(Tcl) Multiple SendReqExec on Same Connection

Shows how to execute a series of commands on an SSH server and retrieve each command's output (using SendReqExec). Each call to SendReqExec requires its own logical channel. This is not a separate SSH connection -- it's simply a new session channel on the existing SSH connection.

Chilkat Tcl Extension Downloads Chilkat Tcl Extension Downloads

load ./chilkat.dll

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

set ssh [new_CkSsh]

# Hostname may be an IP address or domain:
set hostname "172.16.16.46"
set port 22

set success [CkSsh_Connect $ssh $hostname $port]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# If receiving output from a command stalls for more than 5 seconds, then stop waiting.
CkSsh_put_IdleTimeoutMs $ssh 5000

# Authenticate using login/password:
set success [CkSsh_AuthenticatePw $ssh "myLogin" "myPassword"]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Open a session channel.  (It is possible to have multiple
# session channels open simultaneously.)
set channelNum [CkSsh_OpenSessionChannel $ssh]
if {$channelNum < 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Request a directory listing on the remote server:
# If your server is Linux/UNIX, change the string from "dir" to "ls"
# Note: Some SSH servers require a CRLF instead of a bare-LF
set cmd "ls -al\n"
set success [CkSsh_SendReqExec $ssh $channelNum $cmd]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Read whatever output may already be available on the
# SSH connection.  ChannelReadAndPoll returns the number of bytes
# that are available in the channel's internal buffer that
# are ready to be "picked up" by calling GetReceivedText
# or GetReceivedData.
# A return value of -1 indicates failure.
# A return value of -2 indicates a failure via timeout.

# The ChannelReadAndPoll method waits
# for data to arrive on the connection usingi the IdleTimeoutMs
# property setting.  Once the first data arrives, it continues
# reading but instead uses the pollTimeoutMs passed in the 2nd argument:
# A return value of -2 indicates a timeout where no data is received.
set pollTimeoutMs 2000
set n [CkSsh_ChannelReadAndPoll $ssh $channelNum $pollTimeoutMs]
if {$n < 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Close the channel:
set success [CkSsh_ChannelSendClose $ssh $channelNum]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Perhaps we did not receive all of the commands output.
# To make sure,  call ChannelReceiveToClose to accumulate any remaining
# output until the server's corresponding "channel close" is received.
set success [CkSsh_ChannelReceiveToClose $ssh $channelNum]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Get the accumulated output of the command:

set cmdOutput [CkSsh_getReceivedText $ssh $channelNum "ansi"]
if {[CkSsh_get_LastMethodSuccess $ssh] == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Display the remote shell's command output:
puts "$cmdOutput"
puts "----"

# -----------------------------------------------------------------
# Now for the 2nd SendReqExe (on the same connection,
# but on a separate logical channel).
# -----------------------------------------------------------------

set channelNum [CkSsh_OpenSessionChannel $ssh]
if {$channelNum < 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

set cmd "nslookup chilkatsoft.com\n"
set success [CkSsh_SendReqExec $ssh $channelNum $cmd]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

set pollTimeoutMs 2000
set n [CkSsh_ChannelReadAndPoll $ssh $channelNum $pollTimeoutMs]
if {$n < 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

set success [CkSsh_ChannelSendClose $ssh $channelNum]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

set success [CkSsh_ChannelReceiveToClose $ssh $channelNum]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

set cmdOutput [CkSsh_getReceivedText $ssh $channelNum "ansi"]
if {[CkSsh_get_LastMethodSuccess $ssh] == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

puts "$cmdOutput"

delete_CkSsh $ssh