如何制作 node.js api 并将其部署到 heroku（postgresql 或 ZF8C0921E52FB066B4D69E8DBBE0230B4D69E8DBBE数据库）

Question

I am working on rest api with node.js and express that connects to the client side I have found a tutorial here https://www.taniarascia.com/node-express-postgresql-heroku/ and everything works fine but it will not deploy to heroku and I do not know why because everything works fine when I run it on localhost. Why is this happening?

Here is my code

index.js

const express = require("express");
const bodyParser = require("body-parser");
const cors = require("cors");
const {pool} = require("./config");
const { get } = require("mongoose");
const app = express();
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));
app.use(cors());
const getBooks = (req, res) => {
    pool.query('SELECT * FROM books', (err, results) => {
        if(err){
            throw err;
        }
        res.status(200).json(results.rows);
    });
}
const addBook = (req, res) => {
    const {author, title} = req.body;
    pool.query(
        'INSERT INTO books (author, title) VALUES ($1, $2)',
        [author, title],
        (err) => {
            if(err){
                throw err;
            }
            res.status(201).json({status: "success", message: "Book added."});
        },
    )
}

app.route("/books").get(getBooks).post(addBook);
app.listen(process.env.PORT || 8000, () => {
    console.log(`Server listening`);
})

config.js

require("dotenv").config();
const {Pool} = require("pg");
const isProduction = process.env.NODE_ENV === "production";
const connectionString = `postgresql://${process.env.DB_USER}:${process.env.DB_PASSWORD}@${process.env.DB_HOST}:${process.env.DB_PORT}/${process.env.DB_DATABASE}`;
const pool = new Pool({
    connectionString: isProduction ? process.env.DATABASE_URL : connectionString,
    ssl: isProduction,
});
module.exports = {pool};

init.sql

CREATE TABLE books (
    ID SERIAL PRIMARY KEY,
    author VARCHAR(255) NOT NULL,
    title VARCHAR(255) NOT NULL
);

INSERT INTO books (author, title)
VALUES ('J.K. Rowling', 'Harry Potter');

Answer 1

I'd have a look at this, if your app works fine locally but not on heroku it's probably a deployment issue: https://devcenter.heroku.com/articles/getting-started-with-nodejs

Specifically, l think you probably need a Procfile which is like an extra file that Heroku needs to deploy. Assuming you got set up using the cli ( https://devcenter.heroku.com/categories/command-line ) you can get more detail on how your app is failing by getting the logs using 'heroku logs -t' inside the folder you deployed from.