trot

Trot is an Elixir web micro-framework based on Plug and Cowboy. The goal of Trot is to make common patterns in Plug easier to use, particularly when writing APIs, without sacrificing flexibility.

Routes

Routes are specified using one of the HTTP method macros: get/2, post/2, put/2, patch/2, delete/2, options/2. The first argument is a the path to route to, and the second argument is the block of code to execute. Examples are below.

If @path_root is specified, it will be prefixed to all routes in that module.

Responses

All of the following are valid return values from handlers and will be parsed into full HTTP responses:

• String of response body
• Status code, either numeric or an atom from Plug.Conn.Status
• {code, body}
• JSONable object
• {code, object}
• {:redirect, location}
• %Plug.Conn{}

Templates

Some conviences are provided for using EEx, the default templating engine include with Elixir. When the application is compiled all of templates under a given path are loaded and compiled for faster rendering. A render/2 function is generated for every template under the module attribute @template_root. By default, @template_root is “templates/“.

Example app using templates

defmodule PiedPiper do
  use Trot.Router
  use Trot.Template
  @template_root "templates/root"

  get "/compression" do
    render("compression_results.html.eex", [weissman_score: 5.2])
  end
end

Example router application

defmodule SoLoMoApp.Router do
  use Trot.Router

  # Sets status code to 200 with an empty body
  get "/" do
    200
  end

  # Returns an empty body with a status code of 404
  get "/bad" do
    :bad_request
  end

  # Sets the status code to 200 with a text body
  get "/text" do
    "Thank you for your question."
  end

  # Sets the status code to 201 with a text body
  get "/text/body" do
    {201, "Thank you for your question."}
  end

  # Sets status code to 200 with a JSON-encoded body
  get "/json" do
    %{"hyper" => "social"}
  end

  # Sets the status code to 201 with a JSON-encoded body
  get "/json/code" do
    {201, %{"hyper" => "social"}}
  end

  # Set the response manually as when using Plug directly
  get "/conn" do
    send_resp(conn, 200, "optimal tip-to-tip efficiency")
  end

  # Pattern match part of the path into a variable
  get "/presenter/:name" do
    "The presenter is #{name}"
  end

  # Redirect the incoming request
  get "/redirect" do
    {:redirect, "/text/body"}
  end
end