AWS CloudFront URL Signature Utility

NOTE

The AWS SDK for JavaScript has added support for generating signed URLs and Cookies. Please see Class: AWS.CloudFront.Signer

Generating signed URLs for CloudFront links is a little more tricky than for S3. It's because signature generation for S3 URLs is handled a bit differently than CloudFront URLs and this functionality is not currently supported by the aws-sdk library for JavaScript. In case you also need to do this, I've created this simple utility to make things easier.

Usage

Requirements

• Node.js >=18
• Active CloudFront distribution with origin configured

Configuring CloudFront

1. Create a CloudFront distribution

2. Configure your origin with the following settings:

   Origin Domain Name: {your-s3-bucket} Restrict Bucket Access: Yes Grant Read Permissions on Bucket: Yes, Update Bucket Policy

3. Create CloudFront Key Pair. more info

Installing

npm install aws-cloudfront-sign

TypeScript

import { SignatureOptions } from 'aws-cloudfront-sign/types'

Upgrading from 2.x to 3.x

• There shouldn't be any breaking changes when coming to 3.x. RTMP URLs were deprecated by Amazon but that will affect all versions.
• Support for ES Modules was added
• Support for TypeScript was added

Upgrading from 1.x to 2.x

• expireTime now takes it's value as milliseconds, Date, or moment instead of seconds.

API

getSignedUrl(url, options)

• @param {String} url - Cloudfront URL to sign
• @param {Object} options - URL signature options
• @return {String} signedUrl - Signed CloudFrontUrl

getSignedCookies(url, options)

• @param {String} url - Cloudfront URL to sign
• @param {Object} options - URL signature options
• @return {Object} cookies - Signed AWS cookies

getSignedRTMPUrl(domainName, s3key, options)

⛔️ Deprecated: RTMP Support Discontinuing on December 31, 2020

• @param {String} domainName - Domain name of your Cloudfront distribution
• @param {String} s3key - Path to s3 object
• @param {Object} options - URL signature options
• @return {Object} url.rtmpServerPath - RTMP formatted server path
• @return {Object} url.rtmpStreamName - Signed RTMP formatted stream name

Options

• expireTime (Optional - Default: 1800 sec == 30 min) - The time when the URL should expire. Accepted values are
  • number - Time in milliseconds (new Date().getTime() + 1800000)
  • moment - Valid momentjs object (moment().add(1, 'day'))
  • Date - Javascript Date object (new Date(2016, 0, 1))
• ipRange (Optional) - IP address range allowed to make GET requests for your signed URL. This value must be given in standard IPv4 CIDR format (for example, 10.52.176.0/24).
• keypairId - The access key ID from your Cloudfront keypair

• privateKeyString || privateKeyPath - The private key from your Cloudfront keypair. It can be provided as either a string or a path to the .pem file. Note: When providing the private key as a string, ensure that the newline character is also included.

  const privateKeyString =
  '-----BEGIN RSA PRIVATE KEY-----\n'
  'MIIJKAIBAAKCAgEAwGPMqEvxPYQIffDimM9t3A7Z4aBFAUvLiITzmHRc4UPwryJp\n'
  'EVi3C0sQQKBHlq2IOwrmqNiAk31/uh4FnrRR1mtQm4x4IID58cFAhKkKI/09+j1h\n'
  'tuf/gLRcOgAXH9o3J5zWjs/y8eWTKtdWv6hWRxuuVwugciNckxwZVV0KewO02wJz\n'
  'jBfDw9B5ghxKP95t7/B2AgRUMj+r47zErFwo3OKW0egDUpV+eoNSBylXPXXYKvsL\n'
  'AlznRi9xNafFGy9tmh70pwlGG5mVHswD/96eUSuLOZ2srcNvd1UVmjtHL7P9/z4B\n'
  'KdODlpb5Vx+54+Fa19vpgXEtHgfAgGW9DjlZMtl4wYTqyGAoa+SLuehjAQsxT8M1\n'
  'BXqfMJwE7D9XHjxkqCvd93UGgP+Yxe6H+HczJeA05dFLzC87qdM45R5c74k=\n'
  '-----END RSA PRIVATE KEY-----'

  Also, here are some examples if prefer to store your private key as a string but within an environment variable.

  # Local env example
  CF_PRIVATE_KEY="$(cat your-private-key.pem)"
  
  # Heroku env
  heroku config:set CF_PRIVATE_KEY="$(cat your-private-key.pem)"

Examples

Creating a signed URL

By default the URL will expire after half an hour.

// ESM: import { getSignedUrl } from 'aws-cloudfront-sign'
const cf = require('aws-cloudfront-sign')
const options = {keypairId: 'APKAJM2FEVTI7BNPCY4A', privateKeyPath: '/foo/bar'}
const signedUrl = cf.getSignedUrl('http://xxxxxxx.cloudfront.net/path/to/s3/object', options);
console.log('Signed URL: ' + signedUrl);

Creating signed cookies

// ESM: import { getSignedCookies } from 'aws-cloudfront-sign'
const cf = require('aws-cloudfront-sign')
const options = {keypairId: 'APKAJM2FEVTI7BNPCY4A', privateKeyPath: '/foo/bar'}
const signedCookies = cf.getSignedCookies('http://xxxxxxx.cloudfront.net/*', options);

// You can now set cookies in your response header. For example:
for(var cookieId in signedCookies) {
 res.cookie(cookieId, signedCookies[cookieId]);
}