Ruby

Multiple SendReqExec on the Same Connection

Demonstrates running a series of commands on one SSH connection using SendReqExec. Each exec request requires its own logical channel — this is not a separate SSH connection, just a new session channel on the existing one.

Background: An SSH session channel is single-use for an exec request: once the command runs and the server closes the channel, that channel cannot be reused. Opening a fresh channel per command is cheap, since the expensive work — the TCP connection, key exchange, and authentication — is done once and shared. This is why running ten commands over one connection is far faster than connecting ten times.

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Ruby

require 'chilkat'

success = false

#  This example requires the Chilkat API to have been previously unlocked.
#  See Global Unlock Sample for sample code.

#  Demonstrates running a series of commands on one SSH connection using SendReqExec.  Each exec
#  request requires its own logical channel.  This is not a new SSH connection -- it is simply a
#  new session channel on the existing one.

ssh = Chilkat::CkSsh.new()

hostname = "ssh.example.com"
port = 22
success = ssh.Connect(hostname,port)
if (success == false)
    print ssh.lastErrorText() + "\n";
    exit
end

#  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() + "\n";
    exit
end

#  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)

#  ---- 1st command, on its own session channel ----
channelNum = ssh.OpenSessionChannel()
if (channelNum < 0)
    print ssh.lastErrorText() + "\n";
    exit
end

success = ssh.SendReqExec(channelNum,"ls -al")
if (success == false)
    print ssh.lastErrorText() + "\n";
    exit
end

success = ssh.ChannelReceiveToClose(channelNum)
if (success == false)
    print ssh.lastErrorText() + "\n";
    exit
end

cmdOutput = ssh.getReceivedText(channelNum,"utf-8")
if (ssh.get_LastMethodSuccess() == false)
    print ssh.lastErrorText() + "\n";
    exit
end

print cmdOutput + "\n";
print "----" + "\n";

#  ---- 2nd command, on a NEW session channel over the same connection ----
channelNum = ssh.OpenSessionChannel()
if (channelNum < 0)
    print ssh.lastErrorText() + "\n";
    exit
end

success = ssh.SendReqExec(channelNum,"nslookup chilkatsoft.com")
if (success == false)
    print ssh.lastErrorText() + "\n";
    exit
end

success = ssh.ChannelReceiveToClose(channelNum)
if (success == false)
    print ssh.lastErrorText() + "\n";
    exit
end

cmdOutput = ssh.getReceivedText(channelNum,"utf-8")
if (ssh.get_LastMethodSuccess() == false)
    print ssh.lastErrorText() + "\n";
    exit
end

print cmdOutput + "\n";

ssh.Disconnect()