Add metadata block for social sharing

app/views/landing_page/blocks/_metadata.html.erb

@@ -0,0 +1,21 @@
+<%
+  page_title = @content_item.title
+  page_title = block.data["title"] if block.data["title"]
+
+  page_description = @content_item.description
+  page_description = block.data["description"] if block.data["description"]
+
+  featured_image = image_path(block.data["featured_image"])
+
+  url = "https://www.gov.uk" + @content_item.base_path
+%>
+<% content_for :extra_headers do %>
+  <meta name="description" content="<%= page_description %>" />
+  <meta property="og:title" content="<%= page_title %>">
+  <meta property="og:description" content="<%= page_description %>">
+  <meta property="og:url" content="<%= url %>">
+  <meta property="og:image" content="<%= featured_image %>">
+  <meta property="og:site_name" content="GOV.UK">
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:image:alt" content="<%= block.data["featured_image_alt"] %>">
+<% end %>

lib/data/landing_page_content_items/homepage.yaml

@@ -19,6 +19,12 @@ navigation_groups:
       - text: Be thankful
         href: "/landing-page/be-thankful"
 blocks:
+- type: metadata
+  page_url: "/landing-page/homepage"
+  featured_image: landing_page/placeholder/desktop.png
+  featured_image_alt: a grey placeholder image
+  title: "Add title here to override Whitehall"
+  description: "Add description here to override Whitehall"
 - type: main_navigation
   navigation_group_id: Top Menu
 - type: hero