Connection is not closed

[ClarkVent]

I have the following piece of code which is called once every minute or so (inside a timer event):

    client.New1
client.Connect( RemoteHostIP, RemoteHostPort )
BinaryFile.New1( client.GetStream, True )
BinaryFile.WriteString( SendString )
client.Close

This sends the contents of "SendString" (which is only about 80 bytes in size) to the server at "RemoteHostIP:RemoteHostPort" just fine. However, client.Close doesn't actually close the connection.

So if I run the program for about 10 minutes, it will have opened 10 connections which are only closed when I actually exit the program.

Why?

[agraham]

The Network client is .NET TcpClient. From "Network Programming for the Microsoft .NET Framework" P179.

TcpClient does not offer a method to shut down the connection, but the close method should be called when the connection is done to release the underlying network resources.

Also The TcpClient Close method does not close the underlying TCP connection

You could try this and see if it works. Obj1 is a Door library Object

Client.New1
Obj1.New1(False)
  ...
Client.Connect(....)
  ...
Obj1.FromLibrary("Main.Client", "m_DataStream", B4PObject(2))
Obj1.RunMethod("Close")
Client.Close

[ClarkVent]

I'm getting a NullReferenceException error on this line:

Obj1.FromLibrary("Main.Client", "m_DataStream", B4PObject(2))

[agraham]

Originally Posted by ClarkVent

I'm getting a NullReferenceException error on this line:

Yes you will, I was looking at the wrong object

Try this - we'll get there in the end!

Client.New1
Obj1.New1(False)
  ...
Client.Connect(....)
  ...
Obj1.Value = Client.GetStream
Obj1.RunMethod2("Close", 0, "System.Int32"))
Client.Close

[ClarkVent]

This didn't work:

Obj1.RunMethod2("Close", 0, "System.Int32"))

This of course did:

Obj1.RunMethod("Close")

That closed the connection perfectly! Thanks for your help!

[ClarkVent]

On another note (and slightly off topic), this code:

client.New1
client.Connect( RemoteHostIP, RemoteHostPort )
BinaryFile.New1( client.GetStream, True )
BinaryFile.WriteString( "Test" )
client.Close

doesn't actually send "Test" to the remote host, but "<some character>Test". It always sends some (seemingly) random character first. Is this a bug?

[agraham]

Originally Posted by ClarkVent

It always sends some (seemingly) random character first. Is this a bug?

No, it's a length indicator, from the BinaryFile help "WriteString ... Writes a string prefixed with its length to the file." Binary file can mix types in the stream so for those that don't have a fixed length like a string a count indicator is needed so that the end of the string can be determined. This is fine when you have a BinaryFile at each end but for sending arbitrary data to a server the additional characters are a nuisance.

Time to ask other people how they manage it as I do very little Network stuff passing real data around. Anybody?

[ClarkVent]

Originally Posted by agraham

No, it's a length indicator, from the BinaryFile help "WriteString ... Writes a string prefixed with its length to the file."

I guess I should RTFM more often...

Anyway, what I eventually did was convert the string to a byte array and send it using WriteBytes2() instead.