upload the file from nodejs

 

 

 

upload the file from nodejs

This blog we have seen mongodb basic and how is it work with installation and after installation, we have already seen mongodb basic, CRUD operation, connect mongodb with nodejs, read, update, delete, POST, GET API etc. we should not face any problem while making Database, collection(table) and using the data in nodejs even whenever we will make API. Read data from mongodb in nodejs

• # What is Mongoose
• # Install Mongoose
  
• # Install Multer npm package
  
• # Make Router for upload file
  

 

Now in this blog  we will use mongoose. There is an npm package to connect nodes to mongodb. Mongoose is a MongoDB object modeling tool designed to work in an asynchronous environment. They created mongoose by improving mongodb, with the help of which you can create schemas and models of mongoose's movements.

Suppose that there are 4 fields in our database (like name, brand, price, category) and the user wants to add a 5th field also (like color) but we want to add only 4 fields, for this we create schemas.

Here you can also define TYPE in schemas like price type is numeric but if any user wants to use quotes (" " ' ') then we can stop the user for this.

in sort we can apply validation in mongoose but we can't in directly mongodb.

 

 

 What is MongoDB

 

MongoDB is a popular open-source NoSQL (non-relational) database management system. NoSQL means no structure like it is look like an object while in SQL it is a structure query language like SELECT CustomerName, City FROM Customers; (The SELECT statement is used to select data from a database.) But NoSQL database is useless...NOT completely because of whenever we want add extra column in database then it is possible through NoSQL MongoDB.   

 

MongoDB installation - CLICK HERE

MongoDB Basic Command - CLICK HERE

About MongoDB vs SQL - CLICK HERE

CRUD in MongoDB - CLICK HERE

 

 

Object Like - 

 

 

{
  "_id": {
    "$oid": "659ad46e0382148123c82841"
  },
  "name": "moto G60",
  "brand": "motorola",
  "price": 16500,
  "category": "mobile"
}

 

 

MongoDB is a type of database that helps store and manage large amounts of data in a flexible and scalable way. Unlike SQL, MongoDB doesn't require a fixed structure for the data, allowing you to store information in a more versatile format.

• MongoDB is a NoSQL database.
• The data stored in a collection
• Collection don't have row and columns
• Data is stored in the form of object.

Install Mongoose

For this you need to copy this (npm i mongoose) and paste it in project's terminal.

https://www.npmjs.com/package/mongoose

 

 

 

 

 

Install Multer npm package

 

First we need to install multer npm package in our project, if you want you can also write the code without this npm package. Let's first install it.

Simple go this link - CLICK HERE

CMD for installation - npm i multer

 

 

Make Router for upload file 

 

Now we will write code of upload file with the npm package multer but first we will send data POST method and using /upload endpoint and also you can create a folder named as uploads.

 

 

const express = require('express')
const multer = require('multer');
const app = express();


app.post("/upload" , (req, resp) => {
    resp.send("File uploaded")
});


app.listen(8000)

 

 

 

 

 

const upload = multer({
    storage: multer.diskStorage({
        destination:function(req, file, cb)
        {
            cb(null,'uploads/') //folder to save the files in 

        },
        filename:function(req, file, cb)
        {
           // cb(null, file.fieldname + "-" + Date.now() + ".jpg" )
            //if you can extract extension from  file then use this code
            var  ext=file.originalname.split(".");
            if(ext[ext.length-1]==='jpg' || ext[ext.length -1 ] === 'png'){
                cb(null , file.fieldname+ '-' +Date.now()+"."+ext[ext.length -1]);
            }else{
                cb(new Error('Error : Only jpg and png are allowed'));
        }
    }
    })
}).single("user_file");// field name in form data

 

 

 

 Let's breakdown the code.

1) Multer Configuration:

const upload = multer({
    storage: multer.diskStorage({
        // ... configuration options ...
    })
}).single("user_file");

# upload: This variable holds the configured multer middleware. It's set up to handle a single file upload.
# multer: This is the Multer middleware.
# storage: Multer's storage option defines how files should be stored. In this case, it uses multer.diskStorage to specify that files should be stored on the disk.


multer.diskStorage({
    destination: function(req, file, cb) {
        cb(null, 'uploads/');
    },
    filename: function(req, file, cb) {
        // ... filename configuration ...
    }
})




destination: A function that determines the destination folder for storing uploaded files. In this example, it's set to 'uploads/'. You need to make sure the 'uploads' directory exists in your project.

filename: A function that determines the name of the uploaded file. It checks the file extension and appends a timestamp to the original filename if it's a jpg or png file. If the file extension is not allowed, it throws an error.




3) Error Handling:


if (ext[ext.length - 1] === 'jpg' || ext[ext.length - 1] === 'png') {
    cb(null, file.fieldname + '-' + Date.now() + '.' + ext[ext.length - 1]);
} else {
    cb(new Error('Error: Only jpg and png are allowed'));
}




This part of the code checks the file extension. If the extension is 'jpg' or 'png', it generates a filename with the original fieldname, a timestamp, and the file extension. If the extension is not allowed, it invokes the callback with an error.


}).single("user_file");




The .single("user_file") part specifies that it's expecting a single file upload with the field name "user_file". The field name should match the one used in your HTML form's file input.

 

 Whole Code

const express = require('express')
const multer = require('multer');
const app = express();


const upload = multer({
    storage: multer.diskStorage({
        destination:function(req, file, cb)
        {
            cb(null,'uploads/') //folder to save the files in 

        },
        filename:function(req, file, cb)
        {
          
            var  ext=file.originalname.split(".");
            if(ext[ext.length-1]==='jpg' || ext[ext.length -1 ] === 'png'){
                cb(null , file.fieldname+ '-' +Date.now()+"."+ext[ext.length -1]);
            }else{
                cb(new Error('Error : Only jpg and png are allowed'));
        }
    }
    })
}).single("user_file");// field name in form data

app.post("/upload", upload , (req, resp) => {
    resp.send("File uploaded")
});


app.listen(8000)

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