Merge branch 'patch/fix-markdown-preview-wikis' into 'master'

Wiki preview URL converting problem [via Markdown]

Current implementation when rendering the preview, thinks relative links are for project repository files.

We are creating a new preview route that will define correct context data to render for wikis instead.

Fixes #2380, #1184

See merge request !3461

3 files changed, 70 insertions, 6 deletions

diff --git a/lib/banzai/filter/gollum_tags_filter.rb b/lib/banzai/filter/gollum_tags_filter.rb
index 7ce26db1b90..d08267a9d6c 100644
--- a/lib/banzai/filter/gollum_tags_filter.rb
+++ b/lib/banzai/filter/gollum_tags_filter.rb
@@ -118,7 +118,7 @@ module Banzai
         end
 
         if path
-          content_tag(:img, nil, src: path)
+          content_tag(:img, nil, src: path, class: 'gfm')
         end
       end
 
@@ -144,12 +144,18 @@ module Banzai
       # if it is not.
       def process_page_link_tag(parts)
         if parts.size == 1
-          url = parts[0].strip
+          reference = parts[0].strip
         else
-          name, url = *parts.compact.map(&:strip)
+          name, reference = *parts.compact.map(&:strip)
         end
 
-        content_tag(:a, name || url, href: url)
+        if url?(reference)
+          href = reference
+        else
+          href = ::File.join(project_wiki_base_path, reference)
+        end
+
+        content_tag(:a, name || reference, href: href, class: 'gfm')
       end
 
       def project_wiki
diff --git a/lib/banzai/filter/wiki_link_filter.rb b/lib/banzai/filter/wiki_link_filter.rb
new file mode 100644
index 00000000000..06d10c98501
--- /dev/null
+++ b/lib/banzai/filter/wiki_link_filter.rb
@@ -0,0 +1,56 @@
+require 'uri'
+
+module Banzai
+  module Filter
+    # HTML filter that "fixes" relative links to files in a repository.
+    #
+    # Context options:
+    #   :project_wiki
+    class WikiLinkFilter < HTML::Pipeline::Filter
+
+      def call
+        return doc unless project_wiki?
+
+        doc.search('a:not(.gfm)').each do |el|
+          process_link_attr el.attribute('href')
+        end
+
+        doc
+      end
+
+      protected
+
+      def project_wiki?
+        !context[:project_wiki].nil?
+      end
+
+      def process_link_attr(html_attr)
+        return if html_attr.blank? || file_reference?(html_attr)
+
+        uri = URI(html_attr.value)
+        if uri.relative? && uri.path.present?
+          html_attr.value = rebuild_wiki_uri(uri).to_s
+        end
+      rescue URI::Error
+        # noop
+      end
+
+      def rebuild_wiki_uri(uri)
+        uri.path = ::File.join(project_wiki_base_path, uri.path)
+        uri
+      end
+
+      def file_reference?(html_attr)
+        !File.extname(html_attr.value).blank?
+      end
+
+      def project_wiki
+        context[:project_wiki]
+      end
+
+      def project_wiki_base_path
+        project_wiki && project_wiki.wiki_base_path
+      end
+    end
+  end
+end
diff --git a/lib/banzai/pipeline/wiki_pipeline.rb b/lib/banzai/pipeline/wiki_pipeline.rb
index 0b5a9e0b2b8..c37b8e71cb0 100644
--- a/lib/banzai/pipeline/wiki_pipeline.rb
+++ b/lib/banzai/pipeline/wiki_pipeline.rb
@@ -2,8 +2,10 @@ module Banzai
   module Pipeline
     class WikiPipeline < FullPipeline
       def self.filters
-        @filters ||= super.insert_after(Filter::TableOfContentsFilter,
-                                        Filter::GollumTagsFilter)
+        @filters ||= begin
+          super.insert_after(Filter::TableOfContentsFilter, Filter::GollumTagsFilter)
+               .insert_before(Filter::TaskListFilter, Filter::WikiLinkFilter)
+        end
       end
     end
   end