Question

我试图通过介绍pika（http://pika.readthedocs.io/en/0.10.0/intro.html#io-and-event-looping）来理解这个代码示例：

import pika

# Create a global channel variable to hold our channel object in
channel = None

# Step #2
def on_connected(connection):
    """Called when we are fully connected to RabbitMQ"""
    # Open a channel
    connection.channel(on_channel_open)

# Step #3
def on_channel_open(new_channel):
    """Called when our channel has opened"""
    global channel
    channel = new_channel
    channel.queue_declare(queue="test", durable=True, exclusive=False, auto_delete=False, callback=on_queue_declared)

# Step #4
def on_queue_declared(frame):
    """Called when RabbitMQ has told us our Queue has been declared, frame is the response from RabbitMQ"""
    channel.basic_consume(handle_delivery, queue='test')

# Step #5
def handle_delivery(channel, method, header, body):
    """Called when we receive a message from RabbitMQ"""
    print body

# Step #1: Connect to RabbitMQ using the default parameters
parameters = pika.ConnectionParameters()
connection = pika.SelectConnection(parameters, on_connected)

try:
    # Loop so we can communicate with RabbitMQ
    connection.ioloop.start()
except KeyboardInterrupt:
    # Gracefully close the connection
    connection.close()
    # Loop until we're fully closed, will stop on its own
    connection.ioloop.start()

根据handle_delivery的文档字符串，当我们从RabbitMQ收到消息时应该调用它。但是，我没有看到代码中稍后引用handle_delivery，也没有在pika 0.10.0源代码中找到它的任何出现：

kurt@kurt-ThinkPad:~/dev/scratch/pika-0.10.0$ grep -r "handle_delivery"
kurt@kurt-ThinkPad:~/dev/scratch/pika-0.10.0$

那么handle_delivery如何获得＆＃39;由connection？

Answer 1

step4将频道与handle_deivery函数相关联。

# Step #4
def on_queue_declared(frame):
    """Called when RabbitMQ has told us our Queue has been declared, frame is the response from RabbitMQ"""
    channel.basic_consume(handle_delivery, queue='test')

频道与步骤＃2中的连接相关联

# Step #2
def on_connected(connection):
    """Called when we are fully connected to RabbitMQ"""
    # Open a channel
    connection.channel(on_channel_open)

＆＃34; handle_delivery＆＃34;在Python的pika中实现的方法？

1 个答案: