Mastering Async in Flask | Python Web Development

Introduction

This lab will guide you through the process of using async and await in Flask, a popular Python web framework. You will learn how to define asynchronous views and handlers, understand the performance implications of using async code, and explore background tasks in Flask.

Note: You need to create the code file yourself and run it in the environment. You can preview the Flask service status on Web 5000.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%% flowchart RL flask(("`Flask`")) -.-> flask/CoreConceptsGroup(["`Core Concepts`"]) flask(("`Flask`")) -.-> flask/DevelopmentToolsGroup(["`Development Tools`"]) flask(("`Flask`")) -.-> flask/DataHandlingGroup(["`Data Handling`"]) flask/CoreConceptsGroup -.-> flask/application_object("`Application Object`") flask/DevelopmentToolsGroup -.-> flask/blueprint_objects("`Blueprint Objects`") flask/DataHandlingGroup -.-> flask/incoming_request_data("`Incoming Request Data`") flask/DataHandlingGroup -.-> flask/response_objects("`Response Objects`") flask/CoreConceptsGroup -.-> flask/useful_internals("`Useful Internals`") flask/DevelopmentToolsGroup -.-> flask/command_line_interface("`Command Line Interface`") subgraph Lab Skills flask/application_object -.-> lab-136110{{"`Using Async and Await in Flask`"}} flask/blueprint_objects -.-> lab-136110{{"`Using Async and Await in Flask`"}} flask/incoming_request_data -.-> lab-136110{{"`Using Async and Await in Flask`"}} flask/response_objects -.-> lab-136110{{"`Using Async and Await in Flask`"}} flask/useful_internals -.-> lab-136110{{"`Using Async and Await in Flask`"}} flask/command_line_interface -.-> lab-136110{{"`Using Async and Await in Flask`"}} end

Defining an Async View

In Flask, you can define views as asynchronous functions using the async def syntax. This allows you to use await to perform asynchronous operations within the view function.

@app.route("/get-data")
async def get_data():
    data = await async_db_query(...)
    return jsonify(data)

To run this code, save it in a Python file (e.g., app.py) and execute the file using the Flask development server:

flask run

Summary

In this lab, you learned how to use async and await in Flask to define asynchronous views and handlers. You also explored the performance implications of using async code, background tasks, and the use of Quart as an alternative to Flask for async-heavy codebases. Additionally, you learned about the compatibility of Flask extensions with async views and the possibility of using other event loops in Flask.

Using Async and Await in Flask

Introduction

Skills Graph

Defining an Async View

Summary

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