The main direction for
asyncio
extending is writing custom
事件循环
classes. Asyncio has helpers that could be used to simplify this task.
注意
Third-parties should reuse existing asyncio code with caution, a new Python version is free to break backward compatibility in internal part of API.
asyncio.AbstractEventLoop
declares very many methods. Implementing all them from scratch is a tedious job.
A loop can get many common methods implementation for free by inheriting from
asyncio.BaseEventLoop
.
In turn, the successor should implement a bunch of
private
methods declared but not implemented in
asyncio.BaseEventLoop
.
例如，
loop.create_connection()
checks arguments, resolves DNS addresses, and calls
loop._make_socket_transport()
that should be implemented by inherited class. The
_make_socket_transport()
method is not documented and is considered as an
internal
API。
asyncio.Future
and
asyncio.Task
should be never created directly, please use corresponding
loop.create_future()
and
loop.create_task()
，或
asyncio.create_task()
factories instead.
However, third-party 事件循环 may reuse built-in future and task implementations for the sake of getting a complex and highly optimized code for free.
For this purpose the following, private constructors are listed:
创建内置未来实例。
loop is an optional event loop instance.
创建内置任务实例。
loop
is an optional event loop instance. The rest of arguments are described in
loop.create_task()
description.
3.11 版改变： context 自变量被添加。
A third party task implementation should call the following functions to keep a task visible by
asyncio.get_tasks()
and
asyncio.current_task()
:
Register a new task as managed by asyncio .
从任务构造函数调用函数。
Unregister a task from asyncio internal structures.
The function should be called when a task is about to finish.
Switch the current task to the task 自变量。
Call the function just before executing a portion of embedded
协程
(
coroutine.send()
or
coroutine.throw()
).
Switch the current task back from
task
to
None
.
Call the function just after
coroutine.send()
or
coroutine.throw()
execution.
