From 8bf8e8a46f30de5053b5428c18cccebc8d1c5bbb Mon Sep 17 00:00:00 2001
From: Thomas Citharel <tcit@tcit.fr>
Date: Mon, 4 Mar 2019 18:38:30 +0100
Subject: [PATCH] Add JSON-LD schema

Signed-off-by: Thomas Citharel <tcit@tcit.fr>
---
 .../views/json_ld/object_view.ex              | 57 +++++++++++++++++++
 lib/service/metadata/event.ex                 | 10 ++++
 2 files changed, 67 insertions(+)
 create mode 100644 lib/mobilizon_web/views/json_ld/object_view.ex

diff --git a/lib/mobilizon_web/views/json_ld/object_view.ex b/lib/mobilizon_web/views/json_ld/object_view.ex
new file mode 100644
index 000000000..7d2686056
--- /dev/null
+++ b/lib/mobilizon_web/views/json_ld/object_view.ex
@@ -0,0 +1,57 @@
+defmodule MobilizonWeb.JsonLD.ObjectView do
+  use MobilizonWeb, :view
+
+  alias Mobilizon.Events.{Event, Comment}
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Addresses.Address
+  alias MobilizonWeb.JsonLD.ObjectView
+
+  def render("event.json", %{event: %Event{} = event}) do
+    # TODO: event.description is actually markdown!
+    json_ld = %{
+      "@context" => "https://schema.org",
+      "@type" => "Event",
+      "name" => event.title,
+      "description" => event.description,
+      "image" => [
+        event.thumbnail,
+        event.large_image
+      ],
+      "performer" => %{
+        "@type" =>
+          if(event.organizer_actor.type == :Group, do: "PerformingGroup", else: "Person"),
+        "name" => Actor.display_name(event.organizer_actor)
+      },
+      "location" => render_one(event.physical_address, ObjectView, "place.json", as: :address)
+    }
+
+    json_ld =
+      if event.begins_on,
+        do: Map.put(json_ld, "startDate", DateTime.to_iso8601(event.begins_on)),
+        else: json_ld
+
+    json_ld =
+      if event.ends_on,
+        do: Map.put(json_ld, "endDate", DateTime.to_iso8601(event.ends_on)),
+        else: json_ld
+
+    json_ld
+  end
+
+  def render("place.json", %{address: %Address{} = address}) do
+    %{
+      "@type" => "Place",
+      "name" => address.description,
+      "address" => %{
+        "@type" => "PostalAddress",
+        "streetAddress" => address.streetAddress,
+        "addressLocality" => address.addressLocality,
+        "postalCode" => address.postalCode,
+        "addressRegion" => address.addressRegion,
+        "addressCountry" => address.addressCountry
+      }
+    }
+  end
+
+  def render("place.json", nil), do: %{}
+end
diff --git a/lib/service/metadata/event.ex b/lib/service/metadata/event.ex
index 8a63d7b84..17fdc56ff 100644
--- a/lib/service/metadata/event.ex
+++ b/lib/service/metadata/event.ex
@@ -2,14 +2,17 @@ defimpl Mobilizon.Service.Metadata, for: Mobilizon.Events.Event do
   alias Phoenix.HTML
   alias Phoenix.HTML.Tag
   alias Mobilizon.Events.Event
+  alias MobilizonWeb.JsonLD.ObjectView
 
   def build_tags(%Event{} = event) do
     event
     |> do_build_tags()
     |> Enum.map(&HTML.safe_to_string/1)
     |> Enum.reduce("", fn tag, acc -> acc <> tag end)
+    |> Kernel.<>(build_json_ld_schema(event))
   end
 
+  # Build OpenGraph & Twitter Tags
   defp do_build_tags(%Event{} = event) do
     [
       Tag.tag(:meta, property: "og:title", content: event.title),
@@ -21,4 +24,11 @@ defimpl Mobilizon.Service.Metadata, for: Mobilizon.Events.Event do
       Tag.tag(:meta, property: "twitter:card", content: "summary_large_image")
     ]
   end
+
+  # Insert JSON-LD schema by hand because Tag.content_tag wants to escape it
+  defp build_json_ld_schema(%Event{} = event) do
+    "<script type=\"application\/ld+json\">" <>
+      (ObjectView.render("event.json", %{event: event})
+       |> Jason.encode!()) <> "</script>"
+  end
 end