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Get Received SSH Bytes into a BinData

Demonstrates the Chilkat Ssh.GetReceivedBd method, which appends the bytes currently in a channel's normal receive buffer to a BinData. The first argument is the channel number and the second is the BinData. The channel receive buffer is cleared afterward; existing bytes in the BinData are preserved.

Background: When the remote command emits binary — a tarball, an image, a compressed stream — decoding it as text through a charset would corrupt it. BinData keeps the bytes exactly as received, so you can write them to a file, hash them, or hand them to another API. Like the StringBuilder form it appends, making it easy to accumulate across successive reads. On failure the BinData is left unchanged.

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llSuccess = .F.

//  Demonstrates the Ssh.GetReceivedBd method, which appends the bytes currently in a channel's
//  receive buffer to a BinData.  The 1st argument is the channel number and the 2nd is the
//  BinData.  The channel receive buffer is cleared afterward.

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

lnChannelNum = loSsh.OpenSessionChannel()
if (lnChannelNum < 0) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  Run a command whose output may be binary.
llSuccess = loSsh.SendReqExec(lnChannelNum,"cat /usr/bin/hostname")
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    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.
loSsh.ReadTimeoutMs = 15000

llSuccess = loSsh.ChannelReceiveToClose(lnChannelNum)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  Append the raw received bytes to a BinData.  Existing bytes in the BinData are preserved.
loBd = createobject("CkBinData")
llSuccess = loSsh.GetReceivedBd(lnChannelNum,loBd)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    release loBd
    return
endif

? "Bytes received: " + str(loBd.NumBytes)

loSsh.Disconnect()


release loSsh
release loBd