PowerBuilder

WebSocket Send/Receive Binary Data

See more WebSocket Examples

Demonstrates how to send and receive binary data on a websocket. This example uses Chilkat's websocket test echo server at ws://websockets.chilkat.io/wsChilkatEcho.ashx

Note: The websockets.chilkat.io server imposes the following limitations:
Messages must be 16K or less, and each connection is limited to a max of 16 echoed messages.

PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Ws
oleobject loo_Rest
string ls_ResponseBodyIgnored
oleobject loo_JpgData
integer li_FinalFrame
integer li_ReceivedFinalFrame
oleobject loo_JpgReceivedData

li_Success = 0

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

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

// For brevity, this example does not check for errors when etablishing the WebSocket connection.
// See Establish WebSocket Connection for more complete sample code for making the connection.

loo_Rest = create oleobject
li_rc = loo_Rest.ConnectToNewObject("Chilkat.Rest")

// Connect to websockets.chilkat.io
// IMPORTANT: websockets.chilkat.io accepts frames of up to 16K in size and echoes them back.
// IMPORTANT: The websockets.chilkat.io server imposes the following limitations: 
// ---------- Messages must be 16K or less, and each connection is limited to a max of 16 echoed messages.
li_Success = loo_Rest.Connect("websockets.chilkat.io",80,0,0)
loo_Ws.UseConnection(loo_Rest)
loo_Ws.AddClientHeaders()
ls_ResponseBodyIgnored = loo_Rest.FullRequestNoBody("GET","/wsChilkatEcho.ashx")
li_Success = loo_Ws.ValidateServerHandshake()
if li_Success <> 1 then
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    return
end if

// This example sends a small JPG file (about 7KB) in a websocket frame.
loo_JpgData = create oleobject
li_rc = loo_JpgData.ConnectToNewObject("Chilkat.BinData")

li_Success = loo_JpgData.LoadFile("qa_data/jpg/starfish.jpg")

Write-Debug "Number of bytes to send = " + string(loo_JpgData.NumBytes)

// Send a frame containing the JPG image data.
// This will be the first and final frame, and therefore this constitutes the entire message.
li_FinalFrame = 1
li_Success = loo_Ws.SendFrameBd(loo_JpgData,li_FinalFrame)
if li_Success <> 1 then
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    destroy loo_JpgData
    return
end if

// Read the echoed binary frame(s).
// (We sent the JPG file in a single frame, but we may receive the echo in multiple frames, but it will be one message.)
// Read an incoming frames until we receive the final frame.
li_ReceivedFinalFrame = 0
do while li_ReceivedFinalFrame = 0

    // The ws object is accumulating the received data internally.  Once we get the final frame, we'll get the 
    // accumulated data which should constitute the entire JPG.
    li_Success = loo_Ws.ReadFrame()
    if li_Success <> 1 then
        Write-Debug "Failed to receive a frame"
        Write-Debug "ReadFrame fail reason = " + string(loo_Ws.ReadFrameFailReason)
        Write-Debug loo_Ws.LastErrorText
        destroy loo_Ws
        destroy loo_Rest
        destroy loo_JpgData
        return
    end if

    li_ReceivedFinalFrame = loo_Ws.FinalFrame

    // Show the opcode and final frame bit for the frame just received:
    Write-Debug "Frame opcode: " + loo_Ws.FrameOpcode
    Write-Debug "Final frame: " + string(li_ReceivedFinalFrame)
loop

// Get the accumulated received data.
loo_JpgReceivedData = create oleobject
li_rc = loo_JpgReceivedData.ConnectToNewObject("Chilkat.BinData")

loo_Ws.GetFrameDataBd(loo_JpgReceivedData)
Write-Debug "Received " + string(loo_JpgReceivedData.NumBytes) + " bytes"

// Save the received JPG to a file so we can check it..
loo_JpgReceivedData.WriteFile("qa_output/starfish_ws.jpg")

// Close the websocket connection.
li_Success = loo_Ws.SendClose(1,1000,"Closing this websocket.")
if li_Success <> 1 then
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    destroy loo_JpgData
    destroy loo_JpgReceivedData
    return
end if

// Read the Close response.
li_Success = loo_Ws.ReadFrame()
if li_Success <> 1 then
    Write-Debug "ReadFrame fail reason = " + string(loo_Ws.ReadFrameFailReason)
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    destroy loo_JpgData
    destroy loo_JpgReceivedData
    return
end if

// Should receive the "Close" opcode.
Write-Debug "Received opcode: " + loo_Ws.FrameOpcode
// Should be the same status code we sent (1000)
Write-Debug "Received close status code: " + string(loo_Ws.CloseStatusCode)
// The server may echo the close reason.  If not, this will be empty.
Write-Debug "Echoed close reason: " + loo_Ws.CloseReason

Write-Debug "Success."


destroy loo_Ws
destroy loo_Rest
destroy loo_JpgData
destroy loo_JpgReceivedData