Ladybird+LibWeb: Use old error.html template for navigation errors again

Base/res/html/error.html

@@ -19,6 +19,5 @@
             <img src="@resource_directory_url@/icons/32x32/msgbox-warning.png" alt="Warning" width="24" height="24">
             <h1>Failed to load @failed_url@</h1>
         </header>
-        <p>Error: @error@</p>
     </body>
 </html>

Ladybird/Android/src/main/cpp/WebContentService.cpp

@@ -71,6 +71,7 @@ ErrorOr<int> service_main(int ipc_socket, int fd_passing_socket)
     Web::Platform::FontPlugin::install(*new Ladybird::FontPlugin(is_layout_test_mode));
 
     Web::set_resource_directory_url(TRY(String::formatted("file://{}/res", s_serenity_resource_root)));
+    Web::set_error_page_url(TRY(String::formatted("file://{}/res/html/error.html", s_serenity_resource_root)));
     Web::set_directory_page_url(TRY(String::formatted("file://{}/res/html/directory.html", s_serenity_resource_root)));
 
     TRY(Web::Bindings::initialize_main_thread_vm());

Ladybird/WebContent/main.cpp

@@ -97,6 +97,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     Web::Platform::FontPlugin::install(*new Ladybird::FontPlugin(is_layout_test_mode));
 
     Web::set_resource_directory_url(TRY(String::formatted("file://{}/res", s_serenity_resource_root)));
+    Web::set_error_page_url(TRY(String::formatted("file://{}/res/html/error.html", s_serenity_resource_root)));
     Web::set_directory_page_url(TRY(String::formatted("file://{}/res/html/directory.html", s_serenity_resource_root)));
 
     TRY(Web::Bindings::initialize_main_thread_vm());

Userland/Libraries/LibWeb/DOM/DocumentLoading.cpp

@@ -344,7 +344,8 @@ JS::GCPtr<DOM::Document> create_document_for_inline_content(JS::GCPtr<HTML::Navi
     // 6. Either associate document with a custom rendering that is not rendered using the normal Document rendering rules, or mutate document until it represents the content the
     //    user agent wants to render.
     auto parser = HTML::HTMLParser::create(document, content_html, "utf-8");
-    parser->run(AK::URL("about:error"));
+    document->set_url(AK::URL("about:error"));
+    parser->run();
 
     // 7. Return document.
     return document;

Userland/Libraries/LibWeb/HTML/Navigable.cpp

@@ -27,6 +27,7 @@
 #include <LibWeb/HTML/TraversableNavigable.h>
 #include <LibWeb/Infra/Strings.h>
 #include <LibWeb/Layout/Node.h>
+#include <LibWeb/Loader/GeneratedPagesLoader.h>
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/Platform/EventLoopPlugin.h>
 #include <LibWeb/XHR/FormData.h>
@@ -998,9 +999,8 @@ WebIDL::ExceptionOr<void> Navigable::populate_session_history_entry_document(
         if (failure) {
             // 1. Set entry's document state's document to the result of creating a document for inline content that doesn't have a DOM, given navigable, null, and navTimingType.
             //    The inline content should indicate to the user the sort of error that occurred.
-            // FIXME: Use SourceGenerator to produce error page from file:///res/html/error.html
-            //        and display actual error from fetch response.
-            auto error_html = String::formatted("<h1>Failed to load {}</h1>"sv, entry->url).release_value_but_fixme_should_propagate_errors();
+            // FIXME: Add error message to generated error page
+            auto error_html = load_error_page(entry->url).release_value_but_fixme_should_propagate_errors();
             entry->document_state->set_document(create_document_for_inline_content(this, navigation_id, error_html));
 
             // 2. Set entry's document state's document's salvageable to false.

Userland/Libraries/LibWeb/Loader/GeneratedPagesLoader.cpp

@@ -26,6 +26,18 @@ void set_resource_directory_url(String resource_directory_url)
     s_resource_directory_url = resource_directory_url;
 }
 
+static String s_error_page_url = "file:///res/html/error.html"_string;
+
+String error_page_url()
+{
+    return s_error_page_url;
+}
+
+void set_error_page_url(String error_page_url)
+{
+    s_error_page_url = error_page_url;
+}
+
 static String s_directory_page_url = "file:///res/html/directory.html"_string;
 
 String directory_page_url()
@@ -38,6 +50,20 @@ void set_directory_page_url(String directory_page_url)
     s_directory_page_url = directory_page_url;
 }
 
+ErrorOr<String> load_error_page(AK::URL const& url)
+{
+    // Generate HTML error page from error template file
+    // FIXME: Use an actual templating engine (our own one when it's built, preferably with a way to check these usages at compile time)
+    auto template_path = AK::URL::create_with_url_or_path(error_page_url().to_deprecated_string()).serialize_path();
+    auto template_file = TRY(Core::File::open(template_path, Core::File::OpenMode::Read));
+    auto template_contents = TRY(template_file->read_until_eof());
+    StringBuilder builder;
+    SourceGenerator generator { builder };
+    generator.set("resource_directory_url", resource_directory_url());
+    generator.set("failed_url", url.to_deprecated_string());
+    generator.append(template_contents);
+    return TRY(String::from_utf8(generator.as_string_view()));
+}
 
 ErrorOr<String> load_file_directory_page(LoadRequest const& request)
 {

Userland/Libraries/LibWeb/Loader/GeneratedPagesLoader.h

@@ -6,16 +6,20 @@
 
 #pragma once
 
-#include <LibWeb/Loader/Resource.h>
 #include <LibWeb/Fetch/Infrastructure/HTTP/Responses.h>
+#include <LibWeb/Loader/Resource.h>
 
 namespace Web {
 
 String resource_directory_url();
 void set_resource_directory_url(String);
+String error_page_url();
+void set_error_page_url(String);
 String directory_page_url();
 void set_directory_page_url(String);
 
+ErrorOr<String> load_error_page(AK::URL const&);
+
 ErrorOr<String> load_file_directory_page(LoadRequest const&);
 
 }