Ruby on Rails Q & A


How to implement Single Sign-On (SSO) in Rails?

Single Sign-On (SSO) is a user authentication process that allows a user to access multiple applications using one set of credentials. Implementing SSO in Rails can improve user experience and manage centralized user authentication across multiple systems. Here’s a basic overview of how to implement SSO in Rails:


  1. Choose an SSO Strategy: The first decision to make is whether to be the identity provider (IDP) yourself or rely on a third-party IDP. Common third-party providers include Okta, Auth0, and Google.


  1. Gem Dependencies: Depending on your strategy, various gems might be helpful. For SAML-based SSO, the `ruby-saml` and `devise_saml_authenticatable` gems are commonly used.


  1. Setup Devise: If you’re not already using it, the `devise` gem is a popular authentication solution for Rails. Devise has modules and strategies for many SSO implementations. For example, for OAuth-based SSO, `omniauth` strategies can be integrated with Devise.


  1. Integration:

   – Own IDP: If you decide to be the IDP, you’ll need to set up your Rails app to generate and validate SAML assertions or JWT tokens, depending on your chosen SSO protocol.

   – Third-party IDP: If using a third-party IDP, you’ll set up your Rails app as a service provider (SP). This typically involves exchanging metadata with the IDP, such as URLs and certificates, and setting up endpoints in your app to receive and process SSO responses.


  1. User Data Mapping: When you receive an authentication assertion or token, you’ll often get a set of user attributes. Map these to your application’s user model, creating or updating users as necessary.


  1. Security: Ensure the communication between your application and the IDP is secure. This typically means using HTTPS, validating SAML assertions, or JWT tokens, and occasionally refreshing certificates.


  1. Logging and Monitoring: Due to the critical nature of authentication, ensure that you have adequate logging and monitoring in place. This can help you diagnose issues and detect any malicious activities.


Implementing SSO in Rails can be complex, especially when handling multiple service providers or integrating with legacy systems. Still, the benefits in terms of user experience and centralized user management can be substantial. Always prioritize security and test thoroughly.

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Senior Software Engineer with a focus on remote work. Proficient in Ruby on Rails. Expertise spans y6ears in Ruby on Rails development, contributing to B2C financial solutions and data engineering.