Plug

Plug[edit]

Plug logo

Plug is a specification and a set of libraries that provides a common interface for building modular and composable web applications in the Elixir programming language. It serves as the foundation for building web servers, middleware, and other HTTP-related components.

Features[edit]

Plug offers various features that make it a popular choice for web development in Elixir. These features include:

Modularity: Plug allows developers to break down their applications into small, reusable components called plugs. Plugs can be combined and composed to build complex web applications.

Middleware Pipeline: With Plug, developers can define a pipeline through which incoming requests flow. Each plug in the pipeline can perform specific tasks such as authentication, request parsing, response formatting, and more.

Adapters: Plug supports various adapters that allow developers to use their preferred web servers, including Cowboy, Emiller, and Phoenix.

Architecture[edit]

File:Plug-Architecture.png

Plug Architecture Diagram

Plug follows a simple and straightforward architecture. It consists of three main components:

Connection: The connection represents an incoming request and the associated response. It contains information about the request method, headers, cookies, and more.

Plugs: Plugs are the building blocks of a Plug application. They are intermediary functions that process the connection and modify it as it flows through the pipeline. Plugs can be divided into two categories: function plugs and module plugs.

Router: The router is responsible for mapping incoming requests to the appropriate plugs based on the requested path, method, or any other criteria.

Getting Started[edit]

To get started with Plug, follow these steps:

Install the necessary dependencies by adding the Plug package to your project's mix.exs file.
Import the Plug package into your module using `use Plug.Router`.
Define your plugs and routes inside the module.
Start the server using `Plug.Adapters.Cowboy.http`.

Below is an example of a basic Plug application:

```elixir defmodule MyApp do

 use Plug.Router

 plug :hello_world

 get "/" do
   send_resp(conn, 200, "Hello, World!")
 end

 def hello_world(conn, _opts) do
   IO.puts "Running hello_world plug"
   conn
 end

end

Start the server

MyApp.start_link ```

Additional Resources[edit]

To learn more about Plug and its capabilities, consider exploring the following topics on this wiki:

For in-depth tutorials and case studies using Plug, please refer to the Tutorials and Case Studies sections of this wiki (future articles).

External Links[edit]