Fix malformed-HTML fallout across RSS, link rewriting, and flash messaging

Editors' TinyMCE output can contain unclosed void elements like <br>,
which is valid HTML5 but invalid XML -- three different places assumed
the stricter rule and broke or silently misbehaved on the looser one.
The Atom feed's <content type="xhtml"> block required real, well-formed
XML structure but was handed a raw, unescaped body string; switched to
type="html" with CGI.escapeHTML, matching how title/summary already
handle the same content. rewrite_links_in_body used libxml's strict XML
parser to rewrite internal links to be locale-prefixed, which raised on
exactly this class of malformed markup -- silently, since the whole
method was wrapped in rescue; nil, meaning the link rewrite (not the
save) quietly failed with no error anywhere. Replaced with Nokogiri's
lenient HTML parser, which repairs malformed void elements rather than
rejecting them; also drops the bare rescue now that the actual failure
mode it was guarding against shouldn't occur, and fixes two adjacent
bugs found while in this method: a typo'd /sytem/uploads/ regex that
could never match, and a missing https:// exclusion alongside the
existing http:// one.

Also addresses stale flash messaging surfaced while testing the above:
update's save confirmation was being clobbered by edit's own "locked
and ready" notice on the very next request, since nothing distinguished
a fresh lock acquisition from a redirect back after saving. The save
confirmation now names the next step (publish from Status) and flags a
stale translation if one exists, using Page#outdated_translations?,
already present but previously unused by any controller.

1 files changed, 12 insertions, 21 deletions

diff --git a/app/models/page.rb b/app/models/page.rb
index fff044e..1a98e08 100644
--- a/app/models/page.rb
+++ b/app/models/page.rb
@@ -243,31 +243,22 @@ class Page < ApplicationRecord
     end
 
     def rewrite_links_in_body
-      begin
-        if self.body
-          tmp_body    = "<div>#{self.body}</div>"
-          xml_string  = XML::Parser.string( tmp_body )
-          xml_doc     = xml_string.parse
-          links       = xml_doc.find("//a[not(starts-with(@href, 'http://'))]")
-          links       = links.reject { |l| l[:href] =~ /system\/uploads/ }
-          locales     = I18n.available_locales.reject {|l| l == :root}
+      return unless self.body
 
-          links.each do |link|
-            unless locales.include? link[:href].slice(1,2).to_sym
-              unless link[:href] =~ /sytem\/uploads/
-                link[:href] = link[:href].sub(/^\//, "/#{I18n.locale}/")
-              end
-            end
-          end
+      doc = Nokogiri::HTML::DocumentFragment.parse(self.body)
+      locales = I18n.available_locales.reject { |l| l == :root }
 
-          tmp_body = xml_doc.to_s.gsub(/(\n\<div\>|\<\/div\>\n)/, "")
-          tmp_body.gsub!("<?xml version=\"1.0\" encoding=\"UTF-8\"?>", "")
+      doc.css('a').each do |link|
+        href = link['href']
+        next unless href
+        next if href.start_with?('http://', 'https://')
+        next if href =~ /system\/uploads/
 
-          self.body = tmp_body
+        unless locales.include?(href.slice(1, 2)&.to_sym)
+          link['href'] = href.sub(/^\//, "/#{I18n.locale}/")
         end
-      rescue
-        nil
       end
-    end
 
+      self.body = doc.to_html
+    end
 end