Why I am having undefined value on my mongoose connection?-CodePudding

just a beginner in nodeJS, and I encountered this problem.

Server is running on http://localhost:8080
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.
    at Connection.openUri (C:\SimpleChatApp\node_modules\mongoose\lib\connection.js:694:11)
    at C:\SimpleChatApp\node_modules\mongoose\lib\index.js:380:10
    at C:\SimpleChatApp\node_modules\mongoose\lib\helpers\promiseOrCallback.js:41:5
    at new Promise (<anonymous>)
    at promiseOrCallback (C:\SimpleChatApp\node_modules\mongoose\lib\helpers\promiseOrCallback.js:40:10)
    at Mongoose._promiseOrCallback (C:\SimpleChatApp\node_modules\mongoose\lib\index.js:1225:10)
    at Mongoose.connect (C:\SimpleChatApp\node_modules\mongoose\lib\index.js:379:20)
    at connectDB (C:\SimpleChatApp\server\database\connection.js:4:36)
    at Object.<anonymous> (C:\SimpleChatApp\server.js:14:1)
    at Module._compile (node:internal/modules/cjs/loader:1120:14)
[nodemon] app crashed - waiting for file changes before starting...

this is my server.js

const express = require('express');
const dotenv = require('dotenv');
const morgan = require('morgan');
const bodyparser = require('body-parser');
const path = require('path');
const connectDB = require('./server/database/connection');

const app = express();

const PORT = process.env.PORT||8080

app.use(morgan('tiny'));

connectDB();

app.use(bodyparser.urlencoded({ extended: true }));

app.set("view engine", "ejs");

app.listen(PORT, () => { console.log('Server is running on http://localhost:${PORT}') });

and here is my connection.js

const mongoose = require('mongoose');
const connectDB = async () => {
    try{
        const con = await mongoose.connect(process.env.MONGO_URI, {
            useNewUrlParser: true,
            useUnifiedTopology: true,
            useFindAndModify: false,
            useCreateIndex: true
        })
        console.log('Database Connected: ${con.connection.host}');
    }catch(err){
        console.log(err);
        process.exit(1);
    }
}

module.exports = connectDB

and my env file

PORT=3000

MONGO_URI=mongodb srv://admin:[email protected]/mydb?retryWrites=true&w=majority

hope you guys can help me. I am really stuck with this. Already tried to look for answers to the problems here in StackOverflow but it seems like not working with me or I am doing it wrong. Thank you in advance!

CodePudding user response：

You have to make a config connection to your .env file. Try a module like dotenv

From the dotenv docs:

require('dotenv').config()
console.log(process.env) // remove this after you've confirmed it working

Also, the console.log of the 'Server is running on localhost:${PORT}'" is incorrect syntax. it should be a string template with back ticks:

console.log(`Server is running on http://localhost:${PORT}`)

Same goes for the console.log in your connection file

CodePudding user response：

It seems like the connection string isn't being read from your .env file, hence the undefined error.

You may have forgotten to call the .config() after your dotenv import.

Wherever you use these environment variables, be sure to include this line above it.

require("dotenv").config();

CodePudding user response：

Do you need "export" on your env settings?