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Bearer 令牌与请求头

要求每个请求提供访问令牌并读取它。

Bearer 令牌与请求头 是 CoddyKit 上的免费 MCP 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 MCP Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 MCP 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。

What a Bearer Token Is

A bearer token is a secret string that means "whoever holds this is allowed in." The server trusts the holder, no password needed per call. 🎟️

The Authorization Header

Clients send the token in the HTTP Authorization header so it rides along with every request automatically.

The Bearer Prefix

The header value starts with the word Bearer, a space, then the token. That prefix tells the server which auth scheme is in use.

GET /mcp HTTP/1.1
Authorization: Bearer sk-7f3a9c2e8b1d4a6f

Reading the Header on the Server

Your MCP server pulls the Authorization value off the incoming request before handling the JSON-RPC body.

auth = request.headers.get("Authorization", "")
token = auth.removeprefix("Bearer ").strip()

Compare, Then Decide

The server checks the token against what it expects. A match lets the request through; anything else is rejected.

if token != EXPECTED_TOKEN:
    raise HTTPException(status_code=401)

Use Constant-Time Comparison

Plain equality can leak timing hints. Use a constant-time compare so attackers cannot guess the token character by character.

import hmac
ok = hmac.compare_digest(token, EXPECTED_TOKEN)

401 Means Not Authenticated

Return 401 Unauthorized when the token is missing or invalid. It signals the caller to supply valid credentials.

403 Means Not Allowed

Use 403 Forbidden when the caller is known but lacks permission for that action. It is a different answer than 401.

Keep Tokens Out of URLs

Never put the token in the query string. URLs land in logs and browser history, so the header is the safer home for secrets.

Store Secrets in the Environment

Read the expected token from an environment variable, never hardcoded in source. That keeps it out of your version control.

import os
EXPECTED_TOKEN = os.environ["MCP_TOKEN"]

Rotate When in Doubt

If a token might be exposed, issue a new one and retire the old. Rotation limits how long a leaked secret stays useful.

Quick Check

Spot the correct header format.

Recap: One Header, One Check

Send the secret as Bearer in the Authorization header, compare it safely, and answer 401 when it fails. Simple and solid. ✅

常见问题解答

「Bearer 令牌与请求头」课时是免费的吗？

是的 — 「Bearer 令牌与请求头」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 MCP Academy 课程的其余内容，请升级到 CoddyKit PRO。 MCP Academy 课程共包含 4 节课。

「Bearer 令牌与请求头」这节课中我会学到什么？

要求每个请求提供访问令牌并读取它。你通过在浏览器中直接运行的动手代码来练习 MCP 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 MCP Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 MCP 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。

「Bearer 令牌与请求头」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 MCP Academy 课中编写并运行代码吗？

能。每节 MCP 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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