Provide router constraints

Adds SignedInConstraint and SignedOutConstraint, useful from the Rails
router. For example, to redirect admins to their admin dashboard as the
home page:

    constraints(SignedInConstraint.new {|user| user.admin?}) do
      root :to => 'admins/dashboard#index'
    end

README.md

@@ -210,7 +210,34 @@ For example:
     config.password_strategy = Clearance::PasswordStrategies::SHA1
     # Blowfish
     config.password_strategy = Clearance::PasswordStrategies::Blowfish
-
+
+
+Routing Constraints
+-------------------
+
+Clearance ships with Rails [routing constraints](http://guides.rubyonrails.org/routing.html#advanced-constraints).
+These allow you to check if a user is signed in or signed out before they hit your controller - the check is moved down the stack.
+You can use them like this:
+
+    SweetBlog::Application.routes.draw do
+      # Signed-in admin users use this root path
+      constraints(Clearance::Constraints::SignedIn.new {|user| user.admin?}) do
+        root :to => 'admins/dashboard#index'
+      end
+
+      # Signed-in non-admin users use this root path
+      constraints(Clearance::Constraints::SignedIn.new) do
+        root :to => 'organizations#show'
+      end
+
+      # Signed-out users users use this fallback root path
+      constraints(Clearance::Constraints::SignedOut.new) do
+        root :to => 'high_voltage/pages#show', :id => 'home'
+      end
+    end
+
+Note that `Clearance::Constraints::SignedIn` yields a signed-in user object so
+that you can perform additional checks.
 
 Optional Cucumber features
 --------------------------

gemfiles/3.1.4.gemfile.lock

@@ -1,5 +1,5 @@
 PATH
-  remote: /home/mike/clearance
+  remote: /Users/gabe/thoughtbot/open-source/clearance
   specs:
     clearance (0.16.2)
       diesel (~> 0.1.5)

gemfiles/3.2.3.gemfile.lock

@@ -1,5 +1,5 @@
 PATH
-  remote: /home/mike/clearance
+  remote: /Users/gabe/thoughtbot/open-source/clearance
   specs:
     clearance (0.16.2)
       diesel (~> 0.1.5)

lib/clearance.rb

@@ -5,3 +5,4 @@
 require 'clearance/user'
 require 'clearance/engine'
 require 'clearance/password_strategies'
+require 'clearance/constraints'

lib/clearance/constraints.rb

@@ -0,0 +1,2 @@
+require 'clearance/constraints/signed_in'
+require 'clearance/constraints/signed_out'

lib/clearance/constraints/signed_in.rb

@@ -0,0 +1,28 @@
+module Clearance
+  module Constraints
+    class SignedIn
+      def initialize(&block)
+        @block = block || lambda { |user| true }
+      end
+
+      def matches?(request)
+        @request = request
+        signed_in? && current_user_fulfills_additional_requirements?
+      end
+
+      private
+
+      def signed_in?
+        @request.env[:clearance].signed_in?
+      end
+
+      def current_user_fulfills_additional_requirements?
+        @block.call(current_user)
+      end
+
+      def current_user
+        @request.env[:clearance].current_user
+      end
+    end
+  end
+end

lib/clearance/constraints/signed_out.rb

@@ -0,0 +1,9 @@
+module Clearance
+  module Constraints
+    class SignedOut
+      def matches?(request)
+        request.env[:clearance].signed_out?
+      end
+    end
+  end
+end

lib/clearance/session.rb

@@ -10,6 +10,10 @@ def signed_in?
       current_user.present?
     end
 
+    def signed_out?
+      ! signed_in?
+    end
+
     def current_user
       @current_user ||= with_remember_token do |token|
         Clearance.configuration.user_model.find_by_remember_token(token)

spec/clearance/constraints/signed_in_spec.rb

@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+describe Clearance::Constraints::SignedIn do
+  it 'returns true when user is signed in' do
+    user = create(:user)
+
+    signed_in_constraint = Clearance::Constraints::SignedIn.new
+    signed_in_constraint.matches?(request_with_remember_token(user.remember_token)).should be_true
+  end
+
+  it 'returns false when user is not signed in' do
+    signed_in_constraint = Clearance::Constraints::SignedIn.new
+    signed_in_constraint.matches?(request_without_remember_token).should be_false
+  end
+
+  it 'yields a signed-in user to a provided block' do
+    user = create(:user, :email => 'before@example.com')
+    signed_in_constraint = Clearance::Constraints::SignedIn.new do |user|
+      user.update_attribute(:email, 'after@example.com')
+    end
+
+    signed_in_constraint.matches?(request_with_remember_token(user.remember_token))
+    user.reload.email.should == 'after@example.com'
+  end
+
+  it 'does not yield a user if they are not signed in' do
+    user = create(:user, :email => 'before@example.com')
+
+    signed_in_constraint = Clearance::Constraints::SignedIn.new do |user|
+      user.update_attribute(:email, 'after@example.com')
+    end
+
+    signed_in_constraint.matches?(request_without_remember_token)
+    user.reload.email.should == 'before@example.com'
+  end
+
+  it 'matches if the user-provided block returns true' do
+    user = create(:user)
+
+    signed_in_constraint = Clearance::Constraints::SignedIn.new { |user| true }
+
+    signed_in_constraint.matches?(request_with_remember_token(user.remember_token)).should be_true
+  end
+
+  it 'does not match if the user-provided block returns false' do
+    user = create(:user)
+
+    signed_in_constraint = Clearance::Constraints::SignedIn.new { |user| false }
+
+    signed_in_constraint.matches?(request_with_remember_token(user.remember_token)).should be_false
+  end
+end

spec/clearance/constraints/signed_out_spec.rb

@@ -0,0 +1,15 @@
+require 'spec_helper'
+
+describe Clearance::Constraints::SignedOut do
+  it 'returns true when user is signed out' do
+    signed_out_constraint = Clearance::Constraints::SignedOut.new
+    signed_out_constraint.matches?(request_without_remember_token).should be_true
+  end
+
+  it 'returns false when user is not signed out' do
+    user = create(:user)
+
+    signed_out_constraint = Clearance::Constraints::SignedOut.new
+    signed_out_constraint.matches?(request_with_remember_token(user.remember_token)).should be_false
+  end
+end

spec/clearance/session_spec.rb

@@ -18,14 +18,14 @@
     env = env_with_remember_token("bogus")
 
     session = Clearance::Session.new(env)
-    session.should_not be_signed_in
+    session.should be_signed_out
     session.current_user.should be_nil
   end
 
   it "returns nil without a remember token" do
     env = env_without_remember_token
     session = Clearance::Session.new(env)
-    session.should_not be_signed_in
+    session.should be_signed_out
     session.current_user.should be_nil
   end
 

spec/support/request_with_remember_token.rb

@@ -0,0 +1,17 @@
+module RememberTokenHelpers
+  def request_with_remember_token(remember_token)
+    cookies = {'action_dispatch.cookies' => {
+      Clearance::Session::REMEMBER_TOKEN_COOKIE => remember_token
+    }}
+    env = { :clearance => Clearance::Session.new(cookies) }
+    Rack::Request.new(env)
+  end
+
+  def request_without_remember_token
+    request_with_remember_token(nil)
+  end
+end
+
+RSpec.configure do |config|
+  config.include RememberTokenHelpers
+end