CkPython

Get Received SSH Text into a StringBuilder

Demonstrates the Chilkat Ssh.GetReceivedSb method, which decodes a channel's receive buffer and appends the text to a StringBuilder. The arguments are the channel number, the charset, and the StringBuilder. The receive buffer is cleared afterward.

Background: Because this appends rather than replaces, it is the natural choice for accumulating output across repeated reads — call it in a loop and the StringBuilder grows into the complete transcript. It also avoids creating a new string on every retrieval, which matters when a command produces a large amount of text.

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import sys
import chilkat

success = False

#  Demonstrates the Ssh.GetReceivedSb method, which decodes the channel's receive buffer and
#  appends the text to a StringBuilder.  The 1st argument is the channel number, the 2nd is the
#  charset, and the 3rd is the StringBuilder.  The receive buffer is cleared afterward.

ssh = chilkat.CkSsh()

sshPort = 22
success = ssh.Connect("ssh.example.com",sshPort)
if (success == False):
    print(ssh.lastErrorText())
    sys.exit()

#  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.
password = "mySshPassword"

success = ssh.AuthenticatePw("mySshLogin",password)
if (success == False):
    print(ssh.lastErrorText())
    sys.exit()

channelNum = ssh.OpenSessionChannel()
if (channelNum < 0):
    print(ssh.lastErrorText())
    sys.exit()

success = ssh.SendReqExec(channelNum,"ls -l /tmp")
if (success == False):
    print(ssh.lastErrorText())
    sys.exit()

#  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.
ssh.put_ReadTimeoutMs(15000)

success = ssh.ChannelReceiveToClose(channelNum)
if (success == False):
    print(ssh.lastErrorText())
    sys.exit()

#  Append the received text to a StringBuilder.  Existing content is preserved.
sb = chilkat.CkStringBuilder()
success = ssh.GetReceivedSb(channelNum,"utf-8",sb)
if (success == False):
    print(ssh.lastErrorText())
    sys.exit()

print("Characters received: " + str(sb.get_Length()))
output = sb.getAsString()
print(output)

ssh.Disconnect()