(PowerShell) WebSocket Send/Receive Binary Data

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.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

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

$ws = New-Object Chilkat.WebSocket

# 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.

$rest = New-Object 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.
$success = $rest.Connect("websockets.chilkat.io",80,$false,$false)
$ws.UseConnection($rest)
$ws.AddClientHeaders()
$responseBodyIgnored = $rest.FullRequestNoBody("GET","/wsChilkatEcho.ashx")
$success = $ws.ValidateServerHandshake()
if ($success -ne $true) {
    $($ws.LastErrorText)
    exit
}

# This example sends a small JPG file (about 7KB) in a websocket frame.
$jpgData = New-Object Chilkat.BinData
$success = $jpgData.LoadFile("qa_data/jpg/starfish.jpg")

$("Number of bytes to send = " + $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.
$finalFrame = $true
$success = $ws.SendFrameBd($jpgData,$finalFrame)
if ($success -ne $true) {
    $($ws.LastErrorText)
    exit
}

# 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.
$receivedFinalFrame = $false
while ($receivedFinalFrame -eq $false) {

    # 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.
    $success = $ws.ReadFrame()
    if ($success -ne $true) {
        $("Failed to receive a frame")
        $("ReadFrame fail reason = " + $ws.ReadFrameFailReason)
        $($ws.LastErrorText)
        exit
    }

    $receivedFinalFrame = $ws.FinalFrame

    # Show the opcode and final frame bit for the frame just received:
    $("Frame opcode: " + $ws.FrameOpcode)
    $("Final frame: " + $receivedFinalFrame)
}

# Get the accumulated received data.
$jpgReceivedData = New-Object Chilkat.BinData
$ws.GetFrameDataBd($jpgReceivedData)
$("Received " + $jpgReceivedData.NumBytes + " bytes")

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

# Close the websocket connection.
$success = $ws.SendClose($true,1000,"Closing this websocket.")
if ($success -ne $true) {
    $($ws.LastErrorText)
    exit
}

# Read the Close response.
$success = $ws.ReadFrame()
if ($success -ne $true) {
    $("ReadFrame fail reason = " + $ws.ReadFrameFailReason)
    $($ws.LastErrorText)
    exit
}

# Should receive the "Close" opcode.
$("Received opcode: " + $ws.FrameOpcode)
# Should be the same status code we sent (1000)
$("Received close status code: " + $ws.CloseStatusCode)
# The server may echo the close reason.  If not, this will be empty.
$("Echoed close reason: " + $ws.CloseReason)

$("Success.")