Chapter 4. Examples

This chapter demonstrates the use of AMQ Python through example programs.

See the Qpid Proton Python examples for more sample programs.

4.1. Sending messages

This client program connects to a server using <connection-url>, creates a sender for target <address>, sends a message containing <message-body>, closes the connection, and exits.

Example: Sending messages

from __future__ import print_function

import sys

from proton import Message
from proton.handlers import MessagingHandler
from proton.reactor import Container

class SendHandler(MessagingHandler):
    def __init__(self, conn_url, address, message_body):
        super(SendHandler, self).__init__()

        self.conn_url = conn_url
        self.address = address
        self.message_body = message_body

    def on_start(self, event):
        conn = event.container.connect(self.conn_url)
        event.container.create_sender(conn, self.address)

    def on_link_opened(self, event):
        print("SEND: Opened sender for target address '{0}'".format
              (event.sender.target.address))

    def on_sendable(self, event):
        message = Message(self.message_body)
        event.sender.send(message)

        print("SEND: Sent message '{0}'".format(message.body))

        event.sender.close()
        event.connection.close()

def main():
    try:
        conn_url, address, message_body = sys.argv[1:4]
    except ValueError:
        sys.exit("Usage: send.py <connection-url> <address> <message-body>")

    handler = SendHandler(conn_url, address, message_body)
    container = Container(handler)
    container.run()

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        pass

Running the example

To run the example program, copy it to a local file and invoke it using the python command. 

$ python send.py amqp://localhost queue1 hello

4.2. Receiving messages

This client program connects to a server using <connection-url>, creates a receiver for source <address>, and receives messages until it is terminated or it reaches <count> messages.

Example: Receiving messages

from __future__ import print_function

import sys

from proton.handlers import MessagingHandler
from proton.reactor import Container

class ReceiveHandler(MessagingHandler):
    def __init__(self, conn_url, address, desired):
        super(ReceiveHandler, self).__init__()

        self.conn_url = conn_url
        self.address = address
        self.desired = desired
        self.received = 0

    def on_start(self, event):
        conn = event.container.connect(self.conn_url)
        event.container.create_receiver(conn, self.address)

    def on_link_opened(self, event):
        print("RECEIVE: Created receiver for source address '{0}'".format
              (self.address))

    def on_message(self, event):
        message = event.message

        print("RECEIVE: Received message '{0}'".format(message.body))

        self.received += 1

        if self.received == self.desired:
            event.receiver.close()
            event.connection.close()

def main():
    try:
        conn_url, address = sys.argv[1:3]
    except ValueError:
        sys.exit("Usage: receive.py <connection-url> <address> [<message-count>]")

    try:
        desired = int(sys.argv[3])
    except (IndexError, ValueError):
        desired = 0

    handler = ReceiveHandler(conn_url, address, desired)
    container = Container(handler)
    container.run()

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        pass

Running the example

To run the example program, copy it to a local file and invoke it using the python command. 

$ python receive.py amqp://localhost queue1