# It is common in any rails application to have some meta tags in your HTML as title, description, keywords , fb meta tags,...

# BAD
# in app/views/layouts/application.html.erb
<meta name="description" content="<%= @description%>" />
<meta property="og:image" content="<%= @image_url %>" />
# in each controller
@description = 
@image_url =

# Better but bad
# in app/views/layouts/application.html.erb
<meta name="description" content="<%= yield(:description) %>" />
<meta property="og:image" content="<%= yield(:image_url) %>" />
# In each view
content_for(:title, @product.title)
content_for(:title, @product.description)

# Best

def og_tags(*tags)
  content = tags.reduce({}) do |result, set|
    result.merge! set
  end

  raw(content.map do |key, value|
    tag :meta, content: value, property: "og:#{key}"
  end.join("\n"))
end

# Then a helper method that pulls standard attrs (name, desc, image, ...) from a piece of content:

def standard_og_stuff(content)
  {:title => content.name,
   :description => content.description
  }
end
Then combine in view:

<%=
  og_tags(standard_og_stuff(@product), {
    :type => 'video.tv_show',
    :other_tag => 'something'
  })
%>