Tcl

Async Task Chain (another example)

See more Async Examples

Demonstrates using a task chain to run a sequence of FTP tasks asynchronously. Tcl

load ./chilkat.dll

set success 0

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

set success 0

set ftp [new_CkFtp2]

CkFtp2_put_Hostname $ftp "ftp.example.com"
CkFtp2_put_Username $ftp "login"
CkFtp2_put_Password $ftp "password"

# Connect and login to the FTP server.
set success [CkFtp2_Connect $ftp]
if {$success != 1} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    exit
}

set taskChain [new_CkTaskChain]

# Create a task to change to the remote directory where the file will be uploaded.
# task is a CkTask
set task [CkFtp2_ChangeRemoteDirAsync $ftp "junk"]
if {[CkFtp2_get_LastMethodSuccess $ftp] == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    delete_CkTaskChain $taskChain
    exit
}

# Add this task to the task chain.
set success [CkTaskChain_Append $taskChain $task]
delete_CkTask $task

# Create a task to upload a file.
set localFilename "c:/temp/hamlet.xml"
set remoteFilename "hamlet.xml"

set task [CkFtp2_PutFileAsync $ftp $localFilename $remoteFilename]
if {[CkFtp2_get_LastMethodSuccess $ftp] == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    delete_CkTaskChain $taskChain
    exit
}

# Add this task to the task chain.
set success [CkTaskChain_Append $taskChain $task]
delete_CkTask $task

# Start the task chain running in a background thread.
# Each task is run one after the other (on the same background thread) until all tasks have completed.
# The task chain will stop at the first task that fails.
CkTaskChain_put_StopOnFailedTask $taskChain 1
set success [CkTaskChain_Run $taskChain]
if {!$success} then {
    puts [CkTaskChain_lastErrorText $taskChain]
    delete_CkFtp2 $ftp
    delete_CkTaskChain $taskChain
    exit
}

# The application is now free to do anything else
# while the FTP commands are being run...

# For this example, we'll simply sleep and periodically
# check to see if the taskchain if finished. 
while {[CkTaskChain_get_Finished $taskChain] != 1} {

    # Sleep 100 ms.
    CkTaskChain_SleepMs $taskChain 100

}

# A finished task chain could be one that was canceled, aborted, or truly finished.  

# If the task chain "completed", then it ran to completion.  A "completed" task will
# have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
# been aborted or canceled:
if {[CkTaskChain_get_StatusInt $taskChain] != 7} then {
    puts "Task did not complete."
    puts "task chain status: [CkTaskChain_status $taskChain]"
    delete_CkFtp2 $ftp
    delete_CkTaskChain $taskChain
    exit
}

# If we got to this point, the ChangeRemoteDir and PutFile were successful.
# We can visually verify by examining the LastErrorText that was recorded for each
# of these method calls..
set numTasks [CkTaskChain_get_NumTasks $taskChain]
set taskIdx 0

while {$taskIdx < $numTasks} {

    set task [CkTaskChain_GetTask $taskChain $taskIdx]

    # Examine the status of this task, and the ResultErrorText
    # (the ResultErrorText is the ftp.LastErrorText captured for FTP method called by the task).
    # Everything should indicate success.
    puts "task status: [CkTask_status $task]"
    puts "task log: [CkTask_resultErrorText $task]"

    delete_CkTask $task

    set taskIdx [expr $taskIdx + 1]
}

set success [CkFtp2_Disconnect $ftp]

delete_CkFtp2 $ftp
delete_CkTaskChain $taskChain