Tcl

Cancel HTTP Get Async Task if not Completed after a Max Time

See more HTTP Examples

Demonstrates how to wait a maximum amount of time for an asynchronous task to completed. If not completed in the allotted amount of time, the task is cancelled. Tcl

load ./chilkat.dll

set success 0

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

set http [new_CkHttp]

# Set some timeouts, in seconds:
CkHttp_put_ConnectTimeout $http 15
# ReadTimeout specifies the max number of seconds that must elapse when no additional data is received before
# timing out.  For example, if a server sends a 300 byte response at the rate of 1 byte per second, then
# ReadTimeout would never cause a timeout because there is never a 15 second interval when nothing arrives.
CkHttp_put_ReadTimeout $http 15

set url "https://your-url.com/something"
# task is a CkTask
set task [CkHttp_QuickGetStrAsync $http $url]
CkTask_Run $task

# Wait a maximum of waitMaxMs for the task (i.e. the HTTP GET) to complete.
# The Wait method returns when the task has been canceled, aborted, or completed, or when the max allotted time has passed.
set waitMaxMs 20000
CkTask_Wait $task $waitMaxMs

# At this point, the GET may or may not have completed.  
# Rather than checking the Task status, we can call task.Cancel because
# if the Task is no longer running (because it already completed, was canceled or aborted), then the 
# call to Cancel is a NO-OP (meaning it does nothing and the Task's status is unaffected).
# Also, task.Cancel returns 1 if the task was in the "queued" or "running" state and was canceled or aborted. 
# The method returns 0 if the task has any other status.
set wasCanceled [CkTask_Cancel $task]
if {$wasCanceled == 1} then {
    puts "The HTTP GET took too long and was canceled."
} else {
    # Find out what happened.
    if {[CkTask_get_StatusInt $task] == 7} then {
        # The task completed, which means the background thread's call to QuickGetStr completed
        # with success or failure.  Find out which...
        if {[CkTask_get_TaskSuccess $task] == 1} then {
            # Get the string response for the call to QuickGetStr (which happened in Chilkat's background thread).
            set responseStr [CkTask_getResultString $task]
            puts "$responseStr"
            puts "HTTP GET successful!"
        }         else {
            puts "HTTP GET failed prior to waitMaxMs..."
            puts [CkTask_resultErrorText $task]
        }

    }     else {
        # The task must've been canceled or aborted by some other means..
        puts "Task did not complete.  Final status: [CkTask_status $task]"
    }

}

delete_CkTask $task


delete_CkHttp $http