I was curious what’s happening under the hood when facebook authentication is enabled. I specified some breakpoints in my RubyMine to find out in which order the particular methods are called.
The integration of Facebook consists of these steps: (for more information read https://github.com/plataformatec/devise/wiki/OmniAuth:-Overview):
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adding some gems to Gemfile:
#facebook integration gem 'omniauth' gem 'omniauth-facebook' gem 'omniauth-twitter' gem 'omniauth-linkedin'
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Adding new columns to the table:
bundle install rails g migration AddColumnsToUsers provider uid #note: name is already there rake db:migrate
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make the new columns accessible (for mass assignment):
# User model attr_accessible :provider, :uid
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extending config by adding the facebook configuration:
# initializers/devise.rb: # require the gem and add it to the config! require "omniauth-facebook" config.omniauth :facebook, "5745245454154", "5ecd0a644303fab5c19dfdfdf383d06", #your APP_ID and APP_SECRET #for heroku necessary (development env. works as well) {:strategy_class => OmniAuth::Strategies::Facebook, :scope => 'email, offline_access', :client_options => {:ssl => {:ca_file => '/usr/lib/ssl/certs/ca-certificates.crt'}}} -
user model must have to class instance methods (see link above):
#### User model must have: find_for_facebook_oauth find_in_session
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User model must make itself “omniauthable”:
devise : omniauthable, : omniauth_providers => [:facebook]
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we need an additional controller for handling authentication provider method (facebook, twitter, …)
#### Users controller must have a "sub controller": Users::OmniauthCallbacksController with facebook method.
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we actually don’t need to add a link any view. The links are rendered automatically in this partial:
/devise/shared/_links.html.erb partial
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routes.rb file must be updated accordingly:
devise_for :users, :controllers => { : omniauth_callbacks => "users/omniauth_callbacks" } resources :users
When everything is in place I can start a short debug session just to understand what’s going on and where RoR will step in.
I think the content of the image is self-explanatory. Devise maps the particular URLs to the actions in the controllers this way:
root / home#index
root / home#index
new_user_session GET /users/sign_in(.:format) devise/sessions#new
user_session POST /users/sign_in(.:format) devise/sessions#create
destroy_user_session DELETE /users/sign_out(.:format) devise/sessions#destroy
user_password POST /users/password(.:format) devise/passwords#create
new_user_password GET /users/password/new(.:format) devise/passwords#new
edit_user_password GET /users/password/edit(.:format) devise/passwords#edit
PUT /users/password(.:format) devise/passwords#update
cancel_user_registration GET /users/cancel(.:format) devise/registrations#cancel
user_registration POST /users(.:format) devise/registrations#create
new_user_registration GET /users/sign_up(.:format) devise/registrations#new
edit_user_registration GET /users/edit(.:format) devise/registrations#edit
PUT /users(.:format) devise/registrations#update
DELETE /users(.:format) devise/registrations#destroy
user_omniauth_authorize GET|POST /users/auth/:provider(.:format) users/omniauth_callbacks#passthru {:provider=>/facebook/}
user_omniauth_callback GET|POST /users/auth/:action/callback(.:format) users/omniauth_callbacks#(?-mix:facebook)
users GET /users(.:format) users#index
POST /users(.:format) users#create
new_user GET /users/new(.:format) users#new
edit_user GET /users/:id/edit(.:format) users#edit
user GET /users/:id(.:format) users#show
PUT /users/:id(.:format) users#update
DELETE /users/:id(.:format) users#destroy
