Synapse: Reading data timeout

[bpranoto]

Using synapse version 40.1 this code snippet fails to receive the string

Code: Pascal  [Select][+][-]

1. var
2.   FConn:TTCPBlockSocket
3.  
4. ....
5.       if FConn.CanRead(3000) then begin
6.         FileVersion:=FConn.RecvString(12000);
7.       end;
8.  
9.  

However, if I change the code to:

Code: Pascal  [Select][+][-]

1.       FileVersion:='';
2.       Start:=GetTickCount64;
3.  
4.       while FileVersion='' do begin
5.         if FConn.CanRead(0) then begin
6.           FileVersion:=FConn.RecvString(12000);
7.         end;
8.         if (GetTickCount64 - Start)>1000 then begin
9.           // timeout
10.           break;
11.         end;
12.       end;
13.       if FileVersion <>'' then begin
14.           ...
15.       end;
16.       .......
17.  

It successfully receives the string

I think in the first verson, FConn.CanRead(3000) will wait for 3000 miliseconds to check if the string arrive, while in the secod version it only wait for 1000 ms to check. My question is why the first version fails even though it waits longer?

[bpranoto]

It turns it is my fault.

On the server side, I use Indy and when I send message to the client, I add CRLF to the the message string like this:

Server

Code: Pascal  [Select][+][-]

1. // Indy
2. Self.FContext.Connection.IOHandler.WriteLn(FileVersion+#13#10);
3.  

The synapse client, reading the file version string message

Code: Pascal  [Select][+][-]

1.       if FConn.CanRead(3000) then begin
2.         FileVersion:=FConn.RecvString(12000);
3.       end;
4.  

it only fetch string, and the CRLF is still left in the buffer. when it retrieve the next message, it gets a CRLF which is an empty string.