knox

knox

Node Amazon S3 Client.

Features

• Familiar API (client.get(), client.put(), etc)
• Very Node-like low-level request capabilities via http.Client
• Higher-level API with client.putStream(), client.getFile(), etc.
• Copying and multi-file delete support
• Streaming file upload and direct stream-piping support

Examples

The following examples demonstrate some capabilities of knox and the S3 REST API. First things first, create an S3 client:

var client = knox.createClient({
    key: '<api-key-here>'
  , secret: '<secret-here>'
  , bucket: 'learnboost'
});

By default knox will send all requests to the global endpoint (bucket.s3.amazonaws.com). This works regardless of the region where the bucket is. But if you want to manually set the endpoint (for performance reasons) you can do it with the endpoint option.

PUT

If you want to directly upload some strings to S3, you can use the Client#put method with a string or buffer, just like you would for any http.Client request. You pass in the filename as the first parameter, some headers for the second, and then listen for a 'response' event on the request. Then send the request using req.end(). If we get a 200 response, great!

var object = { foo: "bar" };
var string = JSON.stringify(object);
var req = client.put('/test/obj.json', {
    'Content-Length': string.length
  , 'Content-Type': 'application/json'
});
req.on('response', function(res){
  if (200 == res.statusCode) {
    console.log('saved to %s', req.url);
  }
});
req.end(string);

By default the x-amz-acl header is public-read, meaning anyone can GET the file. To alter this simply pass this header to the client request method.

client.put('/test/obj.json', { 'x-amz-acl': 'private' });

Each HTTP verb has an alternate method with the "File" suffix, for example put() also has a higher level method named putFile(), accepting a source filename and performing the dirty work shown above for you. Here is an example usage:

client.putFile('my.json', '/user.json', function(err, res){
  // Logic
});

Another alternative is to stream via Client#putStream(), for example:

http.get('http://google.com/doodle.png', function(res){
  var headers = {
      'Content-Length': res.headers['content-length']
    , 'Content-Type': res.headers['content-type']
  };
  client.putStream(res, '/doodle.png', headers, function(err, res){
    // Logic
  });
});

And if you want a nice interface for putting a buffer or a string of data, use Client#putBuffer():

var buffer = new Buffer('a string of data');
var headers = {
  'Content-Type': 'text/plain'
};
client.putBuffer(buffer, '/string.txt', headers, function(err, res){
  // Logic
});

Note that both putFile and putStream will stream to S3 instead of reading into memory, which is great. And they return objects that emit 'progress' events too, so you can monitor how the streaming goes! The progress events have fields written, total, and percent.

GET

Below is an example GET request on the file we just shoved at S3. It simply outputs the response status code, headers, and body.

client.get('/test/Readme.md').on('response', function(res){
  console.log(res.statusCode);
  console.log(res.headers);
  res.setEncoding('utf8');
  res.on('data', function(chunk){
    console.log(chunk);
  });
}).end();

There is also Client#getFile() which uses a callback pattern instead of giving you the raw request:

client.getFile('/test/Readme.md', function(err, res){
  // Logic
});

DELETE

Delete our file:

client.del('/test/Readme.md').on('response', function(res){
  console.log(res.statusCode);
  console.log(res.headers);
}).end();

Likewise we also have Client#deleteFile() as a more concise (yet less flexible) solution:

client.deleteFile('/test/Readme.md', function(err, res){
  // Logic
});

HEAD

As you might expect we have Client#head and Client#headFile, following the same pattern as above.

Advanced Operations

Knox supports a few advanced operations. Like copying files:

client.copy('/test/Readme.md', '/test/Readme.markdown').on('response', function(res){
  console.log(res.statusCode);
  console.log(res.headers);
}).end();

// or

client.copyFile('/test/Readme.md', '/test/Readme.markdown', function(err, res){
  // Logic
});

and deleting multiple files at once:

client.deleteMultiple(['/test/Readme.md', '/test/Readme.markdown'], function(err, res){
  // Logic
});

And you can always issue ad-hoc requests, e.g. the following to get an object's ACL:

client.request('GET', '/test/Readme.md?acl').on('response', function(res){
  // Read and parse the XML response.
  // Everyone loves XML parsing.
}).end();

Running Tests

To run the test suite you must first have an S3 account, and create a file named ./auth, which contains your credentials as json, for example:

{
  "key":"<api-key-here>",
  "secret":"<secret-here>",
  "bucket":"<your-bucket-name>"
}

Then install the dev dependencies and execute the test suite:

$ npm install
$ npm test