Uploading image to amazon s3 using multer-s3 nodejs

Question

I am trying to upload an image to amazon s3 using multer-s3, but I am getting this error:

TypeError: Expected opts.s3 to be object node

Answer 1

I just want to add my cents,

There are many comments in all answers like how to get public URL after uploading and S3 response object and lets see implementation and cases,

// INITIALIZE NPMS
var AWS = require('aws-sdk'),
multer = require('multer'),
multerS3 = require('multer-s3'),
path = require('path');

// CONFIGURATION OF S3
AWS.config.update({
    secretAccessKey: '***********************************',
    accessKeyId: '****************',
    region: 'us-east-1'
});

// CREATE OBJECT FOR S3
const S3 = new AWS.S3();

// CREATE MULTER FUNCTION FOR UPLOAD
var upload = multer({
    // CREATE MULTER-S3 FUNCTION FOR STORAGE
    storage: multerS3({
        s3: S3,
        acl: 'public-read',
        // bucket - WE CAN PASS SUB FOLDER NAME ALSO LIKE 'bucket-name/sub-folder1'
        bucket: 'bucket-name',
        // META DATA FOR PUTTING FIELD NAME
        metadata: function (req, file, cb) {
            cb(null, { fieldName: file.fieldname });
        },
        // SET / MODIFY ORIGINAL FILE NAME
        key: function (req, file, cb) {
            cb(null, file.originalname); //set unique file name if you wise using Date.toISOString()
            // EXAMPLE 1
            // cb(null, Date.now() + '-' + file.originalname);
            // EXAMPLE 2
            // cb(null, new Date().toISOString() + '-' + file.originalname);

        }
    }),
    // SET DEFAULT FILE SIZE UPLOAD LIMIT
    limits: { fileSize: 1024 * 1024 * 50 }, // 50MB
    // FILTER OPTIONS LIKE VALIDATING FILE EXTENSION
    fileFilter: function(req, file, cb) {
        const filetypes = /jpeg|jpg|png/;
        const extname = filetypes.test(path.extname(file.originalname).toLowerCase());
        const mimetype = filetypes.test(file.mimetype);
        if (mimetype && extname) {
            return cb(null, true);
        } else {
            cb("Error: Allow images only of extensions jpeg|jpg|png !");
        }
    }
});

There are three cases, if we want to retrieve files res object from S3 after upload:

Case 1: When we are using .single(fieldname) method it will return file object in req.file

app.post('/upload', upload.single('file'), function (req, res, next) {
    console.log('Uploaded!');
    res.send(req.file);
});

Case 2: When we are using .array(fieldname[, maxCount]) method it will return file object in req.files

app.post('/upload', upload.array('file', 1), function (req, res, next) {
    console.log('Uploaded!');
    res.send(req.files);
});

Case 3: When we are using .fields(fields) method it will return file object in req.files

app.post('/upload', upload.fields([
  { name: 'avatar', maxCount: 1 },
  { name: 'gallery', maxCount: 8 }
]), function (req, res, next) {
    console.log('Uploaded!');
    res.send(req.files);
});