index.js

var S3FS = require('s3fs');
var crypto = require('crypto');
var gm = require('gm');
var mime = require('mime');

const DEFAULT_FORMAT = 'jpg';

function S3Storage(opts) {
  if (!opts.bucket) {
    throw new Error('bucket is required');
  }
  if (!opts.secretAccessKey) {
    throw new Error('secretAccessKey is required');
  }
  if (!opts.accessKeyId) {
    throw new Error('accessKeyId is required');
  }
  if (!opts.region) {
    throw new Error('region is required');
  }
  if (!opts.dirname) {
    throw new Error('dirname is required');
  }
  this.options = opts;
  this.options.filename = (opts.filename || getFilename)
  this.s3fs = new S3FS(opts.bucket, opts);
  if(!this.options.gm) {
    this.options.gm = {};
  }
  if(!this.options.s3) {
    this.options.s3 = {};
  }
}

function getFilename(req, file, cb) {
  crypto.pseudoRandomBytes(16, function(err, raw) {
    cb(err, err ? undefined : raw.toString('hex'));
  });
}

S3Storage.prototype._handleFile = function(req, file, cb) {
  var self = this;
  self.options.filename(req, file, function(err, filename) {
    if (err) {
      return cb(err);
    }
    var filePath = self.options.dirname + '/' + filename;
    var contentType;
    if(self.options.gm.format) {
      contentType = mime.lookup(self.options.gm.format);
    } else {
      contentType = mime.lookup(DEFAULT_FORMAT);
    }
    var s3options = self.options.s3;
    s3options.ContentType = contentType;
    var outStream = self.s3fs.createWriteStream(filePath, s3options);
    gm(file.stream)
      .autoOrient()
      .resize(self.options.gm.width)
      .noProfile()
      .stream(self.options.gm.format || DEFAULT_FORMAT)
      .pipe(outStream);
    outStream.on('error', cb);
    outStream.on('finish', function() {
      cb(null, {
        size: outStream.bytesWritten,
        key: filePath,
        location: 'https://' + self.options.bucket + '.s3.amazonaws.com/' + filePath
      });
    });
  });
};

S3Storage.prototype._removeFile = function(req, file, cb) {
  this.s3fs.unlink(file.key, cb);
};

module.exports = function(opts) {
  return new S3Storage(opts);
};