Resolve "DashboardController#activity.json is slow due to SQL"

36 files changed, 429 insertions, 225 deletions

diff --git a/app/controllers/concerns/notes_actions.rb b/app/controllers/concerns/notes_actions.rb
index 57b45f335fa..3c64fd964ff 100644
--- a/app/controllers/concerns/notes_actions.rb
+++ b/app/controllers/concerns/notes_actions.rb
@@ -39,7 +39,7 @@ module NotesActions
     @note = Notes::CreateService.new(note_project, current_user, create_params).execute
 
     if @note.is_a?(Note)
-      Banzai::NoteRenderer.render([@note], @project, current_user)
+      Notes::RenderService.new(current_user).execute([@note], @project)
     end
 
     respond_to do |format|
@@ -52,7 +52,7 @@ module NotesActions
     @note = Notes::UpdateService.new(project, current_user, note_params).execute(note)
 
     if @note.is_a?(Note)
-      Banzai::NoteRenderer.render([@note], @project, current_user)
+      Notes::RenderService.new(current_user).execute([@note], @project)
     end
 
     respond_to do |format|
diff --git a/app/controllers/concerns/renders_notes.rb b/app/controllers/concerns/renders_notes.rb
index 4791bc561a4..824ad06465c 100644
--- a/app/controllers/concerns/renders_notes.rb
+++ b/app/controllers/concerns/renders_notes.rb
@@ -3,7 +3,7 @@ module RendersNotes
     preload_noteable_for_regular_notes(notes)
     preload_max_access_for_authors(notes, @project)
     preload_first_time_contribution_for_authors(noteable, notes)
-    Banzai::NoteRenderer.render(notes, @project, current_user)
+    Notes::RenderService.new(current_user).execute(notes, @project)
 
     notes
   end
diff --git a/app/controllers/dashboard/projects_controller.rb b/app/controllers/dashboard/projects_controller.rb
index cd94a36a6e7..d9884a47ec4 100644
--- a/app/controllers/dashboard/projects_controller.rb
+++ b/app/controllers/dashboard/projects_controller.rb
@@ -57,5 +57,7 @@ class Dashboard::ProjectsController < Dashboard::ApplicationController
     @events = EventCollection
       .new(projects, offset: params[:offset].to_i, filter: event_filter)
       .to_a
+
+    Events::RenderService.new(current_user).execute(@events, atom_request: request.format.atom?)
   end
 end
diff --git a/app/controllers/dashboard_controller.rb b/app/controllers/dashboard_controller.rb
index 19a5db6fd17..280ed93faf8 100644
--- a/app/controllers/dashboard_controller.rb
+++ b/app/controllers/dashboard_controller.rb
@@ -32,6 +32,8 @@ class DashboardController < Dashboard::ApplicationController
     @events = EventCollection
       .new(projects, offset: params[:offset].to_i, filter: @event_filter)
       .to_a
+
+    Events::RenderService.new(current_user).execute(@events)
   end
 
   def set_show_full_reference
diff --git a/app/controllers/groups_controller.rb b/app/controllers/groups_controller.rb
index bc3e95f1aed..eb53a522f90 100644
--- a/app/controllers/groups_controller.rb
+++ b/app/controllers/groups_controller.rb
@@ -155,6 +155,8 @@ class GroupsController < Groups::ApplicationController
     @events = EventCollection
       .new(@projects, offset: params[:offset].to_i, filter: event_filter)
       .to_a
+
+    Events::RenderService.new(current_user).execute(@events, atom_request: request.format.atom?)
   end
 
   def user_actions
diff --git a/app/controllers/projects_controller.rb b/app/controllers/projects_controller.rb
index db543d688a0..1688121e27e 100644
--- a/app/controllers/projects_controller.rb
+++ b/app/controllers/projects_controller.rb
@@ -300,6 +300,8 @@ class ProjectsController < Projects::ApplicationController
     @events = EventCollection
       .new(projects, offset: params[:offset].to_i, filter: event_filter)
       .to_a
+
+    Events::RenderService.new(current_user).execute(@events, atom_request: request.format.atom?)
   end
 
   def project_params
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 4ee855806ab..5fca31b4956 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -108,6 +108,8 @@ class UsersController < ApplicationController
       .references(:project)
       .with_associations
       .limit_recent(20, params[:offset])
+
+    Events::RenderService.new(current_user).execute(@events, atom_request: request.format.atom?)
   end
 
   def load_projects
diff --git a/app/helpers/events_helper.rb b/app/helpers/events_helper.rb
index fd88e0d794a..079b3cd3aa0 100644
--- a/app/helpers/events_helper.rb
+++ b/app/helpers/events_helper.rb
@@ -172,16 +172,6 @@ module EventsHelper
     end
   end
 
-  def event_note(text, options = {})
-    text = first_line_in_markdown(text, 150, options)
-
-    sanitize(
-      text,
-      tags: %w(a img gl-emoji b pre code p span),
-      attributes: Rails::Html::WhiteListSanitizer.allowed_attributes + ['style', 'data-src', 'data-name', 'data-unicode-version']
-    )
-  end
-
   def event_commit_title(message)
     message ||= ''
     (message.split("\n").first || "").truncate(70)
diff --git a/app/helpers/markup_helper.rb b/app/helpers/markup_helper.rb
index 420622399f3..2c85d7d7720 100644
--- a/app/helpers/markup_helper.rb
+++ b/app/helpers/markup_helper.rb
@@ -69,10 +69,16 @@ module MarkupHelper
   # as Markdown.  HTML tags in the parsed output are not counted toward the
   # +max_chars+ limit.  If the length limit falls within a tag's contents, then
   # the tag contents are truncated without removing the closing tag.
-  def first_line_in_markdown(text, max_chars = nil, options = {})
-    md = markdown(text, options).strip
+  def first_line_in_markdown(object, attribute, max_chars = nil, options = {})
+    md = markdown_field(object, attribute, options)
 
-    truncate_visible(md, max_chars || md.length) if md.present?
+    text = truncate_visible(md, max_chars || md.length) if md.present?
+
+    sanitize(
+      text,
+      tags: %w(a img gl-emoji b pre code p span),
+      attributes: Rails::Html::WhiteListSanitizer.allowed_attributes + ['style', 'data-src', 'data-name', 'data-unicode-version']
+    )
   end
 
   def markdown(text, context = {})
@@ -83,15 +89,17 @@ module MarkupHelper
     prepare_for_rendering(html, context)
   end
 
-  def markdown_field(object, field)
+  def markdown_field(object, field, context = {})
     object = object.for_display if object.respond_to?(:for_display)
     redacted_field_html = object.try(:"redacted_#{field}_html")
 
     return '' unless object.present?
     return redacted_field_html if redacted_field_html
 
-    html = Banzai.render_field(object, field)
-    prepare_for_rendering(html, object.banzai_render_context(field))
+    html = Banzai.render_field(object, field, context)
+    context.reverse_merge!(object.banzai_render_context(field)) if object.respond_to?(:banzai_render_context)
+
+    prepare_for_rendering(html, context)
   end
 
   def markup(file_name, text, context = {})
diff --git a/app/services/base_renderer.rb b/app/services/base_renderer.rb
new file mode 100644
index 00000000000..d6e30bd7008
--- /dev/null
+++ b/app/services/base_renderer.rb
@@ -0,0 +1,7 @@
+class BaseRenderer
+  attr_reader :current_user
+
+  def initialize(current_user = nil)
+    @current_user = current_user
+  end
+end
diff --git a/app/services/events/render_service.rb b/app/services/events/render_service.rb
new file mode 100644
index 00000000000..0b62d8aedf1
--- /dev/null
+++ b/app/services/events/render_service.rb
@@ -0,0 +1,21 @@
+module Events
+  class RenderService < BaseRenderer
+    def execute(events, atom_request: false)
+      events.map(&:note).compact.group_by(&:project).each do |project, notes|
+        render_notes(notes, project, atom_request)
+      end
+    end
+
+    private
+
+    def render_notes(notes, project, atom_request)
+      Notes::RenderService.new(current_user).execute(notes, project, render_options(atom_request))
+    end
+
+    def render_options(atom_request)
+      return {} unless atom_request
+
+      { only_path: false, xhtml: true }
+    end
+  end
+end
diff --git a/app/services/notes/render_service.rb b/app/services/notes/render_service.rb
new file mode 100644
index 00000000000..a77e98c2b07
--- /dev/null
+++ b/app/services/notes/render_service.rb
@@ -0,0 +1,21 @@
+module Notes
+  class RenderService < BaseRenderer
+    # Renders a collection of Note instances.
+    #
+    # notes - The notes to render.
+    # project - The project to use for redacting.
+    # user - The user viewing the notes.
+
+    # Possible options:
+    # requested_path - The request path.
+    # project_wiki - The project's wiki.
+    # ref - The current Git reference.
+    # only_path - flag to turn relative paths into absolute ones.
+    # xhtml - flag to save the html in XHTML
+    def execute(notes, project, **opts)
+      renderer = Banzai::ObjectRenderer.new(project, current_user, **opts)
+
+      renderer.render(notes, :note)
+    end
+  end
+end
diff --git a/app/views/dashboard/todos/_todo.html.haml b/app/views/dashboard/todos/_todo.html.haml
index 38fd053ae65..efe1fb99efc 100644
--- a/app/views/dashboard/todos/_todo.html.haml
+++ b/app/views/dashboard/todos/_todo.html.haml
@@ -36,7 +36,7 @@
     .todo-body
       .todo-note
         .md
-          = event_note(todo.body, project: todo.project)
+          = first_line_in_markdown(todo, :body, 150, project: todo.project)
 
   - if todo.pending?
     .todo-actions
diff --git a/app/views/events/_event_note.atom.haml b/app/views/events/_event_note.atom.haml
index 6fa2f9bd4db..7e264eb5575 100644
--- a/app/views/events/_event_note.atom.haml
+++ b/app/views/events/_event_note.atom.haml
@@ -1,2 +1,2 @@
 %div{ xmlns: "http://www.w3.org/1999/xhtml" }
-  = markdown(note.note, pipeline: :atom, project: note.project, author: note.author)
+  = markdown_field(note, :note)
diff --git a/app/views/events/event/_note.html.haml b/app/views/events/event/_note.html.haml
index df4b9562215..de6383e4097 100644
--- a/app/views/events/event/_note.html.haml
+++ b/app/views/events/event/_note.html.haml
@@ -10,7 +10,7 @@
 .event-body
   .event-note
     .md
-      = event_note(event.target.note, project: event.project)
+      = first_line_in_markdown(event.target, :note, 150, project: event.project)
     - note = event.target
     - if note.attachment.url
       - if note.attachment.image?
diff --git a/changelogs/unreleased/27375-dashboard-activity-performance.yml b/changelogs/unreleased/27375-dashboard-activity-performance.yml
new file mode 100644
index 00000000000..87c6197a24d
--- /dev/null
+++ b/changelogs/unreleased/27375-dashboard-activity-performance.yml
@@ -0,0 +1,5 @@
+---
+title: Improve DashboardController#activity.json performance
+merge_request: 14985
+author:
+type: performance
diff --git a/config/initializers/8_metrics.rb b/config/initializers/8_metrics.rb
index 2d8704622b6..dc242c747b9 100644
--- a/config/initializers/8_metrics.rb
+++ b/config/initializers/8_metrics.rb
@@ -77,7 +77,6 @@ def instrument_classes(instrumentation)
 
   instrumentation.instrument_instance_methods(Banzai::ObjectRenderer)
   instrumentation.instrument_instance_methods(Banzai::Redactor)
-  instrumentation.instrument_methods(Banzai::NoteRenderer)
 
   [Issuable, Mentionable, Participable].each do |klass|
     instrumentation.instrument_instance_methods(klass)
diff --git a/lib/banzai.rb b/lib/banzai.rb
index 35ca234c1ba..5df98f66f3b 100644
--- a/lib/banzai.rb
+++ b/lib/banzai.rb
@@ -3,8 +3,8 @@ module Banzai
     Renderer.render(text, context)
   end
 
-  def self.render_field(object, field)
-    Renderer.render_field(object, field)
+  def self.render_field(object, field, context = {})
+    Renderer.render_field(object, field, context)
   end
 
   def self.cache_collection_render(texts_and_contexts)
diff --git a/lib/banzai/filter/absolute_link_filter.rb b/lib/banzai/filter/absolute_link_filter.rb
new file mode 100644
index 00000000000..1ec6201523f
--- /dev/null
+++ b/lib/banzai/filter/absolute_link_filter.rb
@@ -0,0 +1,34 @@
+require 'uri'
+
+module Banzai
+  module Filter
+    # HTML filter that converts relative urls into absolute ones.
+    class AbsoluteLinkFilter < HTML::Pipeline::Filter
+      def call
+        return doc unless context[:only_path] == false
+
+        doc.search('a.gfm').each do |el|
+          process_link_attr el.attribute('href')
+        end
+
+        doc
+      end
+
+      protected
+
+      def process_link_attr(html_attr)
+        return if html_attr.blank?
+        return if html_attr.value.start_with?('//')
+
+        uri = URI(html_attr.value)
+        html_attr.value = absolute_link_attr(uri) if uri.relative?
+      rescue URI::Error
+        # noop
+      end
+
+      def absolute_link_attr(uri)
+        URI.join(Gitlab.config.gitlab.url, uri).to_s
+      end
+    end
+  end
+end
diff --git a/lib/banzai/filter/abstract_reference_filter.rb b/lib/banzai/filter/abstract_reference_filter.rb
index a0f7e4e5ad5..9fef386de16 100644
--- a/lib/banzai/filter/abstract_reference_filter.rb
+++ b/lib/banzai/filter/abstract_reference_filter.rb
@@ -311,30 +311,6 @@ module Banzai
       def project_refs_cache
         RequestStore[:banzai_project_refs] ||= {}
       end
-
-      def cached_call(request_store_key, cache_key, path: [])
-        if RequestStore.active?
-          cache = RequestStore[request_store_key] ||= Hash.new do |hash, key|
-            hash[key] = Hash.new { |h, k| h[k] = {} }
-          end
-
-          cache = cache.dig(*path) if path.any?
-
-          get_or_set_cache(cache, cache_key) { yield }
-        else
-          yield
-        end
-      end
-
-      def get_or_set_cache(cache, key)
-        if cache.key?(key)
-          cache[key]
-        else
-          value = yield
-          cache[key] = value if key.present?
-          value
-        end
-      end
     end
   end
 end
diff --git a/lib/banzai/filter/reference_filter.rb b/lib/banzai/filter/reference_filter.rb
index c6ae28adf87..b9d5ecf70ec 100644
--- a/lib/banzai/filter/reference_filter.rb
+++ b/lib/banzai/filter/reference_filter.rb
@@ -8,6 +8,8 @@ module Banzai
     #   :project (required) - Current project, ignored if reference is cross-project.
     #   :only_path          - Generate path-only links.
     class ReferenceFilter < HTML::Pipeline::Filter
+      include RequestStoreReferenceCache
+
       class << self
         attr_accessor :reference_type
       end
diff --git a/lib/banzai/filter/user_reference_filter.rb b/lib/banzai/filter/user_reference_filter.rb
index afb6e25963c..c7fa8a8119f 100644
--- a/lib/banzai/filter/user_reference_filter.rb
+++ b/lib/banzai/filter/user_reference_filter.rb
@@ -60,10 +60,14 @@ module Banzai
         self.class.references_in(text) do |match, username|
           if username == 'all' && !skip_project_check?
             link_to_all(link_content: link_content)
-          elsif namespace = namespaces[username.downcase]
-            link_to_namespace(namespace, link_content: link_content) || match
           else
-            match
+            cached_call(:banzai_url_for_object, match, path: [User, username.downcase]) do
+              if namespace = namespaces[username.downcase]
+                link_to_namespace(namespace, link_content: link_content) || match
+              else
+                match
+              end
+            end
           end
         end
       end
@@ -74,7 +78,10 @@ module Banzai
       # The keys of this Hash are the namespace paths, the values the
       # corresponding Namespace objects.
       def namespaces
-        @namespaces ||= Namespace.where_full_path_in(usernames).index_by(&:full_path).transform_keys(&:downcase)
+        @namespaces ||= Namespace.eager_load(:owner, :route)
+                                 .where_full_path_in(usernames)
+                                 .index_by(&:full_path)
+                                 .transform_keys(&:downcase)
       end
 
       # Returns all usernames referenced in the current document.
diff --git a/lib/banzai/note_renderer.rb b/lib/banzai/note_renderer.rb
deleted file mode 100644
index 2b7c10f1a0e..00000000000
--- a/lib/banzai/note_renderer.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-module Banzai
-  module NoteRenderer
-    # Renders a collection of Note instances.
-    #
-    # notes - The notes to render.
-    # project - The project to use for redacting.
-    # user - The user viewing the notes.
-    # path - The request path.
-    # wiki - The project's wiki.
-    # git_ref - The current Git reference.
-    def self.render(notes, project, user = nil, path = nil, wiki = nil, git_ref = nil)
-      renderer = ObjectRenderer.new(project,
-                                    user,
-                                    requested_path: path,
-                                    project_wiki: wiki,
-                                    ref: git_ref)
-
-      renderer.render(notes, :note)
-    end
-  end
-end
diff --git a/lib/banzai/object_renderer.rb b/lib/banzai/object_renderer.rb
index e40556e869c..9bb8ed913d8 100644
--- a/lib/banzai/object_renderer.rb
+++ b/lib/banzai/object_renderer.rb
@@ -37,7 +37,7 @@ module Banzai
 
       objects.each_with_index do |object, index|
         redacted_data = redacted[index]
-        object.__send__("redacted_#{attribute}_html=", redacted_data[:document].to_html.html_safe) # rubocop:disable GitlabSecurity/PublicSend
+        object.__send__("redacted_#{attribute}_html=", redacted_data[:document].to_html(save_options).html_safe) # rubocop:disable GitlabSecurity/PublicSend
         object.user_visible_reference_count = redacted_data[:visible_reference_count] if object.respond_to?(:user_visible_reference_count)
       end
     end
@@ -83,5 +83,10 @@ module Banzai
         skip_redaction: true
       )
     end
+
+    def save_options
+      return {} unless base_context[:xhtml]
+      { save_with: Nokogiri::XML::Node::SaveOptions::AS_XHTML }
+    end
   end
 end
diff --git a/lib/banzai/pipeline/post_process_pipeline.rb b/lib/banzai/pipeline/post_process_pipeline.rb
index 131ac3b0eec..dcd52bc03c7 100644
--- a/lib/banzai/pipeline/post_process_pipeline.rb
+++ b/lib/banzai/pipeline/post_process_pipeline.rb
@@ -3,9 +3,10 @@ module Banzai
     class PostProcessPipeline < BasePipeline
       def self.filters
         FilterArray[
+          Filter::RedactorFilter,
           Filter::RelativeLinkFilter,
           Filter::IssuableStateFilter,
-          Filter::RedactorFilter
+          Filter::AbsoluteLinkFilter
         ]
       end
 
diff --git a/lib/banzai/renderer.rb b/lib/banzai/renderer.rb
index 5f91884a878..5cb9adf52b0 100644
--- a/lib/banzai/renderer.rb
+++ b/lib/banzai/renderer.rb
@@ -32,12 +32,9 @@ module Banzai
     # Convert a Markdown-containing field on an object into an HTML-safe String
     # of HTML. This method is analogous to calling render(object.field), but it
     # can cache the rendered HTML in the object, rather than Redis.
-    #
-    # The context to use is managed by the object and cannot be changed.
-    # Use #render, passing it the field text, if a custom rendering is needed.
-    def self.render_field(object, field)
+    def self.render_field(object, field, context = {})
       unless object.respond_to?(:cached_markdown_fields)
-        return cacheless_render_field(object, field)
+        return cacheless_render_field(object, field, context)
       end
 
       object.refresh_markdown_cache! unless object.cached_html_up_to_date?(field)
@@ -46,9 +43,9 @@ module Banzai
     end
 
     # Same as +render_field+, but without consulting or updating the cache field
-    def self.cacheless_render_field(object, field, options = {})
+    def self.cacheless_render_field(object, field, context = {})
       text = object.__send__(field) # rubocop:disable GitlabSecurity/PublicSend
-      context = object.banzai_render_context(field).merge(options)
+      context = context.reverse_merge(object.banzai_render_context(field)) if object.respond_to?(:banzai_render_context)
 
       cacheless_render(text, context)
     end
diff --git a/lib/banzai/request_store_reference_cache.rb b/lib/banzai/request_store_reference_cache.rb
new file mode 100644
index 00000000000..426131442a2
--- /dev/null
+++ b/lib/banzai/request_store_reference_cache.rb
@@ -0,0 +1,27 @@
+module Banzai
+  module RequestStoreReferenceCache
+    def cached_call(request_store_key, cache_key, path: [])
+      if RequestStore.active?
+        cache = RequestStore[request_store_key] ||= Hash.new do |hash, key|
+          hash[key] = Hash.new { |h, k| h[k] = {} }
+        end
+
+        cache = cache.dig(*path) if path.any?
+
+        get_or_set_cache(cache, cache_key) { yield }
+      else
+        yield
+      end
+    end
+
+    def get_or_set_cache(cache, key)
+      if cache.key?(key)
+        cache[key]
+      else
+        value = yield
+        cache[key] = value if key.present?
+        value
+      end
+    end
+  end
+end
diff --git a/spec/helpers/events_helper_spec.rb b/spec/helpers/events_helper_spec.rb
index d5536fcb22b..8a80b88da5d 100644
--- a/spec/helpers/events_helper_spec.rb
+++ b/spec/helpers/events_helper_spec.rb
@@ -1,96 +1,6 @@
 require 'spec_helper'
 
 describe EventsHelper do
-  describe '#event_note' do
-    let(:user) { build(:user) }
-
-    before do
-      allow(helper).to receive(:current_user).and_return(user)
-    end
-
-    it 'displays one line of plain text without alteration' do
-      input = 'A short, plain note'
-      expect(helper.event_note(input)).to match(input)
-      expect(helper.event_note(input)).not_to match(/\.\.\.\z/)
-    end
-
-    it 'displays inline code' do
-      input = 'A note with `inline code`'
-      expected = 'A note with <code>inline code</code>'
-
-      expect(helper.event_note(input)).to match(expected)
-    end
-
-    it 'truncates a note with multiple paragraphs' do
-      input = "Paragraph 1\n\nParagraph 2"
-      expected = 'Paragraph 1...'
-
-      expect(helper.event_note(input)).to match(expected)
-    end
-
-    it 'displays the first line of a code block' do
-      input = "```\nCode block\nwith two lines\n```"
-      expected = %r{<pre.+><code><span class="line">Code block\.\.\.</span>\n</code></pre>}
-
-      expect(helper.event_note(input)).to match(expected)
-    end
-
-    it 'truncates a single long line of text' do
-      text = 'The quick brown fox jumped over the lazy dog twice' # 50 chars
-      input = text * 4
-      expected = (text * 2).sub(/.{3}/, '...')
-
-      expect(helper.event_note(input)).to match(expected)
-    end
-
-    it 'preserves a link href when link text is truncated' do
-      text = 'The quick brown fox jumped over the lazy dog' # 44 chars
-      input = "#{text}#{text}#{text} " # 133 chars
-      link_url = 'http://example.com/foo/bar/baz' # 30 chars
-      input << link_url
-      expected_link_text = 'http://example...</a>'
-
-      expect(helper.event_note(input)).to match(link_url)
-      expect(helper.event_note(input)).to match(expected_link_text)
-    end
-
-    it 'preserves code color scheme' do
-      input = "```ruby\ndef test\n  'hello world'\nend\n```"
-      expected = "\n<pre class=\"code highlight js-syntax-highlight ruby\">" \
-        "<code><span class=\"line\"><span class=\"k\">def</span> <span class=\"nf\">test</span>...</span>\n" \
-        "</code></pre>"
-      expect(helper.event_note(input)).to eq(expected)
-    end
-
-    it 'preserves data-src for lazy images' do
-      input = "![ImageTest](/uploads/test.png)"
-      image_url = "data-src=\"/uploads/test.png\""
-      expect(helper.event_note(input)).to match(image_url)
-    end
-
-    context 'labels formatting' do
-      let(:input) { 'this should be ~label_1' }
-
-      def format_event_note(project)
-        create(:label, title: 'label_1', project: project)
-
-        helper.event_note(input, { project: project })
-      end
-
-      it 'preserves style attribute for a label that can be accessed by current_user' do
-        project = create(:project, :public)
-
-        expect(format_event_note(project)).to match(/span class=.*style=.*/)
-      end
-
-      it 'does not style a label that can not be accessed by current_user' do
-        project = create(:project, :private)
-
-        expect(format_event_note(project)).to eq("<p>#{input}</p>")
-      end
-    end
-  end
-
   describe '#event_commit_title' do
     let(:message) { "foo & bar " + "A" * 70 + "\n" + "B" * 80 }
     subject { helper.event_commit_title(message) }
diff --git a/spec/helpers/markup_helper_spec.rb b/spec/helpers/markup_helper_spec.rb
index 03d706062b7..62ea6d48542 100644
--- a/spec/helpers/markup_helper_spec.rb
+++ b/spec/helpers/markup_helper_spec.rb
@@ -67,7 +67,7 @@ describe MarkupHelper do
 
     describe 'without redacted attribute' do
       it 'renders the markdown value' do
-        expect(Banzai).to receive(:render_field).with(commit, attribute).and_call_original
+        expect(Banzai).to receive(:render_field).with(commit, attribute, {}).and_call_original
 
         helper.markdown_field(commit, attribute)
       end
@@ -252,38 +252,141 @@ describe MarkupHelper do
   end
 
   describe '#first_line_in_markdown' do
-    it 'truncates Markdown properly' do
-      text = "@#{user.username}, can you look at this?\nHello world\n"
-      actual = first_line_in_markdown(text, 100, project: project)
+    shared_examples_for 'common markdown examples' do
+      let(:project_base) { build(:project, :repository) }
 
-      doc = Nokogiri::HTML.parse(actual)
+      it 'displays inline code' do
+        object = create_object('Text with `inline code`')
+        expected = 'Text with <code>inline code</code>'
 
-      # Make sure we didn't create invalid markup
-      expect(doc.errors).to be_empty
+        expect(first_line_in_markdown(object, attribute, 100, project: project)).to match(expected)
+      end
 
-      # Leading user link
-      expect(doc.css('a').length).to eq(1)
-      expect(doc.css('a')[0].attr('href')).to eq user_path(user)
-      expect(doc.css('a')[0].text).to eq "@#{user.username}"
+      it 'truncates the text with multiple paragraphs' do
+        object = create_object("Paragraph 1\n\nParagraph 2")
+        expected = 'Paragraph 1...'
 
-      expect(doc.content).to eq "@#{user.username}, can you look at this?..."
-    end
+        expect(first_line_in_markdown(object, attribute, 100, project: project)).to match(expected)
+      end
 
-    it 'truncates Markdown with emoji properly' do
-      text = "foo :wink:\nbar :grinning:"
-      actual = first_line_in_markdown(text, 100, project: project)
+      it 'displays the first line of a code block' do
+        object = create_object("```\nCode block\nwith two lines\n```")
+        expected = %r{<pre.+><code><span class="line">Code block\.\.\.</span>\n</code></pre>}
 
-      doc = Nokogiri::HTML.parse(actual)
+        expect(first_line_in_markdown(object, attribute, 100, project: project)).to match(expected)
+      end
 
-      # Make sure we didn't create invalid markup
-      # But also account for the 2 errors caused by the unknown `gl-emoji` elements
-      expect(doc.errors.length).to eq(2)
+      it 'truncates a single long line of text' do
+        text = 'The quick brown fox jumped over the lazy dog twice' # 50 chars
+        object = create_object(text * 4)
+        expected = (text * 2).sub(/.{3}/, '...')
+
+        expect(first_line_in_markdown(object, attribute, 150, project: project)).to match(expected)
+      end
+
+      it 'preserves a link href when link text is truncated' do
+        text = 'The quick brown fox jumped over the lazy dog' # 44 chars
+        input = "#{text}#{text}#{text} " # 133 chars
+        link_url = 'http://example.com/foo/bar/baz' # 30 chars
+        input << link_url
+        object = create_object(input)
+        expected_link_text = 'http://example...</a>'
+
+        expect(first_line_in_markdown(object, attribute, 150, project: project)).to match(link_url)
+        expect(first_line_in_markdown(object, attribute, 150, project: project)).to match(expected_link_text)
+      end
+
+      it 'preserves code color scheme' do
+        object = create_object("```ruby\ndef test\n  'hello world'\nend\n```")
+        expected = "\n<pre class=\"code highlight js-syntax-highlight ruby\">" \
+          "<code><span class=\"line\"><span class=\"k\">def</span> <span class=\"nf\">test</span>...</span>\n" \
+          "</code></pre>"
+
+        expect(first_line_in_markdown(object, attribute, 150, project: project)).to eq(expected)
+      end
+
+      it 'preserves data-src for lazy images' do
+        object = create_object("![ImageTest](/uploads/test.png)")
+        image_url = "data-src=\".*/uploads/test.png\""
+
+        expect(first_line_in_markdown(object, attribute, 150, project: project)).to match(image_url)
+      end
+
+      context 'labels formatting' do
+        let(:label_title) { 'this should be ~label_1' }
+
+        def create_and_format_label(project)
+          create(:label, title: 'label_1', project: project)
+          object = create_object(label_title, project: project)
 
-      expect(doc.css('gl-emoji').length).to eq(2)
-      expect(doc.css('gl-emoji')[0].attr('data-name')).to eq 'wink'
-      expect(doc.css('gl-emoji')[1].attr('data-name')).to eq 'grinning'
+          first_line_in_markdown(object, attribute, 150, project: project)
+        end
 
-      expect(doc.content).to eq "foo 😉\nbar 😀"
+        it 'preserves style attribute for a label that can be accessed by current_user' do
+          project = create(:project, :public)
+
+          expect(create_and_format_label(project)).to match(/span class=.*style=.*/)
+        end
+
+        it 'does not style a label that can not be accessed by current_user' do
+          project = create(:project, :private)
+
+          expect(create_and_format_label(project)).to eq("<p>#{label_title}</p>")
+        end
+      end
+
+      it 'truncates Markdown properly' do
+        object = create_object("@#{user.username}, can you look at this?\nHello world\n")
+        actual = first_line_in_markdown(object, attribute, 100, project: project)
+
+        doc = Nokogiri::HTML.parse(actual)
+
+        # Make sure we didn't create invalid markup
+        expect(doc.errors).to be_empty
+
+        # Leading user link
+        expect(doc.css('a').length).to eq(1)
+        expect(doc.css('a')[0].attr('href')).to eq user_path(user)
+        expect(doc.css('a')[0].text).to eq "@#{user.username}"
+
+        expect(doc.content).to eq "@#{user.username}, can you look at this?..."
+      end
+
+      it 'truncates Markdown with emoji properly' do
+        object = create_object("foo :wink:\nbar :grinning:")
+        actual = first_line_in_markdown(object, attribute, 100, project: project)
+
+        doc = Nokogiri::HTML.parse(actual)
+
+        # Make sure we didn't create invalid markup
+        # But also account for the 2 errors caused by the unknown `gl-emoji` elements
+        expect(doc.errors.length).to eq(2)
+
+        expect(doc.css('gl-emoji').length).to eq(2)
+        expect(doc.css('gl-emoji')[0].attr('data-name')).to eq 'wink'
+        expect(doc.css('gl-emoji')[1].attr('data-name')).to eq 'grinning'
+
+        expect(doc.content).to eq "foo 😉\nbar 😀"
+      end
+    end
+
+    context 'when the asked attribute can be redacted' do
+      include_examples 'common markdown examples' do
+        let(:attribute) { :note }
+        def create_object(title, project: project_base)
+          build(:note, note: title, project: project)
+        end
+      end
+    end
+
+    context 'when the asked attribute can not be redacted' do
+      include_examples 'common markdown examples' do
+        let(:attribute) { :body }
+        def create_object(title, project: project_base)
+          issue = build(:issue, title: title)
+          build(:todo, :done, project: project_base, author: user, target: issue)
+        end
+      end
     end
   end
 
diff --git a/spec/lib/banzai/commit_renderer_spec.rb b/spec/lib/banzai/commit_renderer_spec.rb
index 049d025a5b9..84adaebdcbe 100644
--- a/spec/lib/banzai/commit_renderer_spec.rb
+++ b/spec/lib/banzai/commit_renderer_spec.rb
@@ -10,7 +10,7 @@ describe Banzai::CommitRenderer do
 
       described_class::ATTRIBUTES.each do |attr|
         expect_any_instance_of(Banzai::ObjectRenderer).to receive(:render).with([project.commit], attr).once.and_call_original
-        expect(Banzai::Renderer).to receive(:cacheless_render_field).with(project.commit, attr)
+        expect(Banzai::Renderer).to receive(:cacheless_render_field).with(project.commit, attr, {})
       end
 
       described_class.render([project.commit], project, user)
diff --git a/spec/lib/banzai/filter/absolute_link_filter_spec.rb b/spec/lib/banzai/filter/absolute_link_filter_spec.rb
new file mode 100644
index 00000000000..a3ad056efcd
--- /dev/null
+++ b/spec/lib/banzai/filter/absolute_link_filter_spec.rb
@@ -0,0 +1,58 @@
+require 'spec_helper'
+
+describe Banzai::Filter::AbsoluteLinkFilter do
+  def filter(doc, context = {})
+    described_class.call(doc, context)
+  end
+
+  context 'with html links' do
+    context 'if only_path is false' do
+      let(:only_path_context) do
+        { only_path: false }
+      end
+      let(:fake_url) { 'http://www.example.com' }
+
+      before do
+        allow(Gitlab.config.gitlab).to receive(:url).and_return(fake_url)
+      end
+
+      context 'has the .gfm class' do
+        it 'converts a relative url into absolute' do
+          doc = filter(link('/foo', 'gfm'), only_path_context)
+          expect(doc.at_css('a')['href']).to eq "#{fake_url}/foo"
+        end
+
+        it 'does not change the url if it already absolute' do
+          doc = filter(link("#{fake_url}/foo", 'gfm'), only_path_context)
+          expect(doc.at_css('a')['href']).to eq "#{fake_url}/foo"
+        end
+
+        context 'if relative_url_root is set' do
+          it 'joins the url without without doubling the path' do
+            allow(Gitlab.config.gitlab).to receive(:url).and_return("#{fake_url}/gitlab/")
+            doc = filter(link("/gitlab/foo", 'gfm'), only_path_context)
+            expect(doc.at_css('a')['href']).to eq "#{fake_url}/gitlab/foo"
+          end
+        end
+      end
+
+      context 'has not the .gfm class' do
+        it 'does not convert a relative url into absolute' do
+          doc = filter(link('/foo'), only_path_context)
+          expect(doc.at_css('a')['href']).to eq '/foo'
+        end
+      end
+    end
+
+    context 'if only_path is not false' do
+      it 'does not convert a relative url into absolute' do
+        expect(filter(link('/foo', 'gfm')).at_css('a')['href']).to eq '/foo'
+        expect(filter(link('/foo')).at_css('a')['href']).to eq '/foo'
+      end
+    end
+  end
+
+  def link(path, css_class = '')
+    %(<a class="#{css_class}" href="#{path}">example</a>)
+  end
+end
diff --git a/spec/lib/banzai/note_renderer_spec.rb b/spec/lib/banzai/note_renderer_spec.rb
deleted file mode 100644
index 32764bee5eb..00000000000
--- a/spec/lib/banzai/note_renderer_spec.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-require 'spec_helper'
-
-describe Banzai::NoteRenderer do
-  describe '.render' do
-    it 'renders a Note' do
-      note = double(:note)
-      project = double(:project)
-      wiki = double(:wiki)
-      user = double(:user)
-
-      expect(Banzai::ObjectRenderer).to receive(:new)
-        .with(project, user,
-             requested_path: 'foo',
-             project_wiki: wiki,
-             ref: 'bar')
-        .and_call_original
-
-      expect_any_instance_of(Banzai::ObjectRenderer)
-        .to receive(:render).with([note], :note)
-
-      described_class.render([note], project, user, 'foo', wiki, 'bar')
-    end
-  end
-end
diff --git a/spec/lib/banzai/object_renderer_spec.rb b/spec/lib/banzai/object_renderer_spec.rb
index b172a1b718c..074d521a5c6 100644
--- a/spec/lib/banzai/object_renderer_spec.rb
+++ b/spec/lib/banzai/object_renderer_spec.rb
@@ -22,7 +22,7 @@ describe Banzai::ObjectRenderer do
       end
 
       it 'retrieves field content using Banzai::Renderer.render_field' do
-        expect(Banzai::Renderer).to receive(:render_field).with(object, :note).and_call_original
+        expect(Banzai::Renderer).to receive(:render_field).with(object, :note, {}).and_call_original
 
         renderer.render([object], :note)
       end
@@ -68,7 +68,7 @@ describe Banzai::ObjectRenderer do
       end
 
       it 'retrieves field content using Banzai::Renderer.cacheless_render_field' do
-        expect(Banzai::Renderer).to receive(:cacheless_render_field).with(commit, :title).and_call_original
+        expect(Banzai::Renderer).to receive(:cacheless_render_field).with(commit, :title, {}).and_call_original
 
         renderer.render([commit], :title)
       end
diff --git a/spec/lib/banzai/renderer_spec.rb b/spec/lib/banzai/renderer_spec.rb
index 81a04a2d46d..650cecfc778 100644
--- a/spec/lib/banzai/renderer_spec.rb
+++ b/spec/lib/banzai/renderer_spec.rb
@@ -18,7 +18,7 @@ describe Banzai::Renderer do
       let(:commit) { create(:project, :repository).commit }
 
       it 'returns cacheless render field' do
-        expect(renderer).to receive(:cacheless_render_field).with(commit, :title)
+        expect(renderer).to receive(:cacheless_render_field).with(commit, :title, {})
 
         renderer.render_field(commit, :title)
       end
diff --git a/spec/services/events/render_service_spec.rb b/spec/services/events/render_service_spec.rb
new file mode 100644
index 00000000000..b4a4a44d07b
--- /dev/null
+++ b/spec/services/events/render_service_spec.rb
@@ -0,0 +1,37 @@
+require 'spec_helper'
+
+describe Events::RenderService do
+  describe '#execute' do
+    let!(:note) { build(:note) }
+    let!(:event) { build(:event, target: note, project: note.project) }
+    let!(:user) { build(:user) }
+
+    context 'when the request format is atom' do
+      it 'renders the note inside events' do
+        expect(Banzai::ObjectRenderer).to receive(:new)
+          .with(event.project, user,
+                only_path: false,
+                xhtml: true)
+          .and_call_original
+
+        expect_any_instance_of(Banzai::ObjectRenderer)
+          .to receive(:render).with([note], :note)
+
+        described_class.new(user).execute([event], atom_request: true)
+      end
+    end
+
+    context 'when the request format is not atom' do
+      it 'renders the note inside events' do
+        expect(Banzai::ObjectRenderer).to receive(:new)
+          .with(event.project, user, {})
+          .and_call_original
+
+        expect_any_instance_of(Banzai::ObjectRenderer)
+          .to receive(:render).with([note], :note)
+
+        described_class.new(user).execute([event], atom_request: false)
+      end
+    end
+  end
+end
diff --git a/spec/services/notes/render_service_spec.rb b/spec/services/notes/render_service_spec.rb
new file mode 100644
index 00000000000..faac498037f
--- /dev/null
+++ b/spec/services/notes/render_service_spec.rb
@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+describe Notes::RenderService do
+  describe '#execute' do
+    it 'renders a Note' do
+      note = double(:note)
+      project = double(:project)
+      wiki = double(:wiki)
+      user = double(:user)
+
+      expect(Banzai::ObjectRenderer).to receive(:new)
+        .with(project, user,
+             requested_path: 'foo',
+             project_wiki: wiki,
+             ref: 'bar',
+             only_path: nil,
+             xhtml: false)
+        .and_call_original
+
+      expect_any_instance_of(Banzai::ObjectRenderer)
+        .to receive(:render).with([note], :note)
+
+      described_class.new(user).execute([note], project,
+                                        requested_path: 'foo',
+                                        project_wiki: wiki,
+                                        ref: 'bar',
+                                        only_path: nil,
+                                        xhtml: false)
+    end
+  end
+end