Support for Rails ActionableError

lib/better_errors/error_page.rb

@@ -28,6 +28,11 @@ def id
 
     def render(template_name = "main")
       binding.eval(self.class.template(template_name).src)
+    rescue => e
+      # Fix the backtrace, which doesn't identify the template that failed (within Better Errors).
+      # We don't know the line number, so just injecting the template path has to be enough.
+      e.backtrace.unshift "#{self.class.template_path(template_name)}:0"
+      raise
     end
 
     def do_variables(opts)
@@ -59,7 +64,19 @@ def exception_type
     end
 
     def exception_message
-      exception.message.lstrip
+      exception.message.strip.gsub(/(\r?\n\s*\r?\n)+/, "\n")
+    end
+
+    def active_support_actions
+      return [] unless defined?(ActiveSupport::ActionableError)
+
+      ActiveSupport::ActionableError.actions(exception.type)
+    end
+
+    def action_dispatch_action_endpoint
+      return unless defined?(ActionDispatch::ActionableExceptions)
+
+      ActionDispatch::ActionableExceptions.endpoint
     end
 
     def application_frames

lib/better_errors/templates/main.erb

@@ -146,14 +146,22 @@
     }
 
     /* Heading */
+    header.exception .fix-actions {
+        margin-top: .5em;
+    }
+
+    header.exception .fix-actions input[type=submit] {
+        font-weight: bold;
+    }
+
     header.exception h2 {
         font-weight: 200;
         font-size: 11pt;
     }
 
     header.exception h2,
     header.exception p {
-        line-height: 1.4em;
+        line-height: 1.5em;
         overflow: hidden;
         white-space: pre;
         text-overflow: ellipsis;
@@ -166,7 +174,7 @@
 
     header.exception p {
         font-weight: 200;
-        font-size: 20pt;
+        font-size: 17pt;
         color: white;
     }
 
@@ -744,6 +752,18 @@
         <header class="exception">
             <h2><strong><%= exception_type %></strong> <span>at <%= request_path %></span></h2>
             <p><%= exception_message %></p>
+            <% unless active_support_actions.empty? %>
+                <div class='fix-actions'>
+                    <% active_support_actions.each do |action, _| %>
+                        <form class="button_to" method="post" action="<%= action_dispatch_action_endpoint %>">
+                            <input type="submit" value="<%= action %>">
+                            <input type="hidden" name="action" value="<%= action %>">
+                            <input type="hidden" name="error" value="<%= exception_type %>">
+                            <input type="hidden" name="location" value="<%= request_path %>">
+                        </form>
+                    <% end %>
+                </div>
+            <% end %>
         </header>
     </div>
 

spec/better_errors/error_page_spec.rb

@@ -37,6 +37,44 @@ module BetterErrors
       expect(response).to have_tag('.exception h2', /ZeroDivisionError/)
     end
 
+    context 'when ActiveSupport::ActionableError is available' do
+      before do
+        skip "ActiveSupport missing on this platform" unless Object.constants.include?(:ActiveSupport)
+        skip "ActionableError missing on this platform" unless ActiveSupport.constants.include?(:ActionableError)
+      end
+
+      context 'when ActiveSupport provides one or more actions for this error type' do
+        let(:exception_class) {
+          Class.new(StandardError) do
+            include ActiveSupport::ActionableError
+
+            action "Do a thing" do
+              puts "Did a thing"
+            end
+          end
+        }
+        let(:exception) { exception_binding.eval("raise exception_class") rescue $! }
+
+        it "includes a fix-action form for each action" do
+          expect(response).to have_tag('.fix-actions') do
+            with_tag('form.button_to')
+            with_tag('form.button_to input[type=submit][value="Do a thing"]')
+          end
+        end
+      end
+
+      context 'when ActiveSupport does provide any actions for this error type' do
+        let(:exception_class) {
+          Class.new(StandardError)
+        }
+        let(:exception) { exception_binding.eval("raise exception_class") rescue $! }
+
+        it "does not include a fix-action form" do
+          expect(response).not_to have_tag('.fix-actions')
+        end
+      end
+    end
+
     context "variable inspection" do
       let(:exception) { exception_binding.eval("raise") rescue $! }