18. Interprocess Communication and Networking
*********************************************

The modules described in this chapter provide mechanisms for different
processes to communicate.

某些模块仅适用于同一台机器上的两个进程，例如 "signal" 和 "mmap" 。 其
他模块支持两个或多个进程可用于跨机器通信的网络协议。

本章中描述的模块列表是：

* 18.1. "socket" --- 底层网络接口

  * 18.1.1. 套接字协议族

  * 18.1.2. Module contents

    * 18.1.2.1. 异常

    * 18.1.2.2. 常数

    * 18.1.2.3. 函数

      * 18.1.2.3.1. Creating sockets

      * 18.1.2.3.2. 其他功能

  * 18.1.3. Socket Objects

  * 18.1.4. Notes on socket timeouts

    * 18.1.4.1. Timeouts and the "connect" method

    * 18.1.4.2. Timeouts and the "accept" method

  * 18.1.5. 示例

* 18.2. "ssl" --- TLS/SSL wrapper for socket objects

  * 18.2.1. Functions, Constants, and Exceptions

    * 18.2.1.1. Socket creation

    * 18.2.1.2. Context creation

    * 18.2.1.3. Random generation

    * 18.2.1.4. Certificate handling

    * 18.2.1.5. 常数

  * 18.2.2. SSL Sockets

  * 18.2.3. SSL Contexts

  * 18.2.4. Certificates

    * 18.2.4.1. Certificate chains

    * 18.2.4.2. CA certificates

    * 18.2.4.3. Combined key and certificate

    * 18.2.4.4. Self-signed certificates

  * 18.2.5. 示例

    * 18.2.5.1. Testing for SSL support

    * 18.2.5.2. Client-side operation

    * 18.2.5.3. Server-side operation

  * 18.2.6. Notes on non-blocking sockets

  * 18.2.7. Memory BIO Support

  * 18.2.8. SSL session

  * 18.2.9. Security considerations

    * 18.2.9.1. Best defaults

    * 18.2.9.2. Manual settings

      * 18.2.9.2.1. Verifying certificates

      * 18.2.9.2.2. Protocol versions

      * 18.2.9.2.3. Cipher selection

    * 18.2.9.3. Multi-processing

  * 18.2.10. LibreSSL support

* 18.3. "select" --- Waiting for I/O completion

  * 18.3.1. "/dev/poll" Polling Objects

  * 18.3.2. Edge and Level Trigger Polling (epoll) Objects

  * 18.3.3. Polling Objects

  * 18.3.4. Kqueue Objects

  * 18.3.5. Kevent Objects

* 18.4. "selectors" --- 高级 I/O 复用库

  * 18.4.1. 概述

  * 18.4.2. 类

  * 18.4.3. 示例

* 18.5. "asyncio" --- Asynchronous I/O, event loop, coroutines and
  tasks

  * 18.5.1. Base Event Loop

    * 18.5.1.1. Run an event loop

    * 18.5.1.2. Calls

    * 18.5.1.3. Delayed calls

    * 18.5.1.4. Futures

    * 18.5.1.5. Tasks

    * 18.5.1.6. Creating connections

    * 18.5.1.7. Creating listening connections

    * 18.5.1.8. Watch file descriptors

    * 18.5.1.9. Low-level socket operations

    * 18.5.1.10. Resolve host name

    * 18.5.1.11. Connect pipes

    * 18.5.1.12. UNIX signals

    * 18.5.1.13. Executor

    * 18.5.1.14. 错误处理API

    * 18.5.1.15. Debug mode

    * 18.5.1.16. Server

    * 18.5.1.17. Handle

    * 18.5.1.18. Event loop examples

      * 18.5.1.18.1. call_soon() 的 Hello World 示例。

      * 18.5.1.18.2. 使用 call_later() 来展示当前的日期

      * 18.5.1.18.3. 监控一个文件描述符的读事件

      * 18.5.1.18.4. 为SIGINT和SIGTERM设置信号处理器

  * 18.5.2. 事件循环

    * 18.5.2.1. 事件循环函数

    * 18.5.2.2. 可用的事件循环

    * 18.5.2.3. 平台支持

      * 18.5.2.3.1. Windows

      * 18.5.2.3.2. Mac OS X

    * 18.5.2.4. 事件循环策略和默认策略

    * 18.5.2.5. 事件循环策略接口

    * 18.5.2.6. 访问全局循环策略

    * 18.5.2.7. 自定义事件循环策略

  * 18.5.3. Tasks and coroutines

    * 18.5.3.1. 协程

      * 18.5.3.1.1. Example: Hello World coroutine

      * 18.5.3.1.2. Example: Coroutine displaying the current date

      * 18.5.3.1.3. Example: Chain coroutines

    * 18.5.3.2. InvalidStateError

    * 18.5.3.3. TimeoutError

    * 18.5.3.4. Future

      * 18.5.3.4.1. Example: Future with run_until_complete()

      * 18.5.3.4.2. Example: Future with run_forever()

    * 18.5.3.5. Task

      * 18.5.3.5.1. Example: Parallel execution of tasks

    * 18.5.3.6. Task functions

  * 18.5.4. Transports and protocols (callback based API)

    * 18.5.4.1. 传输

      * 18.5.4.1.1. BaseTransport

      * 18.5.4.1.2. ReadTransport

      * 18.5.4.1.3. WriteTransport

      * 18.5.4.1.4. DatagramTransport

      * 18.5.4.1.5. BaseSubprocessTransport

    * 18.5.4.2. 协议

      * 18.5.4.2.1. Protocol classes

      * 18.5.4.2.2. Connection callbacks

      * 18.5.4.2.3. Streaming protocols

      * 18.5.4.2.4. Datagram protocols

      * 18.5.4.2.5. Flow control callbacks

      * 18.5.4.2.6. Coroutines and protocols

    * 18.5.4.3. Protocol examples

      * 18.5.4.3.1. TCP echo client protocol

      * 18.5.4.3.2. TCP echo server protocol

      * 18.5.4.3.3. UDP echo client protocol

      * 18.5.4.3.4. UDP echo server protocol

      * 18.5.4.3.5. Register an open socket to wait for data using a
        protocol

  * 18.5.5. Streams (coroutine based API)

    * 18.5.5.1. Stream functions

    * 18.5.5.2. StreamReader

    * 18.5.5.3. StreamWriter

    * 18.5.5.4. StreamReaderProtocol

    * 18.5.5.5. IncompleteReadError

    * 18.5.5.6. LimitOverrunError

    * 18.5.5.7. Stream examples

      * 18.5.5.7.1. TCP echo client using streams

      * 18.5.5.7.2. TCP echo server using streams

      * 18.5.5.7.3. Get HTTP headers

      * 18.5.5.7.4. Register an open socket to wait for data using
        streams

  * 18.5.6. Subprocess

    * 18.5.6.1. Windows event loop

    * 18.5.6.2. Create a subprocess: high-level API using Process

    * 18.5.6.3. Create a subprocess: low-level API using
      subprocess.Popen

    * 18.5.6.4. 常数

    * 18.5.6.5. Process

    * 18.5.6.6. Subprocess and threads

    * 18.5.6.7. Subprocess examples

      * 18.5.6.7.1. Subprocess using transport and protocol

      * 18.5.6.7.2. Subprocess using streams

  * 18.5.7. Synchronization primitives

    * 18.5.7.1. Locks

      * 18.5.7.1.1. Lock

      * 18.5.7.1.2. Event

      * 18.5.7.1.3. Condition

    * 18.5.7.2. Semaphores

      * 18.5.7.2.1. Semaphore

      * 18.5.7.2.2. BoundedSemaphore

  * 18.5.8. 队列集

    * 18.5.8.1. 队列

    * 18.5.8.2. PriorityQueue

    * 18.5.8.3. LifoQueue

      * 18.5.8.3.1. 异常

  * 18.5.9. Develop with asyncio

    * 18.5.9.1. Debug mode of asyncio

    * 18.5.9.2. Cancellation

    * 18.5.9.3. Concurrency and multithreading

    * 18.5.9.4. Handle blocking functions correctly

    * 18.5.9.5. 日志

    * 18.5.9.6. Detect coroutine objects never scheduled

    * 18.5.9.7. Detect exceptions never consumed

    * 18.5.9.8. Chain coroutines correctly

    * 18.5.9.9. Pending task destroyed

    * 18.5.9.10. Close transports and event loops

* 18.6. "asyncore" --- 异步socket处理器

  * 18.6.1. asyncore Example basic HTTP client

  * 18.6.2. asyncore Example basic echo server

* 18.7. "asynchat" --- 异步 socket 指令/响应 处理器

  * 18.7.1. asynchat Example

* 18.8. "signal" --- Set handlers for asynchronous events

  * 18.8.1. General rules

    * 18.8.1.1. Execution of Python signal handlers

    * 18.8.1.2. Signals and threads

  * 18.8.2. Module contents

  * 18.8.3. 示例

* 18.9. "mmap" --- 内存映射文件支持
