aws2

aws2

A small utility to sign vanilla node.js http(s) request options using Amazon's AWS Signature Version 2.

This signature is supported by a number of (older) Amazon services, including SNS, EC2, ElastiCache, Elastic MapReduce, ImportExport and SimpleDB.

It also provides defaults for a number of core AWS headers and request parameters, making it a very easy to query AWS services, or build out a fully-featured AWS library.

NB: It is preferrable to use the newer, more secure aws4 over this library for AWS services that support AWS Signature Version 4.

Example

var http  = require('http')
  , https = require('https')
  , aws2  = require('aws2')

// given an options object you could pass to http.request
var opts = { host: 'sns.us-east-1.amazonaws.com', path: '/?Action=ListTopics' }

aws2.sign(opts) // assumes AWS credentials are available in process.env

console.log(opts)
/*
{
  host: 'sns.us-east-1.amazonaws.com',
  path: '/?Action=ListTopics&Timestamp=2013-01-12T01%3A25%3A55.553Z&SignatureVersion=2&SignatureMethod=...'
  headers: { Host: 'sns.us-east-1.amazonaws.com' }
}
*/

// we can now use this to query AWS using the standard node.js http API
http.request(opts, function(res) { res.pipe(process.stdout) }).end()
/*
<?xml version="1.0"?>
<ListTopicsResponse xmlns="http://sns.amazonaws.com/doc/2010-03-31/">
...
*/

More options

// you can pass AWS credentials in explicitly
aws2.sign(opts, { accessKeyId: '', secretAccessKey: '' })

// aws2 can infer the host from a service and region
opts = aws2.sign({ service: 'sns', region: 'us-east-1', path: '/?Action=ListTopics' })

// create a utility function to pipe to stdout (with https this time)
function request(o) { https.request(o, function(res) { res.pipe(process.stdout) }).end(o.body || '') }

// aws2 can infer the HTTP method if a body is passed in
// method will be POST and Content-Type: 'application/x-www-form-urlencoded; charset=utf-8'
request(aws2.sign({ service: 'ec2', body: 'Action=DescribeRegions&Version=2012-12-01' }))
/*
<?xml version="1.0" encoding="UTF-8"?>
<DescribeRegionsResponse xmlns="http://ec2.amazonaws.com/doc/2012-12-01/">
...
*/

// can specify any custom option or header as per usual
request(aws2.sign({
  service: 'elasticmapreduce',
  region: 'ap-southeast-2',
  method: 'POST',
  path: '/',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  body: 'Action=DescribeJobFlows&Version=2009-03-31'
}))
/*
<DescribeJobFlowsResponse xmlns="http://elasticmapreduce.amazonaws.com/doc/2009-03-31">
...
*/

// works with all other services that support Signature Version 2

request(aws2.sign({ service: 'elasticache', path: '/?Action=DescribeCacheClusters&Version=2012-11-15' }))
/*
<DescribeCacheClustersResponse xmlns="http://elasticache.amazonaws.com/doc/2012-11-15/">
...
*/

request(aws2.sign({ service: 'importexport', path: '/?Action=ListJobs&Version=2010-06-01' }))
/*
<ListJobsResponse xmlns="http://importexport.amazonaws.com/doc/2010-06-01/">
...
*/

request(aws2.sign({ service: 'sdb', path: '/?Action=ListDomains&Version=2009-04-15' }))
/*
<?xml version="1.0"?>
<ListDomainsResponse xmlns="http://sdb.amazonaws.com/doc/2009-04-15/">
...
*/

API

aws2.sign(requestOptions, [credentials])

This calculates and populates the Signature param of either requestOptions.path or requestOptions.body depending on whether it is a GET or POST request. Returns requestOptions as a convenience for chaining.

requestOptions is an object holding the same options that the node.js http.request function takes.

The following properties of requestOptions are used in the signing or populated if they don't already exist:

• hostname or host (will be determined from service and region if not given)
• method (will use 'GET' if not given or 'POST' if there is a body)
• path (will use '/' if not given)
• body (will use '' if not given)
• service (will be calculated from hostname or host if not given)
• region (will be calculated from hostname or host or use 'us-east-1' if not given)
• headers['Host'] (will use hostname or host or be calculated if not given)
• headers['Content-Type'] (will use 'application/x-www-form-urlencoded; charset=utf-8' if not given and there is a body)
• headers['Date'] (used to calculate the signature date if given, otherwise new Date is used)

Your AWS credentials (which can be found in your AWS console) can be specified in one of two ways:

• As the second argument, like this:

aws2.sign(requestOptions, {
  secretAccessKey: "<your-secret-access-key>",
  accessKeyId: "<your-access-key-id>"
})

• From process.env, such as this:

export AWS_SECRET_ACCESS_KEY="<your-secret-access-key>"
export AWS_ACCESS_KEY_ID="<your-access-key-id>"

(will also use AWS_ACCESS_KEY and AWS_SECRET_KEY if available)

Installation

With npm do:

npm install aws2