API for OAUTH Login

app/controllers/spree/api/v1/omniauth_callbacks_controller.rb

@@ -0,0 +1,48 @@
+class Spree::Api::V1::OmniauthCallbacksController < Devise::OmniauthCallbacksController
+
+  skip_before_action :verify_authenticity_token
+  before_action :validate_provider, only: :login
+
+  def login
+    authentication = Spree::UserAuthentication.find_by_provider_and_uid(auth_hash['provider'], auth_hash['uid'])
+
+    if authentication.present? && authentication.try(:user).present?
+      access_token(authentication.user)
+    elsif spree_current_user
+      spree_current_user.apply_omniauth(auth_hash)
+      spree_current_user.save!
+      access_token(spree_current_user)
+    else
+      user = Spree::User.find_by_email(auth_hash['info']['email']) || Spree::User.new
+      user.apply_omniauth(auth_hash)
+      if user.save
+        access_token(user).body
+      else
+        render json: { error: I18n.t('spree.user_was_not_valid') }, status: 422 and return
+      end
+    end
+    render json: @token_response.body, status: 200
+  end
+
+  def access_token(user)
+    access_token = Doorkeeper::AccessToken.create!({
+      resource_owner_id: user.id,
+      expires_in: Doorkeeper.configuration.access_token_expires_in,
+      use_refresh_token: Doorkeeper.configuration.refresh_token_enabled?
+    })
+    @token_response = Doorkeeper::OAuth::TokenResponse.new(access_token)
+  end
+
+  def auth_hash
+    params[:omniauth_callback]
+  end
+
+  def validate_provider
+    eligible_providers = SpreeSocial::OAUTH_PROVIDERS.map { |provider| provider[1] if provider[2] == 'true' }.compact
+
+    unless eligible_providers.include?(auth_hash['provider'])
+      render json: { error: I18n.t('devise.omniauth_callbacks.provider_not_found', kind: auth_hash['provider']) },
+             status: 422
+    end
+  end
+end

config/locales/en.yml

@@ -3,6 +3,7 @@ en:
   devise:
     omniauth_callbacks:
       success: "You are now signed in with your %{kind} account."
+      provider_not_found: "Could not authenticate you from %{kind} becasue the provider is invalid"
   spree:
     environment: Environment
     user_was_not_valid: User was not valid.

config/routes.rb

@@ -11,4 +11,12 @@
   namespace :admin do
     resources :authentication_methods
   end
+
+  namespace :api, defaults: { format: 'json' } do
+    namespace :v1 do
+      devise_scope :spree_user do
+        post '/spree_oauth/social_login/:provider', to: 'omniauth_callbacks#login'
+      end
+    end
+  end
 end