Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/nsarno/knock

Seamless JWT authentication for Rails API
https://github.com/nsarno/knock

Last synced: 3 months ago
JSON representation

Seamless JWT authentication for Rails API

Awesome Lists containing this project

README

        

## DISCLAIMER

This project is not being maintained and I don't recommend using it in its current form.
As an alternative, I recommend using the [jwt](https://github.com/jwt/ruby-jwt) gem directly.

# knock

[![Gem Version](https://badge.fury.io/rb/knock.svg)](http://badge.fury.io/rb/knock)
[![Build Status](https://travis-ci.org/nsarno/knock.svg)](https://travis-ci.org/nsarno/knock)
[![Code Climate](https://codeclimate.com/github/nsarno/knock/badges/gpa.svg)](https://codeclimate.com/github/nsarno/knock)

Seamless JWT authentication for Rails API

## Description

Knock is an authentication solution for Rails API-only application based on JSON Web Tokens.

## Getting Started

### Installation

Add this line to your application's Gemfile:

```ruby
gem 'knock'
```

Then execute:

$ bundle install

### Requirements

Knock makes one assumption about your user model:

It must have an `authenticate` method, similar to the one added by [has_secure_password](http://api.rubyonrails.org/classes/ActiveModel/SecurePassword/ClassMethods.html#method-i-has_secure_password).

```ruby
class User < ActiveRecord::Base
has_secure_password
end
```

Using `has_secure_password` is recommended, but you don't have to as long as your user model implements an `authenticate` instance method with the same behavior.

### Usage

Include the `Knock::Authenticable` module in your `ApplicationController`

```ruby
class ApplicationController < ActionController::API
include Knock::Authenticable
end
```

You can now protect your resources by calling `authenticate_user` as a before_action
inside your controllers:

```ruby
class SecuredController < ApplicationController
before_action :authenticate_user

def index
# etc...
end

# etc...
end
```

You can access the current user in your controller with `current_user`.

If no valid token is passed with the request, Knock will respond with:

```
head :unauthorized
```

You can modify this behaviour by overriding `unauthorized_entity` in your controller.

You also have access directly to `current_user` which will try to authenticate or return `nil`:

```ruby
def index
if current_user
# do something
else
# do something else
end
end
```

_Note: the `authenticate_user` method uses the `current_user` method. Overwriting `current_user` may cause unexpected behaviour._

You can do the exact same thing for any entity. E.g. for `Admin`, use `authenticate_admin` and `current_admin` instead.

If you're using a namespaced model, Knock won't be able to infer it automatically from the method name. Instead you can use `authenticate_for` directly like this:

```ruby
class ApplicationController < ActionController::Base
include Knock::Authenticable

private

def authenticate_v1_user
authenticate_for V1::User
end
end
```

```ruby
class SecuredController < ApplicationController
before_action :authenticate_v1_user
end
```

Then you get the current user by calling `current_v1_user` instead of `current_user`.

### Configuration

#### In the entity model

The entity model (e.g. `User`) can implement specific methods to provide
customization over different parts of the authentication process.

- **Find the entity when creating the token (when signing in)**

By default, Knock tries to find the entity by email. If you want to modify this
behaviour, implement within your entity model a class method `from_token_request`
that takes the request in argument.

E.g.

```ruby
class User < ActiveRecord::Base
def self.from_token_request request
# Returns a valid user, `nil` or raise `Knock.not_found_exception_class_name`
# e.g.
# email = request.params["auth"] && request.params["auth"]["email"]
# self.find_by email: email
end
end
```

- **Find the authenticated entity from the token payload (when authenticating a request)**

By default, Knock assumes the payload as a subject (`sub`) claim containing the entity's id
and calls `find` on the model. If you want to modify this behaviour, implement within
your entity model a class method `from_token_payload` that takes the
payload in argument.

E.g.

```ruby
class User < ActiveRecord::Base
def self.from_token_payload payload
# Returns a valid user, `nil` or raise
# e.g.
# self.find payload["sub"]
end
end
```

- **Modify the token payload**

By default the token payload contains the entity's id inside the subject (`sub`) claim.
If you want to modify this behaviour, implement within your entity model an instance method
`to_token_payload` that returns a hash representing the payload.

E.g.

```ruby
class User < ActiveRecord::Base
def to_token_payload
# Returns the payload as a hash
end
end
```

- **Token Lifetime**

By default the generated tokens will be valid, after generated, for 1 day.
You can change it in the Knock configuration file (config/knock.rb),
setting the desired lifetime:

E.g.

```ruby
Knock.token_lifetime = 3.hours
```

If you are generating tokens for more than one entity, you can pass
each lifetime in a hash, using the entities class names as keys, like:

E.g.

```ruby
# How long before a token is expired. If nil is provided,
# token will last forever.
Knock.token_lifetime = {
user: 1.day
admin: 30.minutes
}
```

#### In the initializer

Read [lib/knock.rb](https://github.com/nsarno/knock/blob/master/lib/knock.rb) to learn about all the possible configuration options and their default values.

You can create an initializer like in the example below:

Inside `config/initializers/knock.rb`

```ruby
Knock.setup do |config|
config.token_lifetime = 1.hour

# For Auth0
config.token_audience = -> { Rails.application.secrets.auth0_client_id }
config.token_secret_signature_key = -> { JWT.base64url_decode Rails.application.secrets.auth0_client_secret }
end
```

### Authenticating from a web or mobile application

Example request to get a token from your API:

```
POST /user_token
{"auth": {"email": "[email protected]", "password": "secret"}}
```

Example response from the API:

```
201 Created
{"jwt": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9"}
```

To make an authenticated request to your API, you need to pass the token via the request header:

```
Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9
GET /my_resources
```

Knock responds with a `404 Not Found` when the user cannot be found or the password is invalid. This is a security best practice to avoid giving away information about the existence or not of a particular user.

**NB:** HTTPS should always be enabled when sending a password or token in your request.

### Authenticated tests

To authenticate within your tests:

1. Create a valid token
2. Pass it in your request

e.g.

```ruby
class SecuredResourcesControllerTest < ActionDispatch::IntegrationTest
def authenticated_header
token = Knock::AuthToken.new(payload: { sub: users(:one).id }).token

{
'Authorization': "Bearer #{token}"
}
end

it 'responds successfully' do
get secured_resources_url, headers: authenticated_header

assert_response :success
end
end
```

#### Without ActiveRecord

If no ActiveRecord is used, then you will need to specify what Exception will be used when the user is not found with the given credentials.

```ruby
Knock.setup do |config|

# Exception Class
# ---------------
#
# Configure the Exception to be used (raised and rescued) for User Not Found.
# note: change this if ActiveRecord is not being used.
#
# Default:
config.not_found_exception_class_name = 'MyCustomException'
end
```

### Algorithms

The JWT spec supports different kind of cryptographic signing algorithms.
You can set `token_signature_algorithm` to use the one you want in the
initializer or do nothing and use the default one (HS256).

You can specify any of the algorithms supported by the
[jwt](https://github.com/jwt/ruby-jwt) gem.

If the algorithm you use requires a public key, you also need to set
`token_public_key` in the initializer.

## CORS

To enable cross-origin resource sharing, check out the [rack-cors](https://github.com/cyu/rack-cors) gem.

## Related links

- [10 things you should know about tokens](https://auth0.com/blog/2014/01/27/ten-things-you-should-know-about-tokens-and-cookies/)

## Contributing

1. Fork it ( https://github.com/nsarno/knock/fork )
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request

## License

MIT