Add files via upload

main

Author: rajghosh2000

app.js

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+const express = require('express');
+const bodyParser = require('body-parser');
+const path = require('path');
+const crypto = require('crypto');
+const mongoose = require('mongoose');
+const multer = require ('multer');
+const GridfsStorage = require ('multer-gridfs-storage');
+const Grid = require ('gridfs-stream');
+const methodeOverride = require ('method-override');
+
+const app = express();
+
+//MIDDLE WARE FUNCTIONS
+app.use(bodyParser.json());     //https://stackoverflow.com/questions/38306569/what-does-body-parser-do-with-express
+app.use(methodeOverride('_method'));    //https://stackoverflow.com/questions/23643694/whats-the-role-of-the-method-override-middleware-in-express-4
+app.set('view engine','ejs');
+
+//MONGODB Uniform Resource Identifier
+const mongoURI = "mongodb://localhost:27017/folder";
+
+//Creating Mongo Connection
+const conn = mongoose.createConnection(mongoURI);
+
+// declaring gfs globally
+let gfs;
+//Using gridfs along with mongo
+conn.once('open', () => { 
+    // init stream
+    gfs = Grid(conn.db, mongoose.mongo);
+    gfs.collection('uploads');
+  })
+
+
+// Create storage engine
+const storage = new GridfsStorage({
+  url: 'mongodb://localhost:27017/folder',
+    file: (req, file) => {
+      return new Promise((resolve, reject) => {
+        crypto.randomBytes(16, (err, buf) => {  // check module_used.js for details
+          if (err) {
+            return reject(err);
+          }
+          const filename = buf.toString('hex') + path.extname(file.originalname);
+          const fileInfo = {
+            filename: filename,
+            bucketName: 'uploads'//name of bucket list and collection must be same
+          };
+          resolve(fileInfo);
+        });
+      });
+    }
+  });
+  const upload = multer({ storage });
+  
+// GET / ---> LOAD FORM TO DISPLAY ALL THE FILES PRESENT
+
+app.get('/',(req,res)=>{
+    gfs.files.find().toArray((err,files)=>{
+        if(!files || files.length==0){
+            res.render('index',{files:false});
+        }
+        else{
+            files.map(file=>{  //map is a strong function mainly to desmostrate for image objects to other files
+                if(file.contentType === 'image/jpeg' || file.contentType === 'image/png' )  
+                    {
+                        file.isImage = true;
+                    }
+                else
+                   {
+                        file.isImage = false;
+                   } 
+                
+            });
+            res.render('index',{files:files});
+        }
+        
+    });
+});
+
+
+// route GET / i.e. loads form
+app.get('/',(req,res)=>{
+    var retVal = prompt("FILE UPLOADED!!");
+    res.render('index');
+});
+
+// route POST/upload  i.e. Uploads file to db 
+app.post('/upload', upload.single('file'), (req,res)=>{ // upload is middle ware used along with single as we are uploading only one file at a time and also in the bracket we have written the name of the file name of the command used in index.ejs page line no.17
+    //res.json({file:req.file}); --> this wsa to to just check the uploaded file's json text
+    res.redirect('/'); // redirects immediately to the home page after the upload is over
+
+});
+
+// GET/files --> DISPLAY ALL THE FILES PRESENT IN THE JSON
+app.get('/files',(req,res)=>{
+    gfs.files.find().toArray((err,files) =>{
+            // Check if files exists
+            if(!files || files.length===0){
+                return res.status(404).json({
+                    err: 'No files Found'
+                });
+            }
+            //File Exists
+            return res.json(files);
+    });
+});
+
+//GET/files/:filename --->SingleFile --> Display a single file in the JSon format
+app.get('/files/:filename',(req,res)=>{
+    gfs.files.findOne({ filename: req.params.filename},(err,file) =>{
+            // Check if files exists
+            if(!file || file.length===0){
+                return res.status(404).json({
+                    err: 'No files Found'
+                });
+            }
+            //File Exists
+            return res.json(file);
+    });
+});
+//GET/image/:filename --->SingleFile --> Display a IMAGE AFTER CHECKING FORMAT
+app.get('/image/:filename',(req,res)=>{
+    gfs.files.findOne({ filename: req.params.filename},(err,file) =>{
+            // Check if files exists
+            if(!file || file.length===0){
+                return res.status(404).json({
+                    err: 'No files Found'
+                });
+            }
+            //File Exists
+               // CHECK IF ITS AN IMAGE
+               if(file.contentType === 'image/jpeg' || file.contentType === 'image/png' ){
+                   // READ o/p to browser
+                   const readstream = gfs.createReadStream(file);
+                   readstream.pipe(res);
+               }
+               else{
+                   res.status(404).json({
+                       err : 'NOT AN IMAGE'
+                   });
+               }
+    });
+});
+
+
+
+const PORT = process.env.PORT || 5000;
+
+app.listen(PORT, ()=>console.log(`SERVER RUNNING AT PORT ${PORT}`));

modules_used.js

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+//ejs -- https://www.npmjs.com/package/ejs
+//body-parser -- https://www.npmjs.com/package/body-parser
+//gridfs-stream -- https://www.npmjs.com/package/gridfs-stream
+//mongoose -- https://www.npmjs.com/package/mongoose
+//multer -- https://www.npmjs.com/package/multer
+//multer-gridfs-storage -- https://www.npmjs.com/package/multer-gridfs-storage
+//method-override -- https://www.npmjs.com/package/method-override
+
+
+//helper txt -- https://github.com/aheckmann/gridfs-stream
+//helper txt -- https://github.com/devconcept/multer-gridfs-storage