Ticket #6481: 6481.7.diff

src/wp-admin/includes/schema.php

@@ -397 +397 @@
         'links_updated_date_format' => __('F j, Y g:i a'),
         'comment_moderation' => 0,
         'moderation_notify' => 1,
-        'permalink_structure' => '',
+        'permalink_structure' => '/%year%/%monthnum%/%day%/%postname%/',
         'gzipcompression' => 0,
         'hack_file' => 0,
         'blog_charset' => 'UTF-8',
@@ -495 +495 @@
         if ( is_multisite() ) {
                 /* translators: blog tagline */
                 $options[ 'blogdescription' ] = sprintf(__('Just another %s site'), get_current_site()->site_name );
-                $options[ 'permalink_structure' ] = '/%year%/%monthnum%/%day%/%postname%/';
         }
 
         // Set autoload to no for these options

src/wp-admin/includes/upgrade.php

@@ -87 +87 @@
 
         wp_install_defaults($user_id);
 
+        wp_install_verify_pretty_permalinks();
+
         flush_rewrite_rules();
 
         wp_new_blog_notification($blog_title, $guessurl, $user_id, ($email_password ? $user_password : __('The password you chose during the install.') ) );
@@ -260 +262 @@
 }
 endif;
 
+if ( !function_exists('wp_install_verify_pretty_permalinks') ) :
+/**
+ * Verify pretty permalinks.
+ *
+ * This function will verify that pretty permalinks work. 
+ * If pretty permalinks fail to work, the web-server will fall 
+ * back to ugly permalinks by setting an empty permalink structure.
+ *
+ * @since 4.2.0
+ *
+ * @return void
+ */
+function wp_install_verify_pretty_permalinks() {
+        global $wp_rewrite;
+        // Flush rules with the hard option to force refresh of the web-server's
+        // rewrite config file (e.g. .htaccess or web.config).
+        $wp_rewrite->flush_rules( true );
+
+        // Send a HEAD request to a random page on the site,
+        // and check whether the 'x-pingback' header is returned as expected.
+        $response = wp_remote_get( site_url( '/some-random-404-page/' ) );
+        $x_pingback_header = wp_remote_retrieve_header( $response, 'x-pingback' );
+        $pretty_permalinks = $x_pingback_header && $x_pingback_header === get_bloginfo( 'pingback_url' );
+
+        // Set an empty permalink structure to make it ugly again.
+        if ( ! $pretty_permalinks ) {
+                $wp_rewrite->set_permalink_structure('');
+        }
+}
+endif;
+
 if ( !function_exists('wp_new_blog_notification') ) :
 /**
  * {@internal Missing Short Description}}