（转）pika详解(三)SelectConnection及其他Connection

原文：https://blog.csdn.net/comprel/article/details/94661147

pika除了block connection外还提供了其他非阻塞式的连接方式

SelectConnection

定义如下：

class SelectConnection(BaseConnection):
def __init__(
self, # pylint: disable=R0913
parameters=None,
on_open_callback=None,
on_open_error_callback=None,
on_close_callback=None,
custom_ioloop=None,
internal_connection_workflow=True):
"""Create a new instance of the Connection object.

:param pika.connection.Parameters parameters: Connection parameters
:param callable on_open_callback: Method to call on connection open
:param None | method on_open_error_callback: Called if the connection
can't be established or connection establishment is interrupted by
`Connection.close()`: on_open_error_callback(Connection, exception).
:param None | method on_close_callback: Called when a previously fully
open connection is closed:
`on_close_callback(Connection, exception)`, where `exception` is
either an instance of `exceptions.ConnectionClosed` if closed by
user or broker or exception of another type that describes the cause
of connection failure.
:param None | IOLoop | nbio_interface.AbstractIOServices custom_ioloop:
Provide a custom I/O Loop object.
:param bool internal_connection_workflow: True for autonomous connection
establishment which is default; False for externally-managed
connection workflow via the `create_connection()` factory.
:raises: RuntimeError

"""
if isinstance(custom_ioloop, nbio_interface.AbstractIOServices):
nbio = custom_ioloop
else:
nbio = SelectorIOServicesAdapter(custom_ioloop or IOLoop())

super(SelectConnection, self).__init__(
parameters,
on_open_callback,
on_open_error_callback,
on_close_callback,
nbio,
internal_connection_workflow=internal_connection_workflow)

@classmethod
def create_connection(cls,
connection_configs,
on_done,
custom_ioloop=None,
workflow=None):
"""Implement
:py:classmethod:`pika.adapters.BaseConnection.create_connection()`.

"""
nbio = SelectorIOServicesAdapter(custom_ioloop or IOLoop())

def connection_factory(params):
"""Connection factory."""
if params is None:
raise ValueError('Expected pika.connection.Parameters '
'instance, but got None in params arg.')
return cls(
parameters=params,
custom_ioloop=nbio,
internal_connection_workflow=False)

return cls._start_connection_workflow(
connection_configs=connection_configs,
connection_factory=connection_factory,
nbio=nbio,
workflow=workflow,
on_done=on_done)

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SelectConnection继承BaseConnection，只是重写了create_connection

在create_connection 中可以看到：

nbio = SelectorIOServicesAdapter(custom_ioloop or IOLoop())

说明这个类实现的 select IO

提供的函数、方法解析：

add_on_close_callback
关闭时候的回调， callback定义 callback（pika.connection.Connection，exception）

add_on_connection_blocked_callback
阻塞时候回调 回调定义： callback(connection, pika.frame.Method)

add_on_connection_unblocked_callback

解除阻塞时候回调

add_on_open_callback

打开时回调

add_on_open_error_callback

打开异常时候回调

basic_nack
channel（channel_number = None*，*on_open_callback = None ）
建立通道

channel_number（int） - 要使用的通道编号，默认为下一个可用通道编号。
on_open_callback（callable）

close
consumer_cancel_notify
定服务器是否支持活动连接上的使用者取消通知 返回bool值

create_connection(connection_configs, on_done, custom_ioloop=None, workflow=None)
建立连接

exchange_exchange_bindings

返回值bool 是否支持交换机修改

ioloop

is_closed

is_closing

is_open

publisher_confirms

是否支持发布确认

Tornado Connection Adapter

方法可参考基类BaseConnection

略

Twisted Connection Adapter

方法可参考基类BaseConnection

略

 

标签：SelectConnection,ioloop,None,pika,workflow,Connection,callback,connection,open
来源： https://www.cnblogs.com/liujiacai/p/15489574.html