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Chapter 4. Examples

This chapter demonstrates the use of AMQ Python through example programs. To run them, make sure you have completed the steps in the Chapter 2, Installation chapter for your environment and you have a running and configured broker.

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