> since 3 weeks I'm trying to send a file with TWSocket and > TWSocketServer components.. > my idea was to send records like: > > pFileBuf = ^TFileBuf; > TFileBuf = packed record > ID : Integer; > bufSize : Integer; > buf: array[0..1023] of Byte; > end;
That's OK except you should put the bufsize in front of the record. > so I tried to receive these records in a pointer buffer and then to > process the buffer like the ICS FAQ for TWSocket "Receiving high speed > data > <http://users.pandora.be/sonal.nv/ics/faq/TWSocket.html#Receivinghighspeeddata228>" > and write every single record to disk in ProcessData procedure > > sometimes the first record was send correctly but the other records were > currupt.. You probably forgot that TCP stream doesn't preserve boundaries. Even if you send your record in one chunk, you may receive. You _will_ receive it either split in several packets, or several small would be merged in a larger packet. Packet boundaries will not likely to match record boundaries. You must take care of that behaviour when receiving data. > my WSocket1DataSent looks like this: > .. > var > fbuf : TFileBuf; > begin > if sendnow then begin > if not Eof(f) then begin > BlockRead(f,FBuf.buf,SizeOf(FBuf.buf),numread); > FBuf.bufSize:=numread; > FBuf.ID:=2; > WSocket1.Send(@fbuf, SizeOf(tfilebuf)); > end; > end; //sendnow > end;//proc This will work but has a side effect which may be undersirable. Because TWSocket is async, calling Send is not blocking, your data will be put into a buffer for sending in the background. Reading the file will be much much faster than sending on the network. The net effect is that you'll have almost all data into the file stored in the buffer, taking a lot of valuable RAM space. To avoid this, do not use a loop with any asynchronous, event driven component. Use events ! When you send data, you'll get an OnDataSent event when your data has been passed to winsock (which has also his own buffer). From that event handler read the next record and send it. No loop. -- Contribute to the SSL Effort. Visit http://www.overbyte.be/eng/ssl.html -- [EMAIL PROTECTED] http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
