Controllers

All controller actions should have an arity of 2, with the first argument being a Plug.Conn representing the current connection and the second argument being a Keyword list of any parameters captured in the route path; both of these arguments are passed to the controller action from the router when a request is received.

To illustrate: if your router receives a GET request for /2, and your router has a route that points a GET for /:id to YourApplication.Controller.Main.show, your controller's show will receive a Plug.Conn as its first argument and [id: 2] as its second argument. Similarly, if your router receives a POST request for /2?title=foo&body=Hello%20world, and has a route that points a POST for /:id to YourApplication.Controller.Main.update, your controller's update will receive a Plug.Conn as its first argument (where conn.params is %{"title" => "foo", "body" => "Hello world"}) and [id: 2] as its second argument.

Sugar bundles these response helpers to assist in sending a response:

  • render/2 - conn, template - sends a normal response.
  • halt!/1 - conn - ends the response.
  • not_found/1 - conn - sends a 404 (Not found) response.
  • json/2 - conn, data - sends a normal response with data encoded as JSON.
  • raw/1 - conn - sends response as-is. It is expected that status codes, headers, body, etc have been set by the controller action.

Example

defmodule Hello do
  use Sugar.Controller

  def index(conn, []) do
    render conn, "showing index controller"
  end

  def show(conn, args) do
    render conn, "showing page \#{args[:id]}"
  end

  def update(conn, args) do
    %{"title" => title, "body" => body} = conn.params
    render conn, "edited page #{args[:id]} with title: #{title}, body: #{body}"
  end

  def create(conn, []) do
    render conn, "page created"
  end

  def get_json(conn, []) do
    json conn, %{message: "foobar"}
  end
end

Sugar is released under the MIT License.

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