Add page descriptions and images

A limited number of pages have defined their own descriptions, but
otherwise we default to the Project's description (if `@project` is
set), or the old `brand_title` fallback.

The image will either be the uploaded project icon (never a generated
one), the user's uploaded icon or Gravatar, or, finally, the GitLab
logo.

6 files changed, 70 insertions, 9 deletions

diff --git a/app/helpers/page_layout_helper.rb b/app/helpers/page_layout_helper.rb
index 9bf750124b2..6b16528dde6 100644
--- a/app/helpers/page_layout_helper.rb
+++ b/app/helpers/page_layout_helper.rb
@@ -8,6 +8,56 @@ module PageLayoutHelper
     @page_title.join(" \u00b7 ")
   end
 
+  # Define or get a description for the current page
+  #
+  # description - String (default: nil)
+  #
+  # If this helper is called multiple times with an argument, only the last
+  # description will be returned when called without an argument. Descriptions
+  # have newlines replaced with spaces and all HTML tags are sanitized.
+  #
+  # Examples:
+  #
+  #   page_description # => "GitLab Community Edition"
+  #   page_description("Foo")
+  #   page_description # => "Foo"
+  #
+  #   page_description("<b>Bar</b>\nBaz")
+  #   page_description # => "Bar Baz"
+  #
+  # Returns an HTML-safe String.
+  def page_description(description = nil)
+    @page_description ||= page_description_default
+
+    if description.present?
+      @page_description = description
+    else
+      sanitize(@page_description.squish, tags: [])
+    end
+  end
+
+  # Default value for page_description when one hasn't been defined manually by
+  # a view
+  def page_description_default
+    if @project
+      @project.description
+    else
+      brand_title
+    end
+  end
+
+  def page_image
+    default = image_url('gitlab_logo.png')
+
+    if @project
+      @project.avatar_url || default
+    elsif @user
+      avatar_icon(@user)
+    else
+      default
+    end
+  end
+
   def header_title(title = nil, title_url = nil)
     if title
       @header_title     = title
diff --git a/app/views/layouts/_head.html.haml b/app/views/layouts/_head.html.haml
index be88ad9e2a6..ad1dacac1c8 100644
--- a/app/views/layouts/_head.html.haml
+++ b/app/views/layouts/_head.html.haml
@@ -1,13 +1,17 @@
 - page_title "GitLab"
+
 %head{prefix: "og: http://ogp.me/ns#"}
   %meta{charset: "utf-8"}
   %meta{'http-equiv' => 'X-UA-Compatible', content: 'IE=edge'}
-  %meta{content: "GitLab Community Edition", name: "description"}
-  %meta{name: 'referrer', content: 'origin-when-cross-origin'}
+
+  %meta{name: "description", content: page_description}
+  %meta{name: 'referrer',    content: 'origin-when-cross-origin'}
 
   -# Open Graph - http://ogp.me/
-  %meta{property: 'og:title', content: page_title}
-  %meta{property: 'og:url',   content: url_for(only_path: false)}
+  %meta{property: 'og:title',       content: page_title}
+  %meta{property: 'og:description', content: page_description}
+  %meta{property: 'og:image',       content: page_image}
+  %meta{property: 'og:url',         content: url_for(only_path: false)}
 
   %title= page_title
 
diff --git a/app/views/projects/issues/show.html.haml b/app/views/projects/issues/show.html.haml
index b6efa05a1ae..f2a261ab426 100644
--- a/app/views/projects/issues/show.html.haml
+++ b/app/views/projects/issues/show.html.haml
@@ -1,4 +1,6 @@
-- page_title "#{@issue.title} (##{@issue.iid})", "Issues"
+- page_title       "#{@issue.title} (##{@issue.iid})", "Issues"
+- page_description @issue.description
+
 = render "header_title"
 
 .issue
diff --git a/app/views/projects/merge_requests/_show.html.haml b/app/views/projects/merge_requests/_show.html.haml
index e9ffbd06be2..75f44557964 100644
--- a/app/views/projects/merge_requests/_show.html.haml
+++ b/app/views/projects/merge_requests/_show.html.haml
@@ -1,4 +1,6 @@
-- page_title "#{@merge_request.title} (##{@merge_request.iid})", "Merge Requests"
+- page_title       "#{@merge_request.title} (##{@merge_request.iid})", "Merge Requests"
+- page_description @merge_request.description
+
 = render "header_title"
 
 - if params[:view] == 'parallel'
diff --git a/app/views/projects/milestones/show.html.haml b/app/views/projects/milestones/show.html.haml
index 7e73ae274e9..1670ea8741a 100644
--- a/app/views/projects/milestones/show.html.haml
+++ b/app/views/projects/milestones/show.html.haml
@@ -1,4 +1,6 @@
-- page_title @milestone.title, "Milestones"
+- page_title       @milestone.title, "Milestones"
+- page_description @milestone.description
+
 = render "header_title"
 
 .detail-page-header
diff --git a/app/views/users/show.html.haml b/app/views/users/show.html.haml
index b7a7eb4e6f7..0bca8177e14 100644
--- a/app/views/users/show.html.haml
+++ b/app/views/users/show.html.haml
@@ -1,5 +1,6 @@
-- page_title    @user.name
-- header_title  @user.name, user_path(@user)
+- page_title       @user.name
+- page_description @user.bio
+- header_title     @user.name, user_path(@user)
 
 = content_for :meta_tags do
   = auto_discovery_link_tag(:atom, user_url(@user, format: :atom), title: "#{@user.name} activity")