使用Express、Passport、Jwt构建认证API时POST请求遇404错误求助

Hey there! Let's dig into why you're getting that frustrating 404 error when sending POST requests to your auth API. Since you're working directly with SQL instead of a User model, there are a few key areas we need to check first—most 404s here boil down to routing mismatches or middleware order issues.

Common Causes & Fixes #

1. Routing Path Mismatch (Most Likely Culprit)

First, double-check that your request URL exactly matches the route you defined:

• If your routes.js has router.post('/auth/login', ...), and you mounted the router in app.js with app.use('/api', require('./routes')), your full request path should be POST /api/auth/login—not /auth/login or /api/login.
• Watch out for typos, trailing slashes, or capitalization differences (Express routes are case-sensitive!).
• Confirm you’re using router.post() (not get) for the login endpoint—mixing these up will definitely throw a 404.

2. Middleware Order is Wrong

Express executes middleware in the order you define them, so misplacing Passport or body-parsing middleware can break your routes:

• Make sure you’re parsing request bodies before mounting Passport or your routes:

  // app.js
  app.use(express.json()); // Parses JSON request bodies
  app.use(express.urlencoded({ extended: true })); // Parses form-data
  
  // Initialize Passport NEXT
  const passport = require('./passport');
  app.use(passport.initialize());
  
  // THEN mount your routes
  app.use('/api', require('./routes'));
  

• If you accidentally mount routes before Passport or body-parser, your auth handler won’t have access to req.body (for username/password) or Passport’s authentication methods.

3. Passport Local Strategy Isn’t Properly Registered

Even if your routes are correct, a misconfigured Passport strategy can cause silent failures (though this usually throws a 401, not 404—worth checking anyway):

• In passport.js, ensure you’ve registered the local strategy correctly, with a valid SQL query to fetch users:

  const LocalStrategy = require('passport-local').Strategy;
  const bcrypt = require('bcrypt');
  const db = require('./your-mariadb-connection'); // Your DB connection
  
  passport.use(new LocalStrategy((username, password, done) => {
    // Fetch user from MariaDB
    const query = 'SELECT id, username, password FROM users WHERE username = ?';
    db.query(query, [username], (err, results) => {
      if (err) return done(err); // Handle DB errors
      if (!results.length) return done(null, false, { message: 'User not found' });
  
      // Verify password hash
      const isValid = bcrypt.compareSync(password, results[0].password);
      if (!isValid) return done(null, false, { message: 'Incorrect password' });
  
      // Return user data (without password!)
      const user = { id: results[0].id, username: results[0].username };
      return done(null, user);
    });
  }));
  

• If you forget to call passport.use() with the LocalStrategy, Passport won’t recognize the local authentication method in your routes.

4. Route Handler Missing Passport Authentication

Make sure your login route is actually using Passport’s authenticate middleware:

// routes.js
const jwt = require('jsonwebtoken');

router.post('/auth/login', passport.authenticate('local', { session: false }), (req, res) => {
  // Generate JWT token once authenticated
  const token = jwt.sign(
    { id: req.user.id, username: req.user.username },
    process.env.JWT_SECRET,
    { expiresIn: '1h' }
  );
  res.json({ success: true, token });
});

• Omitting passport.authenticate('local', ...) here means the route won’t trigger your auth logic, but it shouldn’t throw a 404—unless the route itself is misdefined.

Next Steps to Debug #

If none of the above fixes work, share snippets of:

• The middleware/routing section of app.js
• Your full login route in routes.js
• Your Passport strategy configuration in passport.js

That’ll help pinpoint exactly where the disconnect is!

内容的提问来源于stack exchange，提问作者Vana