Node.js Backend Development Bootcamp · 课时

用户注册与登录

构建用户注册和登录功能，包括密码哈希处理与凭据安全存储。

用户注册与登录 是 CoddyKit 上的免费 Node.js Backend Development Bootcamp 课时。这是第 1 节课，共 6 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 Node.js Backend Development Bootcamp 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Node.js Backend Development Bootcamp 课程共包含 6 节课。

本课时的部分内容尚未翻译，以英文显示。

Welcome to User Authentication

User authentication is how we verify who a user is. It's a critical part of almost any application that handles personal data or restricted features.

Why it matters: Protects user accounts and sensitive information.
What we'll cover: Building registration and login flows from scratch.

The User Registration Flow

Registering a new user involves several steps to create a new account:

User provides credentials (e.g., username, password, email).
Input data is validated (e.g., strong password, unique email).
The password is hashed for security.
New user data (including the hashed password) is saved to the database.

Why Hash Passwords?

Storing passwords in plain text is a huge security risk! If your database is breached, all user passwords would be exposed.

Hashing transforms a password into a fixed-size, unreadable string. It's a one-way process, meaning you can't easily get the original password back from the hash.

We use libraries like bcrypt in Node.js for robust password hashing, which also adds a 'salt' to prevent common attacks.

Hashing Passwords with bcrypt

bcrypt is a popular library for securely hashing passwords. It's computationally intensive, making brute-force attacks harder.

Try running this example to see a password hashed:

const bcrypt = require('bcrypt');

const password = "mySecretP@ssword";
const saltRounds = 10; // Cost factor for hashing (higher is slower/more secure)

async function hashPassword() {
  try {
    const hashedPassword = await bcrypt.hash(password, saltRounds);
    console.log("Original: " + password);
    console.log("Hashed: " + hashedPassword);
  } catch (error) {
    console.error("Error hashing:" + error.message);
  }
}

hashPassword();

Storing Hashed Credentials

After hashing, only the hashed password should be stored in your database, along with other user details like their email or username.

NEVER store plain-text passwords.
The hash is unique for each password, even if the original passwords are the same (thanks to salting).
This hash is what you'll use for comparison during login.

The User Login Flow

When a user tries to log in, your application follows these steps:

User provides their username/email and password.
Application retrieves the user's record (including their stored hashed password) from the database based on the username/email.
The provided password is hashed and compared against the stored hash.
If they match, the user is authenticated, and a session or token is created.

Verifying Passwords with bcrypt

To check if a user's provided password matches the stored hash, we use bcrypt.compare(). It performs the hashing and comparison securely.

Run this code to see password comparison in action:

const bcrypt = require('bcrypt');

// This hash would typically come from your database
const storedHash = "$2b$10$w090/qB2k6n0Y7o8p9q.u.0Z1X2Y3Z4A5B6C7D8E9F0G1H2I3J4K5L6M7N8O9P0Q1R"; 

const passwordAttempt = "mySecretP@ssword";
const wrongAttempt = "incorrectPassword";

async function comparePasswords() {
  try {
    const isMatch = await bcrypt.compare(passwordAttempt, storedHash);
    console.log(`'${passwordAttempt}' matches: ${isMatch}`);

    const isWrongMatch = await bcrypt.compare(wrongAttempt, storedHash);
    console.log(`'${wrongAttempt}' matches: ${isWrongMatch}`);
  } catch (error) {
    console.error("Error comparing:" + error.message);
  }
}

comparePasswords();

Secure Credential Storage Practices

Beyond just hashing passwords, other credentials need protection:

API Keys & Database URLs: Store these in environment variables (e.g., .env files), not directly in your code.
Sensitive User Data: Encrypt any highly sensitive data at rest in your database.
Regular Updates: Keep your hashing libraries and dependencies up-to-date.

Handling Authentication Errors

When registration or login fails, provide helpful but generic error messages to the user. This prevents revealing too much information to potential attackers.

Instead of 'User not found', say 'Invalid credentials'.
Instead of 'Password incorrect', also say 'Invalid credentials'.
Log detailed errors on the server side for debugging, but don't expose them to the client.

Quick Check: Password Hashing

Test your understanding of why password hashing is essential for security.

Recap: Registration & Login

In this lesson, you learned the fundamental steps for user registration and login:

We covered the importance of password hashing using bcrypt to protect sensitive user data.
You saw how to implement both the hashing for registration and the comparison for login.
We also touched on best practices for secure credential storage and handling authentication errors gracefully.

Next, we'll dive into implementing stateless authentication using JSON Web Tokens (JWTs).

常见问题解答

「用户注册与登录」课时是免费的吗？

是的 — 「用户注册与登录」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 Node.js Backend Development Bootcamp 课程的其余内容，请升级到 CoddyKit PRO。 Node.js Backend Development Bootcamp 课程共包含 6 节课。

「用户注册与登录」这节课中我会学到什么？

构建用户注册和登录功能，包括密码哈希处理与凭据安全存储。你通过在浏览器中直接运行的动手代码来练习 Node.js Backend Development Bootcamp，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 Node.js Backend Development Bootcamp 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Node.js Backend Development Bootcamp 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 1 节课，共 6 节。

「用户注册与登录」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 Node.js Backend Development Bootcamp 课中编写并运行代码吗？

能。每节 Node.js Backend Development Bootcamp 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。

此课程中的所有课时

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