# Checkpoint
**Checkpoint is a minimal authorization library based off of Ruby's [pundit](https://github.com/varvet/pundit) library**
## Usage
Add the following to `lib/example_web` or to the beginning of your controller
```elixir
defmodule ExampleWeb.PageController do
use ExampleWeb, :controller
plug(Checkpoint)
def index(conn, _params) do
render conn, "index.html"
end
end
def controller do
quote do
use Phoenix.Controller, namespace: CheckpointWeb
import Plug.Conn
import ExampleWeb.Router.Helpers
import ExampleWeb.Gettext
plug(Checkpoint)
end
end
```
**Note: This library will not work if you add the plug to your router's pipeline as it depends on knowing the controller module**
This plug expects a corresponding policy module that has the same naming structure as the controller. It will dynamically call a method in the policy that corresponds to the action called in the controller with a `?` appended. An example is provided below for clarity. e.g. ExampleWeb.PageController#index => ExampleWeb.PagePolicy#index?
```elixir
defmodule ExampleWeb.PagePolicy do
# receives conn, assigns, and params
def index?(conn, %{current_user: user}, _params) do
if user.admin do
{:ok, conn}
else
{:error, %{
path: "/login",
message: "You must be an admin in order to access this page"
}}
end
end
end
```
You can return either an {:ok, conn} tuple to signify that the request is authorized or an {:error, map} tuple to signify that authorization has failed.
## Installation
If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `checkpoint` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:checkpoint, "~> 0.1.0"}
]
end
```
Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
be found at [https://hexdocs.pm/checkpoint](https://hexdocs.pm/checkpoint).