(PowerShell) Send and Receive WebSocket Messages

This example how to send and receive websocket messages.

A WebSocket message can be composed of one or more frames. The simple case is where a single frame is both the first and last frame in a message. This is the case where the 1st frame in the message has the "final frame" bit set.

This example demonstrates sending and receiving multi-frame messages.

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.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-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 demonstrates sending and receiving a multi-frame message.

# The websocket message will be composed of three text lines, each frame will contain a single line.

# Send the 1st frame in the message.
$finalFrame = $false
$success = $ws.SendFrame("This is the 1st frame`r`n",$finalFrame)
if ($success -ne $true) {
    $($ws.LastErrorText)
    exit
}

# Send the 2nd frame in the message.
$success = $ws.SendFrame("This is the 2nd frame`r`n",$finalFrame)
if ($success -ne $true) {
    $($ws.LastErrorText)
    exit
}

# Send the 3rd and final frame in the message.
$finalFrame = $true
$success = $ws.SendFrame("This is the 3rd frame`r`n",$finalFrame)
if ($success -ne $true) {
    $($ws.LastErrorText)
    exit
}

# Read an incoming frames until we receive the final frame.
# Note: It may be that the echo server (websockets.chilkat.io) responds with 
# the full message in a single final frame.
$receivedFinalFrame = $false
while ($receivedFinalFrame -eq $false) {

    $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)
}

# Return the message accumulated in the above calls to ReadFrame.
$receivedMsg = $ws.GetFrameData()
$("Received: " + $receivedMsg)

# 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.")