Flutter应用无法连接Node.js服务器，注册数据无法同步至MongoDB

我正在尝试将Flutter应用连接至Node.js服务器，应用的注册页面可收集用户的用户名、密码和邮箱信息，需通过Node.js服务器将数据同步至MongoDB，但目前出现连接失败问题。

Node.js服务器代码 #

const express = require('express');
const mongoose = require('mongoose');
const bodyParser = require('body-parser');

const app = express();
const port = 5555;

// Use body-parser middleware to parse JSON request bodies
app.use(bodyParser.json());

// Connect to MongoDB (Replace with your MongoDB connection string)
mongoose.connect('mongodb+srv://panchalmeet316:meetrocks@cluster0.vb8df.mongodb.net/INSIGHTIFY?retryWrites=true&w=majority&appName=Cluster0')
  .then(() => {
    console.log('Connected to MongoDB');
  })
  .catch((err) => {
    console.error('Error connecting to MongoDB:', err.message);
  });

// Define a Mongoose schema for users
const userSchema = new mongoose.Schema({
  username: { type: String, required: true },
  password: { type: String, required: true },
  email: { type: String, required: true, unique: true },
});

// Create a Mongoose model from the schema
const User = mongoose.model('User', userSchema);

// Define an API endpoint for user registration
app.post('/register', async (req, res) => {
  const { username, password, email } = req.body;

  // Basic validation (you can expand this as needed)
  if (!username || !email || !password) {
    return res.status(400).send('All fields are required');
  }

  try {
    // Create a new user instance
    const newUser = new User({ username, password, email });

    // Save the user to the database
    await newUser.save();

    res.status(201).send('User registered successfully');
  } catch (error) {
    if (error.code === 11000) {
      // Duplicate email error
      res.status(400).send('Email is already registered');
    } else {
      res.status(500).send('Server error');
    }
  }
});

// Define an API endpoint for user login
app.post('/login', async (req, res) => {
  const { username, password } = req.body;

  try {
    const user = await User.findOne({ username });

    if (!user) {
      return res.status(401).send('Invalid username or password');
    }

    const isPasswordValid = await bcrypt.compare(password, user.password);

    if (!isPasswordValid) {
      return res.status(401).send('Invalid username or password');
    }

    // Generate a session token or JWT
    // const token = jwt.sign({ userId: user._id }, 'your_secret_key');

    // res.status(200).json({ token });
  } catch (error) {
    res.status(500).send('Server error');
  }
});

// Start the server
app.listen(() => {
  console.log(`Server is running on http://192.168.47.1:${port}`);
});

Flutter客户端代码 #

Future<void> registerUser() async {
  var userData = {
    'username': nameController.text,
    'password': passwordController.text,
    'email': emailController.text, // Use singular 'email' instead of 'emails'
  };

  var jsonData = jsonEncode(userData);

  try {
    var response = await http.post(
      Uri.parse('http://192.168.0.102:5555/register'),
      headers: {
        'Content-Type': 'application/json',
      },
      body: jsonData,
    );

    if (response.statusCode == 200) {
      print('User registered successfully');
    } else {
      // Handle other status codes
      switch (response.statusCode) {
        case 400:
          print('Registration failed: Bad request (invalid data)');
          break;
        case 409:
          print('Registration failed: Email already registered');
          break;
        case 500:
          print('Registration failed: Internal server error');
          break;
        default:
          print('Registration failed: Unknown error (code: ${response.statusCode})');
      }
      throw Exception('Registration failed'); // Throw an exception for further handling
    }
  } on Exception catch (e) {
    print('An error occurred: $e');
    // Display user-friendly error message in your app UI
  }
}

已尝试的解决措施 #

• 咨询Gemini和ChatGPT，确认代码逻辑无问题
• 关闭防火墙
• 检查网络配置

问题仍未解决，陷入僵局。

内容的提问来源于stack exchange，提问作者meet panchal