我如何使用 nodejs 在 mysql 数据库中保存 json 文件

Question

I'm trying to import a JSON file and store it in the MySQL database but resources are not much clear and I don't know how I can fix what I need trying with this code which is a store CSV file and trying to convert it into JSON file: any help or idea or resourses to know how I can fix it or make it much better?

const fs = require("fs");
const express = require('express')
const app = express()
const bodyparser = require('body-parser')
const csv = require('fast-csv');
const mysql = require('mysql')
const multer = require('multer')
const path = require('path')

fs.readFile("todo.json", (err, data) => {
  let todotxt = convertJSON2TXT(data); 
  saveTXT(todotxt); 
});

function convertJSON2TXT(data) {
  let todotxt = "";
  let todo = JSON.parse(data.toString());
  todo.forEach((val) => {
    val.isArchived = val.isArchived ? 1 : 0;
    val.startDate = val.startDate.replace("T", " ").substr(0, 19);
  });
  todo.forEach((val) => {
    todotxt += `${val.id}\t${val.todo}\t${val.isArchived}\t${val.startDate}\r\n`;
  });

  return todotxt.substr(0, todotxt.length - 2);
}

function saveTXT(todotxt) {
  fs.writeFile("todo.txt", todotxt, (err) => {
    if (err) {
      console.log("error occurs");
    } else {
      console.log("write to todo.txt:");
      console.log(todotxt);
    }
  });
}


//use express static folder
app.use(express.static("./public"))

// body-parser middleware use
app.use(bodyparser.json())
app.use(bodyparser.urlencoded({
    extended: true
}))

// Database connection
const db = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "",
    database: "test"
})

db.connect(function (err) {
    if (err) {
        return console.error('error: ' + err.message);
    }
    console.log('Connected to the MySQL server.');
})

//! Use of Multer
var storage = multer.diskStorage({
    destination: (req, file, callBack) => {
        callBack(null, './uploads/')    
    },
    filename: (req, file, callBack) => {
        callBack(null, file.fieldname + '-' + Date.now() + path.extname(file.originalname))
    }
})

var upload = multer({
    storage: storage
});

//! Routes start

//route for Home page
app.get('/', (req, res) => {
  res.sendFile(__dirname + '/index.html');
});

//@type   POST
// upload csv to database
app.post('/uploadfile', upload.single("uploadfile"), (req, res) =>{
    convertJSON2TXT(__dirname + '/uploads/' + req.file.filename);
    console.log('CSV file data has been uploaded in mysql database ' + err);
});

function UploadCsvDataToMySQL(filePath){
    let stream = fs.createReadStream(filePath);
    let csvData = [];
    let csvStream = csv
        .parse()
        .on("data", function (data) {
            csvData.push(data);
        })
        .on("end", function () {
            // Remove Header ROW
            csvData.shift();
 
            // Open the MySQL connection
            db.connect((error) => {
                if (error) {
                    console.error(error);
                } else {
                    let query = 'INSERT INTO todo (id, todo, isArchived, startDate) VALUES ?';
                    db.query(query, [csvData], (error, response) => {
                        console.log(error || response);
                    });
                }
            });
            
            // delete file after saving to MySQL database
            // -> you can comment the statement to see the uploaded CSV file.
            fs.unlinkSync(filePath)
        });
 
    stream.pipe(csvStream);
}

//create connection
const PORT = process.env.PORT || 3000
app.listen(PORT, () => console.log(`Server is running at port ${PORT}`))

Answer 1

Doesn't data.toString() give you the JSON as a string ? If so, there should be no need to "parse" it into an "object", then try to convert back to a "string".