Skip to content

Module 04: Async I/O Patterns

← Module 03 | Topic Home | Next → Module 05

Status Difficulty Time

Stub module — Full content to be generated. This file defines the scope and prerequisites so the topic roadmap is complete.

Overview

This module covers the practical I/O patterns you'll use daily in async Python programs: async HTTP clients with aiohttp, async file I/O with aiofiles, and the async iteration protocol — async context managers, async iterators, and async generators.

By the end of this module you will be able to replace every synchronous I/O call in a program with its async equivalent, write your own async context managers and generators, and compose them cleanly in production code.

Table of Contents

  1. Overview
  2. Prerequisites
  3. Objectives
  4. Theory
  5. Key Concepts
  6. Examples
  7. Common Pitfalls
  8. Cross-Links
  9. Summary

Prerequisites

  • Module 03: Tasks and Futures
  • Python context managers (with, __enter__, __exit__)
  • Python generators (yield, __iter__, __next__)

Objectives

By the end of this module, you will be able to:

  1. Make HTTP requests asynchronously using aiohttp.ClientSession
  2. Read and write files asynchronously using aiofiles
  3. Implement custom async context managers with async with / __aenter__ / __aexit__
  4. Implement async iterators with __aiter__ / __anext__
  5. Write async generators with async def + yield
  6. Consume async generators with async for
  7. Use contextlib.asynccontextmanager to write async context managers concisely

Theory

Full content to be generated. Topics to cover:

  • aiohttp.ClientSession — why sessions matter, connection pooling, base URL, headers
  • aiohttp request/response lifecycle: GET, POST, stream reading
  • aiofiles — async file reading and writing; why file I/O needs special treatment
  • The async with protocol: __aenter__ and __aexit__ as coroutines
  • The async for protocol: __aiter__ and __anext__
  • Async generators: async def + yield; pipeline composition
  • contextlib.asynccontextmanager decorator
  • httpx as a modern alternative to aiohttp

Key Concepts

To be filled in when this module is fully generated.

Examples

To be filled in when this module is fully generated.

Common Pitfalls

To be filled in when this module is fully generated.

  • [[async-python/modules/03_tasks-and-futures]] — prerequisite
  • [[async-python/modules/07_performance-patterns]] — connection pooling patterns build on session management introduced here
  • [[async-python/modules/08_async-databases]] — async database clients follow the same async with patterns introduced here

Summary

To be filled in when this module is fully generated.