PowerBuilder

Asynchronous Sockets - Reading/Writing Data

See more Socket/SSL/TLS Examples

Demonstrates the following using async methods:

Demonstrates receiving text on a socket connection up to and including when an expected CRLF arrives. The example sends an HTTP HEAD request to an HTTP server and then reads the response header using ReceiveToCRLF and ReceiveUntilMatch.

PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Socket
integer li_UseTls
integer li_MaxWaitMillisec
oleobject loo_ConnectTask
integer li_ConnectSuccess
oleobject loo_SendTask
integer li_SendSuccess
oleobject loo_ReceiveTask
string ls_ResponseStatusLine
string ls_ResponseHeaderLine
string ls_RemainderOfHeader

li_Success = 0

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

loo_Socket = create oleobject
li_rc = loo_Socket.ConnectToNewObject("Chilkat.Socket")
if li_rc < 0 then
    destroy loo_Socket
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Connect using TLS to www.chilkatsoft.com
// We could also use a normal TCP connection also by specifying port 80 with useTls = 0.
li_UseTls = 1
li_MaxWaitMillisec = 20000
loo_ConnectTask = loo_Socket.ConnectAsync("www.chilkatsoft.com",443,li_UseTls,li_MaxWaitMillisec)
if loo_Socket.LastMethodSuccess <> 1 then
    Write-Debug loo_Socket.LastErrorText
    destroy loo_Socket
    return
end if

// Schedule the task for running on the thread pool.  This changes the task's state
// from Inert to Live.
li_Success = loo_ConnectTask.Run()
if li_Success <> 1 then
    Write-Debug loo_ConnectTask.LastErrorText
    destroy loo_ConnectTask
    destroy loo_Socket
    return
end if

// The application is now free to do anything else.
// For programming languages where Chilkat supports events, a TaskCompleted
// event will fire when the task is completed.

// For this example, we'll simply sleep and periodically
// check to see when the connection is ready.
do while loo_ConnectTask.Finished <> 1

    // Sleep 10 ms.
    loo_ConnectTask.SleepMs(10)

loop

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

// If the task was "canceled", it was canceled prior to actually starting.  This could
// happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
// background thread pool scheduler.  

// If the task was "aborted", it indicates that it was canceled while running in a background thread.  
// The ResultErrorText will likely indicate that the task was aborted.

// If the task "completed", then it ran to completion, but the actual success/failure of the method
// is determined by the result obtained via a GetResult* method.  (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 loo_ConnectTask.StatusInt <> 7 then
    Write-Debug "Task did not complete."
    Write-Debug "task status: " + loo_ConnectTask.Status
    destroy loo_ConnectTask
    destroy loo_Socket
    return
end if

li_ConnectSuccess = loo_ConnectTask.GetResultBool()
if li_ConnectSuccess <> 1 then
    Write-Debug "Connect failed."
    Write-Debug loo_ConnectTask.ResultErrorText
    destroy loo_ConnectTask
    destroy loo_Socket
    return
end if

destroy loo_ConnectTask

// Tell the socket object that all text is to be sent in the utf-8 encoding,
// and the text received is assumed to be utf-8.
loo_Socket.StringCharset = "utf-8"

// Send an HTTP HEAD request:
loo_SendTask = loo_Socket.SendStringAsync("HEAD / HTTP/1.1~r~nHost: www.chilkatsoft.com~r~n~r~n")
if loo_Socket.LastMethodSuccess <> 1 then
    Write-Debug loo_Socket.LastErrorText
    destroy loo_Socket
    return
end if

li_Success = loo_SendTask.Run()
if li_Success <> 1 then
    Write-Debug loo_SendTask.LastErrorText
    destroy loo_SendTask
    destroy loo_Socket
    return
end if

// The application is now free to do anything else.
// For programming languages where Chilkat supports events, 
// a TaskCompleted event will fire when the task is completed.
// This example will simply wait until the task completes...
do while loo_SendTask.Finished <> 1
    // Sleep 10 ms.
    loo_SendTask.SleepMs(10)
loop
if loo_SendTask.StatusInt <> 7 then
    Write-Debug "Task did not complete."
    Write-Debug "task status: " + loo_SendTask.Status
    destroy loo_SendTask
    destroy loo_Socket
    return
end if

li_SendSuccess = loo_SendTask.GetResultBool()
if li_SendSuccess <> 1 then
    Write-Debug "Send failed."
    Write-Debug loo_SendTask.ResultErrorText
    destroy loo_SendTask
    destroy loo_Socket
    return
end if

destroy loo_SendTask

// Wait a maximum of 4 seconds while no data is forthcoming:
loo_Socket.MaxReadIdleMs = 4000

// To explain MaxReadIdleMs further:  In Chilkat, a max "idle timeout" is the max time to wait
// while no additional data arrives on the socket.  Imagine if 10MB of data will be received
// where the 1st CRLF occurs at the very end.  As long as the data continues arriving and does not
// halt for more than 4000ms, then the ReceiveToCRLF will continue receiving.  It is only after
// the connection becomes idle for more than 4000ms that the app will giveup and fail the read.

// Get the 1st response line, which should be "HTTP/1.1 200 OK"
loo_ReceiveTask = loo_Socket.ReceiveToCRLFAsync()
if loo_Socket.LastMethodSuccess <> 1 then
    Write-Debug loo_Socket.LastErrorText
    destroy loo_Socket
    return
end if

li_Success = loo_ReceiveTask.Run()
if li_Success <> 1 then
    Write-Debug loo_ReceiveTask.LastErrorText
    destroy loo_ReceiveTask
    destroy loo_Socket
    return
end if

// The application is now free to do anything else.
// For programming languages where Chilkat supports events, 
// a TaskCompleted event will fire when the task is completed.
// This example will simply wait until the task completes...
do while loo_ReceiveTask.Finished <> 1
    // Sleep 10 ms.
    loo_ReceiveTask.SleepMs(10)
loop
if loo_ReceiveTask.StatusInt <> 7 then
    Write-Debug "Task did not complete."
    Write-Debug "task status: " + loo_ReceiveTask.Status
    destroy loo_ReceiveTask
    destroy loo_Socket
    return
end if

ls_ResponseStatusLine = loo_ReceiveTask.GetResultString()

Write-Debug "StatusLine: " + ls_ResponseStatusLine
destroy loo_ReceiveTask

// Now get the 1st line of the response header:
ls_ResponseHeaderLine = loo_Socket.ReceiveToCRLF()
if loo_Socket.LastMethodSuccess <> 1 then
    Write-Debug loo_Socket.LastErrorText
    destroy loo_Socket
    return
end if

Write-Debug "HeaderLine: " + ls_ResponseHeaderLine

// Now read the remainder of the response header by reading until a double CRLF is seen:
loo_ReceiveTask = loo_Socket.ReceiveUntilMatchAsync("~r~n~r~n")
if loo_Socket.LastMethodSuccess <> 1 then
    Write-Debug loo_Socket.LastErrorText
    destroy loo_Socket
    return
end if

li_Success = loo_ReceiveTask.Run()
if li_Success <> 1 then
    Write-Debug loo_ReceiveTask.LastErrorText
    destroy loo_ReceiveTask
    destroy loo_Socket
    return
end if

// The application is now free to do anything else.
// For programming languages where Chilkat supports events, 
// a TaskCompleted event will fire when the task is completed.
// This example will simply wait until the task completes...
do while loo_ReceiveTask.Finished <> 1
    // Sleep 10 ms.
    loo_ReceiveTask.SleepMs(10)
loop
if loo_ReceiveTask.StatusInt <> 7 then
    Write-Debug "Task did not complete."
    Write-Debug "task status: " + loo_ReceiveTask.Status
    destroy loo_ReceiveTask
    destroy loo_Socket
    return
end if

ls_RemainderOfHeader = loo_ReceiveTask.GetResultString()

Write-Debug "Remainder: " + ls_RemainderOfHeader
destroy loo_ReceiveTask

// Close the connection with the server
// Wait a max of 20 seconds (20000 millsec)
li_Success = loo_Socket.Close(20000)


destroy loo_Socket