Lianja

Check Whether an SSH Channel is Open

Demonstrates the Chilkat Ssh.ChannelIsOpen method, which reports whether a channel number identifies a channel Chilkat currently considers open for application I/O. The only argument is the channel number. This example checks the channel before and after sending CLOSE.

Background: Because one SSH connection can carry many channels with independent lifetimes, code that manages several needs a way to ask whether a given one is still usable. This returns false for invalid or nonexistent channel numbers, after a local Disconnect, once remote closure is processed, and immediately after ChannelSendClose — which marks the channel locally closed without waiting for the remote side.

Chilkat Lianja Downloads

Download Chilkat for Lianja

Lianja

llSuccess = .F.

//  Demonstrates the Ssh.ChannelIsOpen method, which reports whether a channel number identifies
//  a channel Chilkat currently considers open for application I/O.  The only argument is the
//  channel number.

loSsh = createobject("CkSsh")

lnSshPort = 22
llSuccess = loSsh.Connect("ssh.example.com",lnSshPort)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
lcPassword = "mySshPassword"

llSuccess = loSsh.AuthenticatePw("mySshLogin",lcPassword)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  Open a session channel.  A negative return value indicates failure.
lnChannelNum = loSsh.OpenSessionChannel()
if (lnChannelNum < 0) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

if (loSsh.ChannelIsOpen(lnChannelNum)) then
    ? "The channel is open."
else
    ? "The channel is not open."
endif

//  Send CLOSE, which immediately marks the channel locally closed.
llSuccess = loSsh.ChannelSendClose(lnChannelNum)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

if (loSsh.ChannelIsOpen(lnChannelNum)) then
    ? "Still open."
else
    ? "The channel is now closed."
endif

loSsh.Disconnect()


release loSsh