Using Omnicontacts to get mail contacts from Google

Today, when I'm working on company, my colleague asked me: "Do you use Omnicontacts gem to get mail contacts from Google?". After 30 minutes research about this gem, now I'll write a post "Using Omnicontacts to get mail contacts from Google".

• First, create new rails app:

	mkdir omnicontacts
	cd omnicontacts/
	rails new .

• After run command bundle install, let's add OmniContacts into Gemfile as a dependency:

	gem 'omnicontacts'

bundle install again.

• You need generate a controller to handle callback returned from Google.

rails g controller main index contact

	class MainController < ApplicationController
		def index
  		end
		def contact
		end
	end

• As for Omniauth, let's go to /config/initializers/ directory and create new file omnicontacts.rb

	require 'omnicontacts'

	Rails.application.middleware.use OmniContacts::Builder do
  		importer :gmail, "client_id", "client_secret, {:redirect_path => "/oauth2callback", :ssl_ca_path => "/etc/ssl/certs/curl-ca-bundle.crt"}
	end

To add client_id and client_secret, please access Google API Console and Create new Client ID

• After generated main_controller, let's update the routes file:

	Omnicontacts::Application.routes.draw do
		match "/contacts/:importer/callback" => "main#index", :via => [:get]
		match "/oauth2callback" => "main#contact", :via => [:get]
		# You can have the root of your site routed with "root"
 		root 'main#index'
	end

• The list of contacts will be accesses via the omnicontacts.contact key in the environment hash. So, please edit the main_controller file:

	class MainController < ApplicationController
		def index
  		end
		def contact
			@contacts = request.env['omnicontacts.contacts']
			respond_to do |format|
      			format.html 
    		end
		end
	end

• After that, we need edit two files in Views folder

/main/index.html.erb

	<h2>OmniContacts Example</h2>

	<a href="/contacts/gmail">Gmail</a>

/main/contact.html.erb

	<% unless @contacts.nil?%>
  		<% @contacts.each do |c|%>
  			<ul>
    			<li><%= c[:name]%> :  <%= c[:email]%></li>
  			</ul> 
  		<%end%>
	<%end%>

• Done, now you can run rails s and access to http://localhost:3000.

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You can refer example at link: http://omnicontactsvinhnguyen.herokuapp.com/ or https://github.com/vinhnguyenleasnet/omnicontactvinhnguyen