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根据 request.method 分支处理逻辑

在 GET 时提供表单，并在 POST 时处理表单

根据 request.method 分支处理逻辑 是 CoddyKit 上的免费 Flask Academy 课时。这是第 2 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Flask Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Flask Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

One Route, Two Jobs

A route that accepts both GET and POST often needs to behave differently for each. You handle that by checking which verb arrived.

The request Object

Flask gives you a global request object that describes the incoming call. Import it once and use it inside any view.

from flask import request

Read request.method

The attribute request.method holds the verb of the current call as a string like "GET" or "POST".

if request.method == "POST":
    print("handling a form")

Branch on the Verb

Wrap your logic in an if that checks request.method. One branch shows a form, the other processes the submitted data.

The Classic Form Pattern

The most common shape is: on GET render the empty form, and on POST read the answers and act on them.

@app.route("/contact", methods=["GET", "POST"])
def contact():
    if request.method == "POST":
        return "saved"
    return "show form"

GET Should Not Change Data

Keep the GET branch read-only. A GET request must never create or modify records, since browsers may repeat it freely.

POST Does the Work

Put writes, saves, and side effects in the POST branch. That keeps mutations tied to a deliberate submission.

Compare Strings Exactly

Always compare against the exact uppercase value. request.method is "POST", never "post", so a lowercase check will silently fail.

An else for the Fallthrough

Treat the GET case as the natural else. Return the form view when the method is not POST so the page always renders.

Skip Checks Flask Handles

You never test for a verb you did not allow. Flask blocks unlisted methods before your code runs, so only listed verbs arrive.

Keep Branches Small

If each branch grows large, call helper functions from the if. The view stays a clean dispatcher between GET and POST.

Quick Check

Pick the branch that should change data.

Recap

Use request.method to branch: render the form on GET, process and save on POST. Keep GET read-only and POST for changes. Great work! 🙌

常见问题解答

「根据 request.method 分支处理逻辑」课时是免费的吗？

是的 — 「根据 request.method 分支处理逻辑」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Flask Academy 课程的其余内容，请升级到 CoddyKit PRO。 Flask Academy 课程共包含 4 节课。

「根据 request.method 分支处理逻辑」这节课中我会学到什么？

在 GET 时提供表单，并在 POST 时处理表单你通过在浏览器中直接运行的动手代码来练习 Flask Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Flask Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Flask Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 2 节课，共 4 节。

「根据 request.method 分支处理逻辑」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Flask Academy 课中编写并运行代码吗？

能。每节 Flask Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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