Perl

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.

Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

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

my $ws = Chilkat2::WebSocket->new;

# 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.

my $rest = Chilkat2::Rest->new;
# 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.
my $success = $rest->Connect('websockets.chilkat.io', 80, 0, 0);
$ws->UseConnection($rest);
$ws->AddClientHeaders();
my $responseBodyIgnored = $rest->FullRequestNoBody('GET', '/wsChilkatEcho.ashx');
$success = $ws->ValidateServerHandshake();
if (!$success) {
    print $ws->LastErrorText, "\n";
    exit;
}

# This example sends a small JPG file (about 7KB) in a websocket frame.
my $jpgData = Chilkat2::BinData->new;
$success = $jpgData->LoadFile('qa_data/jpg/starfish.jpg');

print 'Number of bytes to send = ', $jpgData->NumBytes, "\n";

# Send a frame containing the JPG image data.
# This will be the first and final frame, and therefore this constitutes the entire message.
my $finalFrame = 1;
$success = $ws->SendFrameBd($jpgData, $finalFrame);
if (!$success) {
    print $ws->LastErrorText, "\n";
    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.
my $receivedFinalFrame = 0;
while (!$receivedFinalFrame) {
    # 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) {
        print "Failed to receive a frame\n";
        print 'ReadFrame fail reason = ', $ws->ReadFrameFailReason, "\n";
        print $ws->LastErrorText, "\n";
        exit;
    }

    $receivedFinalFrame = $ws->FinalFrame;

    # Show the opcode and final frame bit for the frame just received:
    print 'Frame opcode: ', $ws->FrameOpcode, "\n";
    print 'Final frame: ', ($receivedFinalFrame ? 1 : 0), "\n";
}

# Get the accumulated received data.
my $jpgReceivedData = Chilkat2::BinData->new;
$ws->GetFrameDataBd($jpgReceivedData);
print 'Received ', $jpgReceivedData->NumBytes, " bytes\n";

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

# Close the websocket connection.
$success = $ws->SendClose(1, 1000, 'Closing this websocket.');
if (!$success) {
    print $ws->LastErrorText, "\n";
    exit;
}

# Read the Close response.
$success = $ws->ReadFrame();
if (!$success) {
    print 'ReadFrame fail reason = ', $ws->ReadFrameFailReason, "\n";
    print $ws->LastErrorText, "\n";
    exit;
}

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

print "Success.\n";