s3post

README

Package s3post signs POST policy documents for browser-based file uploads to AWS S3. More details on browser-based file uploads can be found in the AWS docs.

Both s3post and policy packages use only stdlib deps, no aws sdk required.

Usage

To use this package, generate a POST policy document then pass that policy into the Sign method to receive a signature to be used in a POST form.

Details on Policy documents can be found in the AWS docs.

The policy package can be used to generate these documents if necessary.

p := s3post.New("us-east-1", secret)
encoded, signed := p.Sign(policyBytes)

See the examples folder for complete usage.

Signature details

The policy document is signed using this calculation:

Documentation

Overview

Package s3post provides a function to sign a S3 POST upload policy

Index

• type Post
  • func New(region, secret string) *Post
  • func (s *Post) Sign(policy []byte) (string, string)

Types

type Post

type Post struct {
	// contains filtered or unexported fields
}

Post holds information necessary for signing POST policy documents.

func New

func New(region, secret string) *Post

New returns an instance of Post that uses the passed in region and secret. If either is empty, environment variables will be used.

func (*Post) Sign

func (s *Post) Sign(policy []byte) (string, string)

Sign takes a POST policy and outputs the signed version of the policy as well as a signature to include in the POST form.

Signature is created by the calculation process here: http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-authentication-HTTPPOST.html

Returns the base64-encoded policy and the hex-encoded and signed policy. If an error occurs two empty strings will be returned.