Introduce group posts

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/service/metadata/comment.ex

@@ -1,6 +1,6 @@
-defimpl Mobilizon.Service.Metadata, for: Mobilizon.Conversations.Comment do
+defimpl Mobilizon.Service.Metadata, for: Mobilizon.Discussions.Comment do
   alias Phoenix.HTML.Tag
-  alias Mobilizon.Conversations.Comment
+  alias Mobilizon.Discussions.Comment
 
   def build_tags(%Comment{} = comment, _locale \\ "en") do
     [

lib/service/metadata/event.ex

@@ -2,10 +2,9 @@ defimpl Mobilizon.Service.Metadata, for: Mobilizon.Events.Event do
   alias Phoenix.HTML
   alias Phoenix.HTML.Tag
   alias Mobilizon.Events.Event
-  alias Mobilizon.Service.Formatter.HTML, as: HTMLFormatter
   alias Mobilizon.Web.JsonLD.ObjectView
   alias Mobilizon.Web.MediaProxy
-  import Mobilizon.Web.Gettext
+  import Mobilizon.Service.Metadata.Utils, only: [process_description: 2, strip_tags: 1]
 
   def build_tags(%Event{} = event, locale \\ "en") do
     event = Map.put(event, :description, process_description(event.description, locale))
@@ -41,24 +40,10 @@ defimpl Mobilizon.Service.Metadata, for: Mobilizon.Events.Event do
       ]
   end
 
-  defp process_description(nil, locale), do: process_description("", locale)
-
-  defp process_description("", locale) do
-    Gettext.put_locale(locale)
-    gettext("The event organizer didn't add any description.")
-  end
-
-  defp process_description(description, _locale) do
-    description
-    |> HTMLFormatter.strip_tags()
-    |> String.slice(0..200)
-    |> (&"#{&1}…").()
-  end
-
   # Insert JSON-LD schema by hand because Tag.content_tag wants to escape it
   defp json(%Event{title: title} = event) do
     "event.json"
-    |> ObjectView.render(%{event: %{event | title: HTMLFormatter.strip_tags(title)}})
+    |> ObjectView.render(%{event: %{event | title: strip_tags(title)}})
     |> Jason.encode!()
   end
 end

lib/service/metadata/post.ex

@@ -0,0 +1,34 @@
+defimpl Mobilizon.Service.Metadata, for: Mobilizon.Posts.Post do
+  alias Phoenix.HTML
+  alias Phoenix.HTML.Tag
+  alias Mobilizon.Posts.Post
+  alias Mobilizon.Web.JsonLD.ObjectView
+  import Mobilizon.Service.Metadata.Utils, only: [process_description: 2, strip_tags: 1]
+
+  def build_tags(%Post{} = post, locale \\ "en") do
+    post = Map.put(post, :body, process_description(post.body, locale))
+
+    tags = [
+      Tag.tag(:meta, property: "og:title", content: post.title),
+      Tag.tag(:meta, property: "og:url", content: post.url),
+      Tag.tag(:meta, property: "og:description", content: post.body),
+      Tag.tag(:meta, property: "og:type", content: "article"),
+      Tag.tag(:meta, property: "twitter:card", content: "summary"),
+      # Tell Search Engines what's the origin
+      Tag.tag(:link, rel: "canonical", href: post.url)
+    ]
+
+    tags ++
+      [
+        Tag.tag(:meta, property: "twitter:card", content: "summary_large_image"),
+        ~s{<script type="application/ld+json">#{json(post)}</script>} |> HTML.raw()
+      ]
+  end
+
+  # Insert JSON-LD schema by hand because Tag.content_tag wants to escape it
+  defp json(%Post{title: title} = post) do
+    "post.json"
+    |> ObjectView.render(%{post: %{post | title: strip_tags(title)}})
+    |> Jason.encode!()
+  end
+end

lib/service/metadata/utils.ex

@@ -3,10 +3,34 @@ defmodule Mobilizon.Service.Metadata.Utils do
   Tools to convert tags to string.
   """
 
+  alias Mobilizon.Service.Formatter.HTML, as: HTMLFormatter
   alias Phoenix.HTML
+  import Mobilizon.Web.Gettext
 
+  @slice_limit 200
+
+  @spec stringify_tags(Enum.t()) :: String.t()
   def stringify_tags(tags), do: Enum.reduce(tags, "", &stringify_tag/2)
 
   defp stringify_tag(tag, acc) when is_tuple(tag), do: acc <> HTML.safe_to_string(tag)
   defp stringify_tag(tag, acc) when is_binary(tag), do: acc <> tag
+
+  @spec strip_tags(String.t()) :: String.t()
+  def strip_tags(text), do: HTMLFormatter.strip_tags(text)
+
+  @spec process_description(String.t(), String.t(), integer()) :: String.t()
+  def process_description(description, locale \\ "en", limit \\ @slice_limit)
+  def process_description(nil, locale, limit), do: process_description("", locale, limit)
+
+  def process_description("", locale, _limit) do
+    Gettext.put_locale(locale)
+    gettext("The event organizer didn't add any description.")
+  end
+
+  def process_description(description, _locale, limit) do
+    description
+    |> HTMLFormatter.strip_tags()
+    |> String.slice(0..limit)
+    |> (&"#{&1}…").()
+  end
 end