Hi Bart,
Haved a look at my HTTP client/server utilities:
http://espc22.murdoch.edu.au/~stewart/blackbox/index.html#dbu
Module DbuClient implements a simple HTTP 1.0 client. It uses a framework
that handles reading/writing network channels. Within the server this is
done as a background task. For simplicity, DbuClient.GetFile uses a
blocking loop, but with a little effort this could also be handled in the
background.
Module DbuChannels simplifies the management of network channels allowing
you to put/get files from a network stream. You simply need to implement a
Controller that decides what to do after each get/put operation has
completed. It handles buffering/read/write operations for you.
Hope this helps.
Cheers,
Stewart
"Wijck, Bart van" wrote:
>
> Hi,
>
> I am not experienced with BlackBox. I'm trying to create a simple BlackBox
> module which acts as a client and which requests a web page from a
> webserver. For this purpose we use a CommStream with protocol name
> 'CommTCP'. The thing with which I am struggling is the way to implement the
> ReadBytes for the response of the webserver.
> I understand the procedures are non-blocking.
> Using the module below, in procedure RequestPage I send a request for a
> webpage. I'm not sure how to capture/read the response.
> It looks as if procedure WriteBytes to the WebServer functions alright, but
> I need an event loop (or listener or event handler).
>
> MODULE WwebAgent;
>
> (* WwebAgent.Try *)
>
> IMPORT CommStreams, Out;
>
> CONST
> CONNECT_DONE = 0;
> CONNECT_INVALID_LOCAL = 2;
> CONNECT_INVALID_REMOTE = 3;
> CONNECT_NETWORK_DOWN = 4;
>
> TYPE
> STRING =
> ARRAY OF CHAR;
> STRING128 = ARRAY 129
> OF CHAR;
> STRING256 = ARRAY 266
> OF CHAR;
> STRING1024 = ARRAY 1025
> OF CHAR;
>
> VAR
> hostaddress : STRING128;
> sHTTP :
> CommStreams.Stream;
> connectstatus : INTEGER;
> pagestatus : BOOLEAN;
> (*
> ----------------------------------------------------------------------------
> --------- *)
> PROCEDURE StringToByte(IN s : ARRAY OF CHAR; OUT b : ARRAY OF BYTE);
> VAR
> i : INTEGER;
> BEGIN
> i := 0;
> WHILE (i < LEN(s$)) & (s[i] # 0X) DO
> b[i] := SHORT(SHORT(ORD(s[i])));
> INC(i);
> END;
> END StringToByte;
>
> (*
> ----------------------------------------------------------------------------
> --------- *)
> PROCEDURE ByteToString(IN b : ARRAY OF BYTE; bytecnt : INTEGER; OUT s: ARRAY
> OF CHAR);
> VAR
> i : INTEGER;
> BEGIN
> i := 0;
> WHILE (i < bytecnt) DO
> s[i] := CHR(b[i]);
> INC(i);
> END;
> s[i] := 0X;
> END ByteToString;
>
> (*
> ----------------------------------------------------------------------------
> --------- *)
> PROCEDURE Connect*(hostname : STRING; port : STRING): INTEGER;
> VAR
> res : INTEGER;
> BEGIN
> res := 0;
>
> Out.String('Connecting...');
> Out.Ln;
> hostaddress := hostname + ':' + port;
> CommStreams.NewStream ('CommTCP', '', hostaddress, sHTTP, res);
> Out.String('Connection status: ');
> Out.Int(res, 2);
> Out.Ln;
>
> RETURN res;
> END Connect;
>
> (*
> ----------------------------------------------------------------------------
> --------- *)
> PROCEDURE Close*;
> BEGIN
> sHTTP.Close;
> END Close;
>
> (*
> ----------------------------------------------------------------------------
> --------- *)
> PROCEDURE RequestPage*(url : STRING): BOOLEAN;
> VAR
> sRequest : STRING256;
> bRequest : ARRAY 513 OF BYTE;
> sReply : STRING1024;
> bReply : ARRAY 2049 OF BYTE;
> nrBytesWriten : INTEGER;
> nrBytesRead : INTEGER;
> BEGIN
> sRequest := '';
> sReply := '';
> nrBytesWriten := 0;
>
> IF ~sHTTP.IsConnected() THEN
> RETURN FALSE;
> END;
>
> Out.String('Request');
> Out.Ln;
>
> sRequest := 'GET ' + url + ' HTTP/1.1\nAccept: */*\nAccept-Language:
> nl\nAccept-Encoding: gzip\nUser-Agent: Mozilla/4.0 (compatible; MSIE 4.01;
> Windows 95)\n'+ hostaddress;
> StringToByte(sRequest, bRequest);
>
> sHTTP.WriteBytes(bRequest, 0, LEN(sRequest$), nrBytesWriten);
> Out.String('Send ');
> Out.Int(nrBytesWriten, 2);
> Out.String(' bytes');
> Out.Ln;
>
> sHTTP.ReadBytes(bReply, 0, 1024, nrBytesRead);
> ByteToString(bReply, nrBytesRead, sReply);
> Out.String('Reply: "' + sReply + '" (');
> Out.Int(nrBytesRead, 2);
> Out.String(' bytes).');
> Out.Ln;
>
> RETURN TRUE;
> END RequestPage;
>
> (*
> ----------------------------------------------------------------------------
> --------- *)
> PROCEDURE Try*;
> BEGIN
> connectstatus := Connect('127.0.0.1', '80');
> pagestatus := RequestPage('http://127.0.0.1/mercurius/logon.htm');
> Close();
> END Try;
>
> (*
> ----------------------------------------------------------------------------
> --------- *)
> BEGIN
> END WwebAgent.
>
> Regards,
>
> > ____________________________________
> > Bart van Wijck
> > Senior Business Development Consultant
> > Compuware BV
> > Telefoon: 020 311 88 57
> > Fax : 020 311 88 01
> > Mobiel : 06 54 35 23 76
> >
> >
> --------------------------------------------
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Received on Fri May 18 2001 - 23:27:55 UTC