Re: [fpc-pascal] libevent for socket

[Bo Berglund]

On Sun, 17 Jan 2016 16:34:45 -0300, silvioprog
 wrote:

>On Tue, Jan 5, 2016 at 12:15 PM, Xiangrong Fang  wrote:
>
>> Hi All,
>>
>> Could anyone help me with some samples of writing socket program with
>> libevent, or is there any adapter/wrapper already exists for freepascal?
>>
>
>I used libevent in a C project, but you can use it easily with Pascal (FPC
>and/or Delphi). For example, I did this small draft [1] that compiles in
>Free Pascal (it is just a helloworld fast HTTP server), using the libevent
>2.0.5:
>

Is this a purely Windows thing or is it portable to all environments
supported by FreePascal, like Linux on ARM etc?
There seems to be conditionals for MSWINDOWS but nothing else


-- 
Bo Berglund
Developer in Sweden

___
fpc-pascal maillist  -  fpc-pascal@lists.freepascal.org
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal

Re: [fpc-pascal] libevent for socket

[Michael Van Canneyt]

On Thu, 21 Jan 2016, Bo Berglund wrote:


On Sun, 17 Jan 2016 16:34:45 -0300, silvioprog
 wrote:


On Tue, Jan 5, 2016 at 12:15 PM, Xiangrong Fang  wrote:


Hi All,

Could anyone help me with some samples of writing socket program with
libevent, or is there any adapter/wrapper already exists for freepascal?



I used libevent in a C project, but you can use it easily with Pascal (FPC
and/or Delphi). For example, I did this small draft [1] that compiles in
Free Pascal (it is just a helloworld fast HTTP server), using the libevent
2.0.5:



Is this a purely Windows thing or is it portable to all environments
supported by FreePascal, like Linux on ARM etc?
There seems to be conditionals for MSWINDOWS but nothing else


It works on all unix (including raspberry) platforms as well.

Michael.
___
fpc-pascal maillist  -  fpc-pascal@lists.freepascal.org
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal

Re: [fpc-pascal] libevent for socket

[silvioprog]

On Tue, Jan 5, 2016 at 12:15 PM, Xiangrong Fang  wrote:

> Hi All,
>
> Could anyone help me with some samples of writing socket program with
> libevent, or is there any adapter/wrapper already exists for freepascal?
>

I used libevent in a C project, but you can use it easily with Pascal (FPC
and/or Delphi). For example, I did this small draft [1] that compiles in
Free Pascal (it is just a helloworld fast HTTP server), using the libevent
2.0.5:

=== begin code ===

program helloworld;

{$mode objfpc}{$H+}

uses
{$IFDEF MSWINDOWS}
  WinSock2,
{$ENDIF}
  ctypes;

const
  EV_LIB_NAME = {$IFDEF MSWINDOWS}'libevent-2-0-5'{$ELSE}'event'{$ENDIF};

{$IFDEF FPC}
  {$PACKRECORDS C}
{$ENDIF}

const
  HTTP_OK = 200;

type
  pcchar = PAnsiChar;

  evbuffer = packed record
  end;
  Pevbuffer = ^evbuffer;

  event_base = packed record
  end;
  Pevent_base = ^event_base;

  evhttp = packed record
  end;
  Pevhttp = ^evhttp;

  evhttp_request = packed record
  end;
  Pevhttp_request = ^evhttp_request;

  evkeyvalq = packed record
  end;
  Pevkeyvalq = ^evkeyvalq;

  evhttp_set_gencb_cb = procedure(p1: Pevhttp_request; p2: Pointer); cdecl;

  function evbuffer_add_printf(buf: Pevbuffer; fmt: pcchar): cint; cdecl;
varargs; external EV_LIB_NAME name 'evbuffer_add_printf';
  function event_init: pevent_base; cdecl; external EV_LIB_NAME name
'event_init';
  function event_dispatch: cint; cdecl; external EV_LIB_NAME name
'event_dispatch';
  function evhttp_start(address: pcchar;  port: cshort): pevhttp; cdecl;
external EV_LIB_NAME name 'evhttp_start';
  function evbuffer_new: Pevbuffer; cdecl; external EV_LIB_NAME name
'evbuffer_new';
  procedure evhttp_set_gencb(http: Pevhttp; cb: evhttp_set_gencb_cb; arg:
Pointer); cdecl; external EV_LIB_NAME name 'evhttp_set_gencb';
  function evhttp_add_header(headers: Pevkeyvalq; key: pcchar; value:
pcchar): cint; cdecl; external EV_LIB_NAME name 'evhttp_add_header';
  function evhttp_request_get_output_headers(req: Pevhttp_request):
Pevkeyvalq; cdecl; external EV_LIB_NAME name
'evhttp_request_get_output_headers';
  procedure evhttp_send_reply_start(req: Pevhttp_request; code: cint;
reason: pcchar); cdecl; external EV_LIB_NAME name 'evhttp_send_reply_start';
  procedure evhttp_send_reply_chunk(req: Pevhttp_request; databuf:
Pevbuffer); cdecl; external EV_LIB_NAME name 'evhttp_send_reply_chunk';
  procedure evhttp_send_reply_end(req: Pevhttp_request); cdecl; external
EV_LIB_NAME name 'evhttp_send_reply_end';
  procedure evbuffer_free(buf: Pevbuffer); cdecl; external EV_LIB_NAME name
'evbuffer_free';

  procedure generic_request_handler(req: Pevhttp_request; arg: Pointer);
cdecl;
  var
returnbuffer: Pevbuffer;
  begin
returnbuffer := evbuffer_new;
evhttp_add_header(evhttp_request_get_output_headers(req),
'Content-Type', 'text/html');
evhttp_add_header(evhttp_request_get_output_headers(req), 'Connection',
'keep-alive');
evbuffer_add_printf(returnbuffer, 'Hello
worldHello world');
evhttp_send_reply_start(req, HTTP_OK, 'OK');
// Chuncked reply
evhttp_send_reply_chunk(req, returnbuffer);
evhttp_send_reply_end(req);
evbuffer_free(returnbuffer);
  end;

var
  http_port: cshort = 8080;
  http_addr: pcchar = '0.0.0.0';
  http_server: Pevhttp = nil;
{$IFDEF MSWINDOWS}
  wsa_data: WSAData;
{$ENDIF}
begin
{$IFDEF MSWINDOWS}
  WSAStartup($0201, wsa_data);
{$ENDIF}
  event_init;
  http_server := evhttp_start(http_addr, http_port);
  evhttp_set_gencb(http_server, @generic_request_handler, nil); // Callback
on event
  WriteLn('Server started on port ', http_port);
  WriteLn('Press [ENTER] to exit ...');
  event_dispatch;
end.

=== end code ===

-- 
Silvio Clécio
___
fpc-pascal maillist  -  fpc-pascal@lists.freepascal.org
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal