Class: Rack::JsonWebTokenAuth

Inherits:
Object
  • Object
show all
Includes:
Contracts::Core
Defined in:
lib/rack/json_web_token_auth.rb,
lib/rack/json_web_token_auth/version.rb,
lib/rack/json_web_token_auth/resource.rb,
lib/rack/json_web_token_auth/resources.rb

Overview

Rack Middleware for JSON Web Token Authentication

Defined Under Namespace

Classes: Resource, Resources

Constant Summary collapse

C = 
Contracts
ENV_KEY = 
'jwt.claims'.freeze
PATH_INFO_HEADER_KEY = 
'PATH_INFO'.freeze
VERSION = 
'0.1.0'.freeze

Instance Method Summary collapse

Constructor Details

#initialize(app, &block) ⇒ JsonWebTokenAuth

Returns a new instance of JsonWebTokenAuth.



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# File 'lib/rack/json_web_token_auth.rb', line 20

def initialize(app, &block)
  @app = app
  # execute the block methods provided in the context of this class
  instance_eval(&block)
end

Instance Method Details

#all_resources ⇒ Object 



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# File 'lib/rack/json_web_token_auth.rb', line 103

def all_resources
  @all_resources ||= []
end

#call(env) ⇒ Object 



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# File 'lib/rack/json_web_token_auth.rb', line 45

def call(env)
  begin
    resource = resource_for_path(env[PATH_INFO_HEADER_KEY])

    if resource.public_resource?
      # whitelisted as `unsecured`. skip all token authentication.
      @app.call(env)
    elsif resource.nil?
      # no matching `secured` or `unsecured` resource.
      # fail-safe with 401 unauthorized
      raise 'No resource for path defined. Deny by default.'
    else
      # a `secured` resource, validate the token to see if authenticated

      # Test that `env` has a well formed Authorization header
      unless Contract.valid?(env, C::RackRequestHttpAuth)
        raise 'malformed Authorization header or token'
      end

      # Extract the token from the 'Authorization: Bearer token' string
      token = C::BEARER_TOKEN_REGEX.match(env['HTTP_AUTHORIZATION'])[1]

      # Verify the token and its claims are valid
      jwt_opts = resource.opts[:jwt]
      jwt = ::JwtClaims.verify(token, jwt_opts)

      # JwtClaims.verify returns a JWT claims set hash, if the
      # JWT Message Authentication Code (MAC), or signature,
      # are verified and the registered claims are also verified.
      if Contract.valid?(jwt, C::HashOf[ok: C::HashOf[Symbol => C::Any]])
        # Authenticated! Pass all claims into the app env for app use
        # with the hash keys converted to strings to match Rack env.
        env[ENV_KEY] = Hashie.stringify_keys(jwt[:ok])
      elsif Contract.valid?(jwt, C::HashOf[error: C::ArrayOf[Symbol]])
        # a list of any registered claims that fail validation, if the JWT MAC is verified
        raise "invalid JWT claims : #{jwt[:error].sort.join(', ')}"
      elsif Contract.valid?(jwt, C::HashOf[error: 'invalid JWT'])
        # the JWT MAC is not verified
        raise 'invalid JWT'
      elsif Contract.valid?(jwt, C::HashOf[error: 'invalid input'])
        # otherwise
        raise 'invalid JWT input'
      else
        raise 'unhandled JWT error'
      end

      @app.call(env)
    end
  rescue StandardError => e
    body = e.message.nil? ? 'Unauthorized' : "Unauthorized : #{e.message}"
    headers = { 'WWW-Authenticate' => 'Bearer error="invalid_token"',
                'Content-Type' => 'text/plain',
                'Content-Length' => body.bytesize.to_s }
    [401, headers, [body]]
  end
end

#resource_for_path(path_info) ⇒ Object 



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# File 'lib/rack/json_web_token_auth.rb', line 108

def resource_for_path(path_info)
  all_resources.each do |r|
    if found = r.resource_for_path(path_info)
      return found
    end
  end
  nil
end

#secured(&block) ⇒ Object 



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# File 'lib/rack/json_web_token_auth.rb', line 27

def secured(&block)
  resources = Resources.new(public_resource: false)
  # execute the methods in the 'secured' block in the context of
  # a new Resources object
  resources.instance_eval(&block)
  all_resources << resources
end

#unsecured(&block) ⇒ Object 



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# File 'lib/rack/json_web_token_auth.rb', line 36

def unsecured(&block)
  resources = Resources.new(public_resource: true)
  # execute the methods in the 'unsecured' block in the context of
  # a new Resources object
  resources.instance_eval(&block)
  all_resources << resources
end