Chilkat2-Python

Send a WebSocket Ping Control Frame

See more WebSocket Examples

Ping and Pong messages are the heartbeat of websockets. See WebSocket_servers#Pings_and_Pongs_The_Heartbeat_of_WebSockets">Pings and Pongs

"At any point after the handshake, either the client or the server can choose to send a ping to the other party. When the ping is received, the recipient must send back a pong as soon as possible. You can use this to make sure that the client is still connected, for example. A ping or pong is just a regular frame, but it's a control frame. Pings have an opcode of 0x9, and pongs have an opcode of 0xA. When you get a ping, send back a pong with the exact same Payload Data as the ping (for pings and pongs, the max payload length is 125). You might also get a pong without ever sending a ping; ignore this if it happens."

This example demonstrates how to send a Ping in the midst of sending a message.

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-Python

import sys
import chilkat2

success = False

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

ws = chilkat2.WebSocket()

# The PongAutoConsume property is True by default.  This means that any Pong frames that are received 
# will automatically be consumed, and the ReadFrame method will continue reading the next incoming frame before it returns.
ws.PongAutoConsume = True

# 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 = chilkat2.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 != True):
    print(ws.LastErrorText)
    sys.exit()

# This example sends a multi-frame message to the Chilkat echo server, and reads the response.
# In the midst of sending the message, we'll send a Ping control frame.  The server should respond with a Pong frame,
# and we'll automatically consume it.

# Send the 1st frame in the message.
finalFrame = False
success = ws.SendFrame("This is the 1st frame\r\n",finalFrame)
if (success != True):
    print(ws.LastErrorText)
    sys.exit()

# Let's send a Ping frame here...
success = ws.SendPing("This is a ping")
if (success != True):
    print(ws.LastErrorText)
    sys.exit()

# Send the 2nd frame in the message.
success = ws.SendFrame("This is the 2nd frame\r\n",finalFrame)
if (success != True):
    print(ws.LastErrorText)
    sys.exit()

# Send the 3rd and final frame in the message.
finalFrame = True
success = ws.SendFrame("This is the 3rd and final frame\r\n",finalFrame)
if (success != True):
    print(ws.LastErrorText)
    sys.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.
# 
# The Pong response will be consumed automatically because the PongAutoConsume property is True.
# Therefore, we don't need to worry about handling an incoming Pong.
receivedFinalFrame = False
while receivedFinalFrame == False :

    success = ws.ReadFrame()
    if (success != True):
        print("Failed to receive a frame")
        print("ReadFrame fail reason = " + str(ws.ReadFrameFailReason))
        print(ws.LastErrorText)
        sys.exit()

    receivedFinalFrame = ws.FinalFrame

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

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

# Close the websocket connection.
success = ws.SendClose(True,1000,"Closing this websocket.")
if (success != True):
    print(ws.LastErrorText)
    sys.exit()

# Read the Close response.
success = ws.ReadFrame()
if (success != True):
    print("ReadFrame fail reason = " + str(ws.ReadFrameFailReason))
    print(ws.LastErrorText)
    sys.exit()

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

print("Success.")