Xbase++

Check Whether SSH Channel EOF Was Received

Demonstrates the Chilkat Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has been received for a channel. The only argument is the channel number. EOF means the server will send no more ordinary channel data, but it does not close the channel.

Background: EOF and CLOSE are separate events, and the distinction matters when deciding whether a command has truly finished. A server commonly sends EOF first and CLOSE afterward; in that interval this method is true while ChannelReceivedClose is still false, and the channel remains open and counted. EOF is the signal that all output has been produced — useful when you want to stop reading without waiting for the full close handshake. It returns false for an invalid, released, or locally closed channel.

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LOCAL nSuccess
LOCAL oSsh
LOCAL nSshPort
LOCAL cPassword
LOCAL nChannelNum

nSuccess := 0

//  Demonstrates the Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has
//  been received for a channel.  The only argument is the channel number.  EOF means the server
//  will send no more ordinary channel data, but it does not close the channel.

oSsh := CreateObject("Chilkat.Ssh")

nSshPort := 22
nSuccess := oSsh:Connect("ssh.example.com", nSshPort)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    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.
cPassword := "mySshPassword"

nSuccess := oSsh:AuthenticatePw("mySshLogin", cPassword)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

nChannelNum := oSsh:OpenSessionChannel()
IF (nChannelNum < 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

nSuccess := oSsh:SendReqExec(nChannelNum, "ls -l /tmp")
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

//  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
//  it, this call waits forever if the server never sends channel close.
oSsh:ReadTimeoutMs := 15000

nSuccess := oSsh:ChannelReceiveToClose(nChannelNum)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

IF (oSsh:ChannelReceivedEof(nChannelNum))
    ? "EOF was received -- no more ordinary channel data will arrive."
ELSE
    ? "No EOF has been received."
ENDIF

oSsh:Disconnect()

oSsh:destroy()