igneosaur / multer-s3

multer storage engine for amazon s3

Multer S3

Streaming multer storage engine for AWS S3.

This project is mostly an integration piece for existing code samples from Multer's storage engine documentation with s3fs as the substitution piece for file system. Existing solutions I found required buffering the multipart uploads into the actual filesystem which is difficult to scale.

Installation

npm install --save multer-s3

Usage

var aws = require('aws-sdk')
var express = require('express')
var multer = require('multer')
var multerS3 = require('multer-s3')

var app = express()
var s3 = new aws.S3({ /* ... */ })

var upload = multer({
  storage: multerS3({
    s3: s3,
    bucket: 'some-bucket',
    key: function (req, file, cb) {
      cb(null, Date.now().toString())
    }
  })
})

app.post('/upload', upload.array('photos', 3), function(req, res, next) {
  res.send('Successfully uploaded ' + req.files.length + ' files!')
})

File information

Each file contains the following information exposed by multer-s3:

Key	Description	Note
size	Size of the file in bytes
bucket	The bucket used to store the file	S3Storage
key	The name of the file	S3Storage
acl	Access control for the file	S3Storage
contentType	The mimetype used to upload the file	S3Storage
location	The S3 url to access the file	S3Storage
etag	The etagof the uploaded file in S3	S3Storage

Setting ACL

ACL values can be set by passing an optional acl parameter into the multerS3 object.

var upload = multer({
  storage: multerS3({
    s3: s3,
    bucket: 'some-bucket',
    acl: 'public-read',
    key: function (req, file, cb) {
      cb(null, Date.now().toString())
    }
  })
})

Available options for canned ACL.

ACL Option	Permissions added to ACL
private	Owner gets FULL_CONTROL. No one else has access rights (default).
public-read	Owner gets FULL_CONTROL. The AllUsers group gets READ access.
public-read-write	Owner gets FULL_CONTROL. The AllUsers group gets READ and WRITE access. Granting this on a bucket is generally not recommended.
aws-exec-read	Owner gets FULL_CONTROL. Amazon EC2 gets READ access to GET an Amazon Machine Image (AMI) bundle from Amazon S3.
authenticated-read	Owner gets FULL_CONTROL. The AuthenticatedUsers group gets READ access.
bucket-owner-read	Object owner gets FULL_CONTROL. Bucket owner gets READ access. If you specify this canned ACL when creating a bucket, Amazon S3 ignores it.
bucket-owner-full-control	Both the object owner and the bucket owner get FULL_CONTROL over the object. If you specify this canned ACL when creating a bucket, Amazon S3 ignores it.
log-delivery-write	The LogDelivery group gets WRITE and READ_ACP permissions on the bucket. For more information on logs.

Testing

The tests mock all access to S3 and can be run completely offline.

npm test