Strategy to authenticate with PayPal via OmniAuth.

Get your API key at: https://developer.paypal.com/developer/applications/ in the section RESTApps. Note the Client ID and the Client Secret.

Note: You generate separate keys for development (sandbox) and production (live) with each application you register. Use the config Gem to organize your keys and keep them save.

For more details, read the PayPal docs: https://developer.paypal.com/docs/integration/direct/identity/

Add to your Gemfile:

gem "omniauth-paypal-oauth2"

And then execute:

$ bundle

Or install it yourself as:

$ gem install omniauth-paypal-oauth2

• Go to 'https://developer.paypal.com/developer/applications/'
• Select your project.
• Scroll down to 'APP SETTINGS' for each 'SANDBOX' and 'LIVE'.
• Set <YOURDOMAIN>/users/auth/paypal_oauth2/callback as Return URL.
• Make sure "Log In with PayPal" is enabled and Save.
• Go to Credentials, then select the "OAuth consent screen" tab on top, and provide an 'EMAIL ADDRESS' and a 'PRODUCT NAME'
• Wait 10 minutes for changes to take effect.

Here's an example for adding the middleware to a Rails app in config/initializers/omniauth.rb:

Rails.application.config.middleware.use OmniAuth::Builder do
    provider :paypal_oauth2, ENV["PAYPAL_CLIENT_ID"], ENV["PAYPAL_CLIENT_SECRET"], :strategy_class => OmniAuth::Strategies::PayPalOauth2
end

You can now access the OmniAuth PayPal OAuth2 URL: /auth/paypal_oauth2

Note: While developing your application, if you change the scope in the initializer you will need to restart your app server. Remember that either the 'email' or 'profile' scope is required!

If you click from your Applications Dashboard in your Application on "Advanced Options" in the "APP SETTINGS" section and "Log In with PayPal" subsection, you can configure several options:

• Basic authentication: The unique identifier PPID (PayPal ID) is provided. No additional customer information. Not customizable.

• Personal Information:

  • Full name: Permits the Name of the customer.
  • Date of birth: Permits the date of birth of the customer.
  • Age range: Permits an approximate age range of the customer.

• Address Information:

  • Email address: Permits the email address of the customer.
  • Street address: Permits the street address of the customer (Street name, House number).
  • City: Permits the city name where the customer resides.
  • State: Permits the state in which the city is located.
  • Country: Permits the country in which both state and city are located.
  • Zip code: Permits the Zip code of the customer.
  • Phone: Permits the phone number of the customer.

• Account Information:

  • Account status (verified): Permits a boolean which indicates whether the customer is verified by PayPal or not.
  • Account type: Permits a string which indicates the account type of the PayPal customer (e.g.: PERSONAL, BUSINESS).
  • Account creation date: Permits the date on which the PayPal account got created.
  • Time zone: Permits the time zone in which the PayPal customer is located.
  • Locale: Permits a locale string which indicates where the PayPal customer is.
  • Language: Permits the language the customer uses on PayPal.

Here's an example of an authentication hash available in the callback by accessing request.env["omniauth.auth"]:

{
    provider: "paypal",
    uid: "bathjJwvdhKjgfgh8Jd745J7dh5Qkgflbnczd65dfnw",
    info: {
        name: "John Smith",
        email: "[email protected]",
        first_name: "John",
        last_name: "Smith",
        given_name: "John",
        family_name: "Smith",
        location: "Moscow",
        phone: "71234567890"
    },
    credentials: {
        token: "token",
        refresh_token: "refresh_token",
        expires_at: 1355082790,
        expires: true
    },
    extra: {
        account_creation_date: "2008-04-21",
        account_type: "PERSONAL",
        user_id: "https://www.paypal.com/webapps/auth/identity/user/bathjJwvdhKjgfgh8Jd745J7dh5Qkgflbnczd65dfnw",
        address: {
            country: "US",
            locality: "San Jose",
            postal_code: "95131",
            region: "CA",
            street_address: "1 Main St"
        },
        language: "en_US",
        locale: "en_US",
        verified_account: true,
        zoneinfo: "America/Los_Angeles",
        age_range: "31-35",
        birthday: "1982-01-01"
    }
}

For more details see the PayPal List Of Attributes.

First define your application id and secret in config/initializers/devise.rb. Do not use the snippet mentioned in the Usage section.

Configuration options can be passed as the last parameter here as key/value pairs.

require "omniauth-paypal-oauth2"
config.omniauth :paypal_oauth2, "PAYPAL_CLIENT_ID", "PAYPAL_CLIENT_SECRET", :strategy_class => OmniAuth::Strategies::PayPalOauth2, { }

Then add the following to 'config/routes.rb' so the callback routes are defined.

devise_for :users, :controllers => { :omniauth_callbacks => "users/omniauth_callbacks" }

Make sure your model is omniauthable. Generally this is "/app/models/user.rb"

devise :omniauthable, :omniauth_providers => [:paypal_oauth2]

Then make sure your callbacks controller is setup.

class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController
  def paypal_oauth2
      # You need to implement the method below in your model (e.g. app/models/user.rb)
      @user = User.from_omniauth(request.env["omniauth.auth"])

      if @user.persisted?
        flash[:notice] = I18n.t "devise.omniauth_callbacks.success", :kind => "PayPal"
        sign_in_and_redirect @user, :event => :authentication
      else
        session["devise.paypal_data"] = request.env["omniauth.auth"]
        redirect_to new_user_registration_url
      end
  end
end

and bind to or create the user

def self.from_omniauth(access_token)
    data = access_token.info
    user = User.where(:email => data["email"]).first

    # Uncomment the section below if you want users to be created if they don't exist
    # unless user
    #     user = User.create(name: data["name"],
    #        email: data["email"],
    #        password: Devise.friendly_token[0,20]
    #     )
    # end
    user
end

For your views you can login using:

<%= link_to "Sign in with PayPal", user_paypal_oauth2_omniauth_authorize_path %>

<%# Devise prior 4.1.0: %>
<%= link_to "Sign in with PayPal", user_omniauth_authorize_path(:paypal_oauth2) %>

An overview is available at https://github.com/plataformatec/devise/wiki/OmniAuth:-Overview

MIT License

Copyright (c) 2017 Jonas Hübotter

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