@livescale/s3-streams

s3-streams

Support for streaming reads and writes from and to S3 using Amazon's native API.

Amazon makes it a giant pain to do anything stream-like when it comes to S3 (given the general restriction that every request needs a Content-Length header). We provide native stream classes (both Readable and Writable) that wrap aws-sdk S3 requests and responses to make your life easier.

IMPORTANT: This library uses the streams3 API. In order to provide compatibility with older versions of node we make use of readable-stream. This is unlikely to have any effect on your code but has not yet been well tested.

If you are using node 0.8 you must ensure your version of npm is at least 1.4.6.

Features:

• Native read streams,
• Native write streams,
• Smart piping.

Usage

npm install s3-streams

Write Streams

Create streams for uploading to S3:

var S3 = require('aws-sdk').S3,
	S3S = require('s3-streams');

var upload = S3S.WriteStream(new S3(), {
	Bucket: 'my-bucket',
	Key: 'my-key',
	// Any other AWS SDK options
	// ContentType: 'application/json'
	// Expires: new Date('2099-01-01')
	// ...
});

Read Streams

Create streams for downloading from S3:

var S3 = require('aws-sdk').S3,
	S3S = require('s3-streams');

var download = S3S.ReadStream(new S3(), {
	Bucket: 'my-bucket',
	Key: 'my-key',
	// Any other AWS SDK options
});

Smart Piping

Smart pipe files over HTTP:

var http = require('http'),
    S3 = require('aws-sdk').S3,
	S3S = require('s3-streams');

http.createServer(function(req, res) {
    var src = S3S.ReadStream(...);
    // Automatically sets the correct HTTP headers
    src.pipe(res);
})

Smart pipe files on S3:

var S3 = require('aws-sdk').S3,
	S3S = require('s3-streams');

var src = S3S.ReadStream(...),
	dst = S3S.WriteStream(...);

// No data ever gets downloaded locally.
src.pipe(dst);

Extras

You can create streams with different settings by creating a partial for the specific S3 instance you have:

var instance = new S3(), s3 = {
	createReadStream: _.partial(S3ReadStream, instance),
	createWriteStream: _.partial(S3WriteStream, instance)
}

var stream = s3.createReadStream({ Bucket: 'my-bucket', Key: 'my-key' });

Existing frameworks:

• knox (doesn't use native AWS SDK, no true streaming support)
• s3-upload-stream (doesn't use node streams API, no support for streaming downloads)
• s3-download-stream (only does downloads, downloads are streamed by S3 part, not by individual buffer chunks)
• streaming-s3 (overall terrible API; no actual streams)
• create-s3-object-write-stream (probably one of the better ones)