Francisco Fullenkamp ffullenk

Realtime Notifications with ActionCable

In this episode we're going to be adding realtime notifications into your app using ActionCable. We've talked about notifications a few times in the past and we used AJAX polling for that. 95% of the time, polling is the solution that would be recommended for it.

But if you're looking for a good introduction into ActionCable then this is a decent one because we're only really using it for one way from the server side to the client side.

Getting started

So to get started we're starting with an app that has Bootstrap installed and then we created a Main controller with an index view which is where we will list our Notifications as for this example.

Before we generate our channels let's install a few things

This was super annoying so i decided to write it down.

I needed to add some data attributes to a simple_form input(f.input :people, as: :select) and also maintain the bootstrap classes

Here's how i solved it:

<%= f.input :car_id, label: 'Select a Car' do %>
    <%= f.select :car_id, @cars.map { |car| [car.name, car.id, {'data-car-price' => car.current_price}] }, {include_blank: true}, {class: 'form-control'} %>
&lt;% end %&gt;

Pry Cheat Sheet

Youtube Tutorial 2013

Command Line

pry -r ./config/app_init_file.rb - load your app into a pry session (look at the file loaded by config.ru)
pry -r ./config/environment.rb - load your rails into a pry session

Debugger

	#!/usr/bin/env ruby

	require 'openssl'
	require 'time'

	begin
	require 'origami'
	rescue LoadError
	abort 'origami not installed: gem install origami'
	end

	<VirtualHost :80 :443>
	# Domain
	ServerName servername.domain

	SSLEngine On
	SSLProxyEngine On
	# Path to SSL CRT file
	SSLCertificateFile /etc/apache2/ssl/apache.crt
	# Path to SSL KEY file
	SSLCertificateKeyFile /etc/apache2/ssl/apache.key

	#!/usr/bin/env bash

	# Clear out all previous attempts
	rm -rf "/tmp/source-git/"

	# Get the dependencies for git, then get openssl
	sudo apt-get install build-essential fakeroot dpkg-dev -y
	sudo apt-get build-dep git -y
	sudo apt-get install libcurl4-openssl-dev -y
	mkdir -p "/tmp/source-git/"

	class NotificationsController < ApplicationController
	def notify_me

	# Rails reserve a db connection from connection pool for each request, lets put it back into connection pool.
	ActiveRecord::Base.clear_active_connections!

	# required header
	response.headers['Content-Type'] = 'text/event-stream'

	sse = ActionController::Live::SSE.new(response.stream)

	CREATE OR REPLACE FUNCTION clone_schema(source_schema text, dest_schema text) RETURNS void AS
	$$

	DECLARE
	object text;
	buffer text;
	default_ text;
	column_ text;
	constraint_name_ text;
	constraint_def_ text;

	class TestMailer < ActionMailer::Base

	def email
	headers['X-Tag-Via-Hash-Access'] = 'value'
	headers 'X-Tag-Via-Headers-Method' => 'value'

	mail(to: '[email protected]', from: '[email protected]', subject: 'Headers test') do \|format\|
	format.text { render text: 'Headers test' }
	end

	# config/initializers/carrierwave_direct.rb
	require "carrierwave_direct"

	module CarrierWaveDirect
	module SignatureFixMonkeyPatch
	def policy(options = {})
	options[:expiration] \|\|= upload_expiration
	options[:min_file_size] \|\|= min_file_size
	options[:max_file_size] \|\|= max_file_size