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Elixir Cookbook

You're reading from   Elixir Cookbook Unleash the full power of programming in Elixir with over 60 incredibly effective recipes

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Product type Paperback
Published in Feb 2015
Publisher Packt
ISBN-13 9781784397517
Length 236 pages
Edition 1st Edition
Languages
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Author (1):
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Paulo Pereira Paulo Pereira
Author Profile Icon Paulo Pereira
Paulo Pereira
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Toc

Table of Contents (11) Chapters Close

Preface 1. Command Line 2. Data Types and Structures FREE CHAPTER 3. Strings and Binaries 4. Modules and Functions 5. Processes and Nodes 6. OTP – Open Telecom Platform 7. Cowboy and Phoenix 8. Interactions A. Installation and Further Reading Index

Implementing topics


Topics in Phoenix are a form of implementing the publisher-subscriber pattern.

In this recipe, we will create a simple counter in a form of a function that will subscribe a channel.

In TodosController, we will broadcast an event every time a request is made to the index action. The counter will then receive the notification and will output a message to the console with the number of times the action was called.

Getting ready

To get started, we will take the code resulting from the previous recipe. Open a code editor and prepare to add pub/sub to the Phoenix application.

How to do it…

To implement topics in the Phoenix application, follow these steps:

  1. Edit TodoController to make it look like this:

    defmodule Todo.TodosController do
      use Phoenix.Controller
    
      plug :action
      plug :render
    
      def index(conn, _params) do
        todos = [%{id: 1, task: "Write the other controller actions!", created_at: "2014-12-13", status: "pending"}, %{id: 2, task: "Create Views", created_at: "2014-12...
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