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(Python) HTTP in a Background Thread (Asynchronous HTTP)This example shows the technique one would follow to run any Chilkat HTTP method in a background task. (Only HTTP methods that communicate with an HTTP server are background-enabled. Methods that perform no HTTP communications return immediately and never need to be backgrounded.)
import sys import chilkat http = chilkat.CkHttp() # Any string unlocks the component for the 1st 30-days. success = http.UnlockComponent("Anything for 30-day trial") if (success != True): print http.lastErrorText() sys.exit() # To run an HTTP method asynchronously in a background thread, set # the UseBgThread property equal to True http.put_UseBgThread(True) # For those programming languages that support event callbacks: # events are not fired when a task is running in the background thread. # Instead, Chilkat has added the "event log" mechanism. While the # background task is running, events that normally would've been fired # are accumulated in the event log. Your application may periodically check # the event log to keep track of the progress of the background task. # To enable event logging, set the KeepEventLog property = True http.put_KeepEventLog(True) # Start an asynchronous HTTP download in a background thread. # The method will return cktrue if the task was successfully started. # Note: When the UseBgThread property = True, all methods involving # HTTP communications will be asynchronous. These methods include: # SynchronousRequest, QuickGetStr, QuickGet, PostUrlEncoded, XmlRpc, # XmlRpcPut, QuickPutStr, QuickGetObj, QuickDeleteStr, PutText, # PutBinary, PostBinary, PostMime, GetHead, DownloadAppend, etc. success = http.Download("http://www.chilkatsoft.com/download/ChilkatJava.zip","ChilkatJava.zip") if (success != True): print http.lastErrorText() sys.exit() else: print "Initiated asynchronous HTTP download..." # Write a loop to wait for the background task to complete. # Your application would typically do something different than this -- # after all... there's no point in doing the task asynchronously if your application # is simply going to wait for it to complete -- that's the same as doing it synchronously, # and that could've been achieved by a single call to the http.Download method # with the UseBgThread = False. # However... we do this here for the purpose of demonstration... while (http.get_BgTaskRunning() == True) : # Show the events in the event log that have accumulated so far... n = http.get_EventLogCount() if (n > 0): for i in range(0,n): print http.eventLogName(i) + ": "\ + http.eventLogValue(i) http.ClearBgEventLog() # In some programming languages, you might wish to handle user-interface events # For example, in C# you might call Application.DoEvents() # Sleep .1 seconds -- to keep the CPU from being 100% busy... http.SleepMs(100) # Once the background task has completed, check it for success/failure: if (http.get_BgTaskSuccess()): print "Background task completed successfully." |
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