javascript - `uri`参数到 `openUri()`必须是字符串，得到 "undefined"

Question

我对此进行了很多搜索，但没有一个能帮助我。

当我运行我的项目时，出现此错误:

/home/ali/Desktop/personalitytest-backend/node_modules/mongoose/lib/connection.js:428 throw new MongooseError('The uri parameter to openUri() must be a ' + ^ MongooseError: The uri parameter to openUri() must be a string, got "undefined". Make sure the first parameter to mongoose.connect() or mongoose.createConnection() is a string.

我的 index.js 文件:

const express = require('express'),
  app = express(),
  mongoose = require('mongoose'),
  rateLimit = new require('express-rate-limit')({
    windowMs: 1000 * 60 * 10,
    max: 500,
    handler: (req, res) => {
      res.json({
        data: 'Your request was too much, please try again in 10 minutes later.',
        status: 'error'
      })
    }
  });
const Application = new class {
  constructor() {
    this.setConfig();
    this.setupDB();
    this.setRouters();
    this.setupExpress();
  }
  setConfig() {
    require('dotenv').config();
    app.use(require('helmet')());
    app.use(express.json());
  }
  setupDB() {
    mongoose.Promise = global.Promise;
    mongoose.connect(process.env.DATABASE_URL, { useNewUrlParser: true, useCreateIndex: true });
  }
  setRouters() {
    app.use('/', require('./routes'));
  }
  setupExpress() {
    app.listen(process.env.PORT, () => console.log(`Listening on port ${process.env.PORT}.`));
    // app.listen(process.env.PORT, process.env.IP, () => console.log(`Listening on port ${process.env.PORT}.`));
  }
}

我的 .env 文件:

PORT=3000
DATABASE_URL=mongodb://localhost:27017/PersonalityTest
JWT_SECRETKEY=asfdawetq312etr%!@$qe

如果我在mongoose.connect 方法中简单地写数据库url，不会有错误。

例如，这没有错误:

mongoose.connect("mongodb://localhost:27017/PersonalityTest", { useNewUrlParser: true, useCreateIndex: true });

Answer 1

要读取 .env 文件，您需要安装可以读取该文件的东西，例如 dotenv 包

npm install dotenv --save

那你require that package in your code

require('dotenv').config();

根据 dotenv 文档你应该这样做

As early as possible in your application, require and configure dotenv.

接下来您可能需要在您的 DATABASE_URL 值周围添加双引号

DATABASE_URL="mongodb://localhost:27017/PersonalityTest"