Correctly implement OpenGraph tags

Just defining og:site_name indicates that we support the
OpenGraph protocol, but then we didn't set the required
properties.

app/helpers/open_graph_helper.rb

 module OpenGraphHelper
-  def og_title(post)
-    meta_tag_with_property('og:title', post_page_title(post, :length => 140))
+  def og_title(title)
+    meta_tag_with_property('og:title', title)
   end
 
   def og_type(post)
     meta_tag_with_property('og:type', 'article')
   end
 
-  def og_url(post)
-    meta_tag_with_property('og:url', post_url(post))
+  def og_url(url)
+    meta_tag_with_property('og:url', url)
   end
 
-  def og_image(post)
-    tags = post.photos.map{|x| meta_tag_with_property('og:image', x.url(:thumb_large))}
+  def og_image(post=nil)
+    tags = []
+    tags = post.photos.map{|x| meta_tag_with_property('og:image', x.url(:thumb_large))} if post
     tags << meta_tag_with_property('og:image', default_image_url) if tags.empty?
     tags.join(' ')
   end
 
-  def og_description(post)
-    meta_tag_with_property('og:description', post_page_title(post, :length => 1000))
+  def og_description(description)
+    meta_tag_with_property('og:description', description)
   end
 
-  def og_type
-    meta_tag_with_property('og:type', og_namespace('frame'))
+  def og_type(type='website')
+    meta_tag_with_property('og:type', type)
   end
 
-  def og_namespace(object)
-    namespace = AppConfig.services.facebook.open_graph_namespace.present? ? AppConfig.services.facebook.open_graph_namespace : 'joindiaspora'
-    "#{namespace}:frame"
+  def og_namespace
+    AppConfig.services.facebook.open_graph_namespace
   end
 
-  def og_page_specific_tags(post)
-    [og_title(post), og_type,
-      og_url(post), og_image(post), 
-      og_description(post)].join(' ').html_safe
+  def og_site_name
+    meta_tag_with_property('og:site_name', AppConfig.settings.pod_name)
+  end
+
+  def og_common_tags
+    [og_site_name]
+  end
+
+  def og_general_tags
+    [
+      *og_common_tags,
+      og_type,
+      og_title('diaspora* social network'),
+      og_image,
+      og_url(AppConfig.environment.url),
+      og_description('diaspora* is the online social world where you are in control.')
+    ].join("\n").html_safe
+  end
+
+  def og_page_post_tags(post)
+    [
+      *og_common_tags,
+      og_type("#{og_namespace}:frame"),
+      og_title(post_page_title(post, :length => 140)),
+      og_url(post_url(post)),
+      og_image(post),
+      og_description(post.message.plain_text_without_markdown truncate: 1000)
+    ].join("\n").html_safe
+  end
+
+  def og_prefix
+    "og: http://ogp.me/ns# #{og_namespace}: https://diasporafoundation.org/ns/joindiaspora#"
   end
 
   def meta_tag_with_property(name, content)
-    content_tag(:meta, '', :property => name, :content => content)
+    tag(:meta, :property => name, :content => content)
   end
 
   def og_html(cache)
@@ -53,7 +81,7 @@ module OpenGraphHelper
   def link_to_oembed_image(cache, prefix = 'thumbnail_')
     link_to(oembed_image_tag(cache, prefix), cache.url, :target => '_blank')
   end
-  
+
   def oembed_image_tag(cache, prefix)
     image_tag(cache.data["#{prefix}url"], cache.options_hash(prefix))
   end

app/views/layouts/_open_graph.haml

+- if @post.present?
+  %link{:rel => 'alternate', :type => "application/json+oembed", :href => "#{oembed_url(:url => post_url(@post))}"}
+  = og_page_post_tags(@post)
+- else
+  = og_general_tags

app/views/layouts/application.html.haml

@@ -4,7 +4,7 @@
 
 !!!
 %html{:lang => I18n.locale.to_s, :dir => (rtl?) ? 'rtl' : 'ltr'}
-  %head
+  %head{:prefix => og_prefix}
     %title
       = page_title yield(:page_title)
 
@@ -12,11 +12,12 @@
     %meta{"http-equiv"=>"Content-Type", :content=>"text/html; charset=utf-8"}/
     %meta{:name => "description", :content => "diaspora*"}/
     %meta{:name => "author", :content => "Diaspora, Inc."}/
-    %meta{:property => "og:site_name", :content => "#{AppConfig.settings.pod_name}"}/
 
     %link{:rel => 'shortcut icon', :href => "#{image_path('favicon.png')}" }
     %link{:rel => 'apple-touch-icon', :href => "#{image_path('apple-touch-icon.png')}"}
 
+    = render 'layouts/open_graph'
+
     = chartbeat_head_block
     = include_mixpanel
 
@@ -46,9 +47,6 @@
     = yield(:head)
     = csrf_meta_tag
 
-    - if @post.present?
-      %link{:rel => 'alternate', :type => "application/json+oembed", :href => "#{oembed_url(:url => post_url(@post))}"}
-      = og_page_specific_tags(@post)
 
     = include_gon(:camel_case => true)
 

app/views/layouts/application.mobile.haml

@@ -4,14 +4,13 @@
 
 !!!
 %html{:lang => I18n.locale.to_s, :dir => (rtl?) ? 'rtl' : 'ltr'}
-  %head
+  %head{:prefix => og_prefix}
     %title
       = pod_name
 
     %meta{:name => "description", :content => "diaspora* mobile"}/
     %meta{:name => "author", :content => "Diaspora, Inc."}/
     %meta{:charset => 'utf-8'}/
-    %meta{:property => "og:site_name", :content => "#{AppConfig.settings.pod_name}"}/
 
     / Viewport scale
     %meta{:name =>'viewport', :content => "width=device-width, minimum-scale=1 maximum-scale=1"}/
@@ -30,6 +29,8 @@
     /%meta{:name => "apple-mobile-web-app-capable", :content => "yes"}
     /%link{:rel => "apple-touch-startup-image", :href => "/images/apple-splash.png"}
 
+    = render 'layouts/open_graph'
+
     = chartbeat_head_block
 
     / Stylesheets

config/defaults.yml

@@ -139,6 +139,7 @@ defaults:
       enable: false
       app_id:
       secret:
+      open_graph_namespace: 'joindiaspora'
     twitter:
       enable: false
       key:

lib/rack/chrome_frame.rb

@@ -60,7 +60,7 @@ module Rack
         <meta http-equiv="X-UA-Compatible" content="chrome=1">
       HEAD
 
-      body.gsub!('<head>', "<head>\n" + head )
+      body.gsub!(/<head(.*)>/, "<head\\1>\n" + head )
       body
     end