Node.js cors origins from app deployed on heroku-CodePudding

I've deployed my node.js app on heroku and now I'm trying to connect to this from my localhost:3000, but I've got this error:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://blogs-backend-nodejs.herokuapp.com/api/user/login. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). Status code: 503.

here below my Node app.js code:


import express from 'express';
import mongoose from 'mongoose';
import blogRouter from './routes/blog-routes';
import router from './routes/user-routes';
import cors from 'cors';

const port = process.env.PORT || 5000
const app = express();

const whitelist = ["http://localhost:3000"]

const corsOptions = {
    origin: function (origin, callback) {
        if (!origin || whitelist.indexOf(origin) !== -1) {
            callback(null, true)
        } else {
            callback(new Error("Not allowed by CORS"))
        }
    },
    credentials: true,
}

app.use(cors(corsOptions));

//Middlewares
app.use(express.json());

app.use("/api/user", router);
app.use("/api/blog", blogRouter);
mongoose.connect(
    'mongodb srv://Denys:[email protected]/?retryWrites=true&w=majority'
)
    .then(() => app.listen(port))
    .then(() =>
        console.log('Connected')
    )
    .catch((err) => console.log(err));

As you see I have mongodb connected to my node.js app. I've allowed localhost:3000 origin, but still the same error from backend.

What is wrong? I'll be very appreciate for some help.

Thanks in advance!

CodePudding user response：

You can try this.

import express from 'express';
import mongoose from 'mongoose';
import blogRouter from './routes/blog-routes';
import router from './routes/user-routes';
import cors from 'cors';

const port = process.env.PORT || 5000
const app = express();


let corsOrigins=[];

if(process.env.REQUEST_ORIGIN){
    corsOrigins=[process.env.REQUEST_ORIGIN];
}
else{
    corsOrigins=["http://localhost:3000"];
}
const corsOptions = {
    origin: corsOrigins,
    methods:['GET','POST'],
    allowedHeaders: ['Content-Type', 'Authorization']   
};

app.use(cors(corsOptions));

//Middlewares
app.use(express.json());

app.use("/api/user", router);
app.use("/api/blog", blogRouter);
mongoose.connect(
    'mongodb srv://Denys:[email protected]/?retryWrites=true&w=majority'
)
    .then(() => app.listen(port))
    .then(() =>
        console.log('Connected')
    )
    .catch((err) => console.log(err));

I hope your error will solved.