將標頭發送到客戶端Nodejs和Angular后無法設定標頭

我正在使用 Nodejs Express 開發登錄和注冊服務。郵遞員中的每個請求我都會收到相同的錯誤：

有趣的是，我在郵遞員中得到了回應（注冊、登錄我什至收到了我的 JWT 令牌，但每次請求后，如果不重新啟動終端中的服務，我什么也做不了）

我的 index.ts

 import express from "express";
 const https = require("https");
 import cors from "cors";
 import mongoose from "mongoose";
 const app = express();

 //import routes
 const usersRoute = require("./routes/users");

 //Middleware
 app.use(cors());
 app.use(express.urlencoded({ extended: false }));
 app.use(express.json());

 //route midddlewares
 app.use("/api/users", usersRoute);

 //connect to db
 mongoose
   .connect("mongodb://localhost:27017/loginregister")
   .then(() => {
     console.log("connected to database");
   })
   .catch(() => {
     console.log("connection failed!");
   });
 const PORT = 3000;
 app.listen(PORT, () => console.log(`Server up and running on port ${PORT}`));

還有我的 users.ts

 import express from "express";
 const router = express.Router();
 const User = require("../models/User");

 const {
   registerValidation,
   loginValidation,
 } = require("../middleware/validation");
 const bcrypt = require("bcryptjs");
 const jwt = require("jsonwebtoken");
 const secretKey = "f43g34gergeerg";
 const verifyToken = require("../middleware/verifyToken");

 //REGISTER user
 router.post("/register", async (req, res) => {
   //VALIDATE DATA from Joi, before register
   const { error } = registerValidation(req.body);
   if (error) return res.status(400).send(error.details[0].message);

   //check if user is alredy in database
   const emailExist = await User.findOne({ email: req.body.email });
   if (emailExist) return res.status(400).send("Email already exists");

   //encrypt password z bcryptjs modulom
   const salt = await bcrypt.genSalt(10);
   const hashPassword = await bcrypt.hash(req.body.password, salt);

   //create new user
   const user = new User({
     email: req.body.email,
     password: hashPassword,
   });
   try {
     //save new user
     const savedUser = await user.save();
     //res.json(savedUser);
     res.json({ user: user._id });
   } catch (err) {
     res.json({ message: err });
   }
 });

   //LOGIN
   router.post("/login", async (req, res) => {
    const { error } = loginValidation(req.body);
    if (error) return res.status(400).send(error.details[0].message);

   //check if email exists
   const user = await User.findOne({ email: req.body.email });
   if (!user) return res.status(400).send("Email doesn't exist");

   //password is correct 
   const validPass = await bcrypt.compare(req.body.password, user.password);
   if (!validPass) return res.status(400).send("Invalid password");

   //create and send a json web token
   const token = jwt.sign({ _id: user._id }, secretKey, { expiresIn: "1h" });
   res.header("auth-token", token).send(token);
   res.send("Logged in!");
 });

 module.exports = router;

檔案：verifyToken.ts

   const jwt = require("jsonwebtoken");
   const secretKey = "f43g34gergeerg";

   module.exports = (req: any, res: any, next: any) => {
     const token = req.header("auth-token");
     if (!token) return res.status(401).send("Access denied");

     try {
       const verified = jwt.verify(token, secretKey);
       req.user = verified;
       next();
     } catch (err) {
       res.status(400).send("Invalid token");
     }
   };

我的前端（Angular）代碼：login.component.ts

export class LoginComponent implements OnInit {
  email: string = '';
  password: string = '';

  constructor(public authService: AuthService, private router: Router) {}

  ngOnInit(): void {}

  onLogin(form: NgForm) {
    if (form.invalid) {
      return;
    }
    this.authService.login(form.value.email, form.value.password);
    console.log(form.value);
  }
}

auth.service.ts 檔案

   export class AuthService {
   constructor(private http: HttpClient) {}

   login(email: string, password: string) {
     const user: User = { email: email, password: password };
     this.http
       .post('http://localhost:3000/api/users/login', user)
       .subscribe((response: any) => {
         console.log(response);
       });
   }
 }

網路中的錯誤是：

已解決： 終端中的第一個錯誤（發送到客戶端后無法設定標頭）已通過 Shivam Sood 接受的答案解決），并且通過定義 responseType 解決了我瀏覽器中錯誤選項卡中的第二個錯誤：'text ' 在我的 auth.service.ts 檔案中的 http.post() 請求中

uj5u.com熱心網友回復：

錯誤來自您login路線中的這一行

res.header("auth-token", token).send(token);
res.send("Logged in!");

您發送回應兩次res.send()

您必須洗掉res.send("Logged in!");才能解決問題。

更新

我懷疑角度的問題在于，默認情況下，角度 HTTP 需要 JSON 資料，但您從后端發送的資料是文本。這就是決議失敗的原因。

你可以更新res.send到

res.header("auth-token", token).json({token});

標籤：节点.js 有角度的 表示

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