------------------------------------------------------------------------------
> Stay on top of everything new and different, both inside and
> around Java (TM) technology - register by April 22, and save
> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
> 300 plus technical and hands-on sessions. Register today.
> Use priority code J9JMT32. http://p.sf.net/sfu/p
> _______________________________________________
> Yap-users mailing list
> Yap-users@...
> https://lists.sourceforge.net/lists/listinfo/yap-users
>

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