kevinlang/newton

Alchemical web development formulated with a DSL

Newton

Newton is a DSL for quickly creating Elixir web applications with minimal effort:

# lib/my_app.ex
defmodule MyApp do
  use Newton
  
  get "/" do
    text(conn, "Hello world!")
  end
end

Install the Hex package by adding it to your deps, and specify your application mod:

# mix.exs
defmodule MyApp.MixProject do
  #...

  def application do
    [
      extra_applications: [:logger],
      mod: {MyApp, []}
    ]
  end

  defp deps do
    [{:newton, "~> 0.1.0"}]
  end
end

Fetch your new dependency:

mix deps.get

And run with:

mix run --no-halt

View at: http://localhost:1642

The code you changed will not take effect until you restart the server. Please restart the server every time you change or use newton_reload.

Supervision

In addition to being started as an application directly, your Newton server can also be started under your application's supervision tree.

Simply update your MyApp.Application to include the relevant module:

children = [
  {MyApp, []}
]

Routes

In Newton, a route is an HTTP method paired with a URL-matching pattern. Each route is associated with a block:

get "/" do
  .. show something ..
end

post "/" do
  .. create something ..
end

put "/" do
  .. replace something ..
end

patch "/" do
  .. modify something ..
end

delete "/" do
  .. annihilate something ..
end

options "/" do
  .. appease something ..
end

Each route receives a conn variable containing a Plug.Conn struct.

Route patterns may include named parameters which will be available in the function body:

get "/greet/:name" do
  text(conn, "Hello #{name}")
end

You can also access named parameters via conn.params and conn.path_params:

get "/law-of-identity/:value" do
  text(conn, "#{conn.params["name"]} == #{conn.path_params["name"]}")
end

Route patterns may also include glob-like patterns to match trailing segments:

get "/hello/*glob" do
  text(conn, "trailing: #{glob}")
end

Route patterns may also utilize query parameters:

get "/posts" do
  # matches "GET /posts?title=foo&author=bar"
  
  # access via conn.params
  title = conn.params["title"]

  # also can access via conn.query_params
  author = conn.query_params["author"]
end

Static Files

Static files are served from the priv/static directory under the root request path (/) automatically via Plug.Static.

You can override the defaults by plugging it yourself:

plug Plug.Static,
  at: "/public",
  from: "priv/other/path"

Alternatively, you can disable it entirely:

set :serve_static, false

View / Templates

You can render a template with render:

get "/" do
  render(conn, "index.html")
end

This renders templates/index.html.eex.

Templates take a second argument, the options keyword list.

get "/" do
  render(conn, "index.html", layout: :post)
end

This will render templates/index.html.eex embedded in the templates/post.html.eex (default is templates/layout.html.eex, if it exists).