upload download

app.js

var express = require('express');
var bodyParser = require('body-parser');
var multer = require('multer');
var mongoose = require('mongoose');
var path = require('path');

var app = express();

var storage = multer.diskStorage({
    destination:function(req,file,cb){
         cb(null,'./public/uploads')
    },
    filename(req,file,cb){
        cb(null,file.originalname)
    }
})

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

 mongoose.connect('mongodb://localhost:27017/pics',{useNewUrlParser:false})
 .then(()=>console.log('connect')).catch(err=>console.log(err))

// making the collection(table) schema
// it contain picspath file for saving the file path
var picSchema = new mongoose.Schema({
    picspath:String
})

//collection schema will be save in db by name picsdemo 
// picModel contain the instance of picdemo by which it can manipulate data in it.
 var picModel = mongoose.model('picsdemo',picSchema)


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

app.set("views",path.resolve(__dirname,'views'));

var picPath = path.resolve(__dirname,'public');

app.use(express.static(picPath));

app.use(bodyParser.urlencoded({extended:false}))

app.get('/',(req,res)=>{
    picModel.find((err,data)=>{
             if(err){
                 console.log(err)
             }
            if(data){
                console.log(data)
                res.render('home',{data:data})
            } 
           else{
               res.render('home',{data:{}})
           } 
    })
    
})

app.post('/',upload.single('pic'),(req,res)=>{
    var x= 'uploads/'+req.file.originalname;
    var picss = new picModel({
        picspath:x
    })
    picss.save((err,data)=>{
         if(err){
             console.log(err)
         }
         else{
             console.log('data',data)
            res.redirect('/')
         }
    })
})

app.get('/download/:id',(req,res)=>{
     picModel.find({_id:req.params.id},(err,data)=>{
         if(err){
             console.log(err)
         } 
         else{
            var path= __dirname+'/public/'+data[0].picspath;
            res.download(path);
         }
     })
})

const port = process.env.PORT || 3000 ;
app.listen(port,()=>console.log(`server running at ${port}`))

module.exports = app;