Streaming file from S3 with Express including information on length and filetype

Question

Using the aws-sdk module and Express 4.13, it\'s possible to proxy a file from S3 a number of ways.

This callback version will return the file body as a

Answer 1

Building on André Werlang's answer, we have done the following to augment AWS Request objects with a forwardToExpress method:

const _ = require('lodash');
const AWS = require('aws-sdk');

AWS.Request.prototype.forwardToExpress = function forwardToExpress(res, next) {
    this
    .on('httpHeaders', function (code, headers) {
        if (code < 300) {
            res.set(_.pick(headers, 'content-type', 'content-length', 'last-modified'));
        }                            
    })
    .createReadStream()
    .on('error', next)
    .pipe(res);
};    

Then, in our route handlers, we can do something like this:

s3.getObject({Bucket: myBucket, Key: myFile}).forwardToExpress(res, next);