> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rownd.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Ruby on Rails
> Ruby on Rails SDK reference
Rownd's support for Ruby on Rails is powered by our Ruby gem named
`devise-rownd`. This gem is an implementation of a custom strategy for the
popular [Devise](https://github.com/heartcombo/devise) framework. It works in
tandem with the Rownd Hub, a javascript snippet embedded in your website. With
this gem installed, Rownd handles all aspects of user authentication and gives
you the tools to customize the user experience on your site.
## Installation
Add this line to your application's `Gemfile`:
```rb theme={null}
gem 'devise-rownd'
```
And then execute:
```
$ bundle
```
Or install it yourself as:
```bash theme={null}
$ gem install devise-rownd
```
### Mount the Engine
Add this to your `config/routes.rb` file
```rb theme={null}
mount Devise::Rownd::Engine, at: '/api/auth/rownd'
```
### Rownd Hub
Follow [these instructions](/sdk-reference/web/javascript--browser)
to install the Rownd Hub. You'll want to ensure it runs on every page of your
application, so be sure to add it as a common in your Rails JS packs. Here's the
easiest way to do that:
1. Create a new file in your JS packs directory called `rownd.js` and paste the
JS snippet that you got from the instructions listed above.
2. 2. Add the following API callbacks to your Javascript:
```js theme={null}
_rphConfig.push([
"setPostAuthenticationApi",
{
method: "post",
url: "/api/auth/rownd/authenticate",
},
]);
_rphConfig.push([
"setPostSignOutApi",
{
method: "POST",
url: "/api/auth/rownd/sign_out",
},
]);
_rphConfig.push([
"setPostUserDataUpdateApi",
{
method: "POST",
url: "/api/auth/rownd/update_data",
},
]);
```
The path prefix `/api/auth/rownd` must match the `Devise::Rownd::Engine` mount
path that you specified in your Rails routes
1. Finally, include the Javascript pack in your application layout.
```js theme={null}
<%= show_rownd_signin_if_required %>
<%= yield %>
<%= javascript_pack_tag 'rownd', 'data-turbolinks-track': 'reload' %>
```
There are two key pieces that you must include in the layout:
`<%= show_rownd_signin_if_required %>` This renders the Rownd sign-in modal to
prompt the user for authentication when your app explicitly requires it in a
controller
`<%= javascript_pack_tag 'rownd', 'data-turbolinks-track': 'reload' %>` Tells
Rails to include the `rownd` Javascript pack. We also tell Turbolinks to include
the script on page reloads
## Usage
For this to work, you need to define these key environment variables:
* `ROWND_APP_KEY` - Your Rownd application key
* `ROWND_APP_SECRET` - Your Rownd application secret
You can get all of these values from the [Rownd Platform](https://app.rownd.io)
### Users
This gem provides a new Devise module named `:rownd_authenticatable`. In your
`user` model, you can tell Devise to use it like this:
```rb theme={null}
class User < ApplicationRecord
devise :rownd_authenticatable
...
end
```
Now, in your `config/routes.rb` file, add the following:
```rb theme={null}
Rails.application.routes.draw do
devise_for :users
...
mount Devise::Rownd::Engine, at: '/api/auth/rownd'
end
...
```
### Require Authentication
You can require authentication on a controller's actions the same way you would
for any Devise strategies.
```rb theme={null}
class MyController < ApplicationController
before_action :authenticate_user!
...
end
```
Now, when a user navigates to a route that requires authentication, Devise will
prompt the user to sign into Rownd if a user is not already signed in.
### Customizing the page using the `current_user`
In any of your controllers, views, or helpers, you have access to the currently
authenticated user via the `current_user` variable. You can use it to customize
your page content like this:
```rb theme={null}
Hello, <%= current_user.first_name %>!
```
The `current_user` object has all of the fields specified in your Rownd
application's schema. If the user doesn't have a value for a particular field,
it will be `nil`
### Extending the `current_user` model
You can extend the `current_user` object by modifying the `Devise::Rownd::User`
class. This can be very helpful if you want to have additional functions that
aggregate data across multiple fields, or perform some logic and return the
result.
For instance, you might want a function called `admin?` that will return if the
current user has an `'admin'` role. To extend the `current_user` object, add a
new initializer in `config/initializers` called `devise_rownd.rb`. In there you
can modify the `Devise::Rownd::User` like this:
```rb theme={null}
Devise::Rownd::User.class_eval do
def admin?
roles&.include?('admin')
end
def display_name
fullname = "#{first_name} #{last_name}"
fullname.present? ? fullname.strip.upcase : email&.upcase
end
...
end
```
Now, you can call things like `current_user.admin?` and
`current_user.display_name`
### Further customization
All of the other Rownd HTML attributes work as well. You can see a full list of
them [here](/rownd/sdk-reference/web/javascript-browser#hooks). This means you
have the ability to customize the page with pure HTML, rather than Ruby code if
you prefer.