Improve enfore_modal method and rescue from it (#98)

README.md

@@ -187,6 +187,12 @@ a href=popover_path(new_post_path, placement: :left)
 
 This will request `new_post_path` and display it left of the anchor thanks to PopperJS.
 
+> [!TIP]
+> If you want to make sure that your modal content is only available if requested through Shimmer, you can use the built in `enfore_modal` method as a `before_action`. It will return a _422 Unprocessable Content_ status if users (or bots) access the page directly.
+> ```rb
+> before_action :enforce_modal, only: [:popover]
+> ```
+
 ### Remote Navigation
 
 Remote navigation takes Hotwire to the next level with built-in navigation actions, integrated with modals and popovers.

lib/shimmer/utils/remote_navigation.rb

@@ -4,6 +4,8 @@ module Shimmer
   module RemoteNavigation
     extend ActiveSupport::Concern
 
+    class RemoteNavigationError < StandardError; end
+
     included do
       def ui
         @ui ||= RemoteNavigator.new(self)
@@ -45,7 +47,17 @@ def render_modal
       end
 
       def enforce_modal
-        raise "trying to render a modal from a regular request" unless shimmer_request?
+        return if shimmer_request?
+
+        raise RemoteNavigationError.new("You may only render a modal from a Shimmer request.")
+      end
+
+      rescue_from RemoteNavigationError do |exception|
+        if Rails.env.development?
+          render plain: exception.message, status: :unprocessable_entity
+        else
+          head :unprocessable_entity
+        end
       end
     end
   end

spec/rails_app/app/controllers/posts_controller.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class PostsController < ApplicationController
+  before_action :enforce_modal, only: [:modal]
+
   def index
     @posts = Post.all
   end
@@ -18,6 +20,9 @@ def create
     end
   end
 
+  def modal
+  end
+
   private
 
   def post_params

spec/rails_app/config/routes.rb

@@ -2,7 +2,11 @@
 
 Rails.application.routes.draw do
   resources :files, only: :show, controller: "shimmer/files"
-  resources :posts
+  resources :posts do
+    collection do
+      get :modal
+    end
+  end
 
   get "styleguide", to: "pages#styleguide"
   root "posts#index"