Cassette

Library to generate and validate CAS TGTs/STs

Installation

The package can be installed as:

1. Add cassette to your list of dependencies in mix.exs:

   def deps do

    [{:cassette, "~> 1.1"}]

   end

2. Ensure cassette is started before your application:

   def application do

    [applications: [:cassette]]

   end

Usage with the default configuration

The module Cassette includes the functions to generate TGTs and STs

This will use the default configuration (in mix.config), please refer to Cassete.Config struct for the available keys (including expiration times).

config :cassette, username: "example-user"
config :cassette, password: "topsecret"
config :cassette, base_url: "https://cas-server.example.org"
config :cassette, base_authority: "EXAMPLE"
config :cassette, service: "app.example.org"

base_authority helps on role validation and service is the default value used by Cassette.validate/2

This default configuration is returned by the Cassette.Config.default function.

Any of those values may be configured with a tuple, so configuration can be loaded using environment variables:

config :cassette, password: {:system, "SOME_ENVIRONMENT_VARIABLE"}

A round trip validation would look like this:

$ iex -S mix

iex> {:ok, tgt} = Cassette.tgt
{:ok, "TGT-11692539-ZIvKZ6TlGUBX5DBgR6egYnVvJeHyJpM2oxApxlsIYEaX2dUd9x"}

iex> {:ok, st} = Cassette.st(Cassette.Config.default.service)
{:ok, "ST-16175889-oqcTdH041YZeeLcQtYCL"}

iex> Cassette.validate(st, Cassette.Config.default.service)
{:ok, %Cassette.User{login: "sampleuser", authorities: ["ACME_ADMIN"...]}}

You are not required to call Cassette.tgt, it will be generated (or re-generated in case of expiration) when creating a ST.

Multiple configurations

If you want to use multiple cas services you can create your own module and use the Cassette.Support macro module, you can define the GenServer name and/or provide a configuration.

defmodule MyCas do
  use Cassette.Support, process_name: :MyCasServer, config: %Cassette.Config{...}
end

This other Cas service must be started as well with MyCas.start before it can be used or it may be added to your supervision tree:

defmodule YourApp do
  def start(_type, _args) do
    import Supervisor.Spec, warn: false

    children = [
      # some other apps,
      MyCas.child_spec
    ]

    opts = [strategy: :one_for_one, name: MyApp.Supervisor]
    Supervisor.started(children, opts)
  end
end

Using self signed servers

If you really really want to use insecure/self-signed certificates, use a Cassette.Config struct with insecure set to true. You can also define in your mix/config.exs like:

use Mix.Config

config :cassette, :insecure, true

Contributing

Check out Contributing guide.