Sigaws

An Elixir library to sign and verify HTTP requests using AWS Signature V4.

Installation

This package can be installed by adding sigaws to your list of dependencies in mix.exs:

def deps do
  [{:sigaws, "~> 0.1.0"}]
end

Documentation

• Blog
• Module Doc
• Plug built using this

Examples

Signature to be passed as request headers

url = "http://api.endpoint.host:5000/somthing?a=10&b=20"
headers = %{"header1" => "value1", "header2" => "value2"}
{:ok, %{} = sig_data, _} =
  Sigaws.sign_req(url,
                  headers: headers,
                  region: "delta-quad",
                  service: "my-service",
                  access_key: "some-access-key",
                  secret: "some-secret")

{:ok, resp} = HTTPoison.get(url, Map.merge(headers, sig_data))

Signature to be passed in query string ("presigned" URL)

url = "http://api.endpoint.host:5000/somthing?a=10&b=20"
{:ok, %{} = sig_data, _} =
  Sigaws.sign_url(url,
                  body: :unsigned,
                  expires_in: 5 * 60,                 # 5 minutes
                  region: "delta-quad",
                  service: "my-service",
                  access_key: "some-access-key",
                  secret: "some-secret")

presigned_url = Sigaws.Util.add_params_to_url(url, sig_data)

Signature Verification

The verification process relies on a provider module that implements Sigaws.Provider behavior. The provider is expected to supply the signing key based on the information present in the context (primarily the access key).

{:ok, %Sigaws.Ctxt{} = ctxt} =
  Sigaws.Verify(conn.request_path,
    method: conn.method,
    params: conn.query_params,
    headers: conn.req_headers,
    body: get_raw_body(conn),
    provider: SigawsQuickStartProvider)

The above example is using the sigaws_quickstart_provider Hex package. Check the blog listed earlier.

Test Suite

Part of the tests in this package rely on AWS Signature Version 4 Test Suite. This test suite should be downloaded and unpacked before running the tests.

mkdir -p test/testsuite
cd test/testsuite
wget https://docs.aws.amazon.com/general/latest/gr/samples/aws-sig-v4-test-suite.zip
unzip aws-sig-v4-test-suite.zip