From b0394fdb02b49076bc4b8023f8c480f886d80231 Mon Sep 17 00:00:00 2001
From: Thomas Citharel <tcit@tcit.fr>
Date: Wed, 19 May 2021 11:06:30 +0200
Subject: [PATCH] Use post picture as OGP picture if existing

Signed-off-by: Thomas Citharel <tcit@tcit.fr>
---
 lib/service/metadata/post.ex            | 34 ++++++++++++++++++-------
 test/service/metadata/metadata_test.exs |  2 +-
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/lib/service/metadata/post.ex b/lib/service/metadata/post.ex
index 6553b78f9..db3486eba 100644
--- a/lib/service/metadata/post.ex
+++ b/lib/service/metadata/post.ex
@@ -1,6 +1,7 @@
 defimpl Mobilizon.Service.Metadata, for: Mobilizon.Posts.Post do
   alias Phoenix.HTML
   alias Phoenix.HTML.Tag
+  alias Mobilizon.Medias.{File, Media}
   alias Mobilizon.Posts.Post
   alias Mobilizon.Web.JsonLD.ObjectView
   import Mobilizon.Service.Metadata.Utils, only: [process_description: 2, strip_tags: 1]
@@ -8,15 +9,17 @@ defimpl Mobilizon.Service.Metadata, for: Mobilizon.Posts.Post do
   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: "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)
+      ]
+      |> maybe_add_post_picture(post)
 
     tags ++
       [
@@ -31,4 +34,17 @@ defimpl Mobilizon.Service.Metadata, for: Mobilizon.Posts.Post do
     |> ObjectView.render(%{post: %{post | title: strip_tags(title)}})
     |> Jason.encode!()
   end
+
+  @spec maybe_add_post_picture(list(), Post.t()) :: list()
+  defp maybe_add_post_picture(tags, %Post{picture: %Media{file: %File{url: url}}}),
+    do:
+      tags ++
+        [
+          Tag.tag(:meta,
+            property: "og:image",
+            content: url
+          )
+        ]
+
+  defp maybe_add_post_picture(tags, _), do: tags
 end
diff --git a/test/service/metadata/metadata_test.exs b/test/service/metadata/metadata_test.exs
index a2148258f..0a747eab2 100644
--- a/test/service/metadata/metadata_test.exs
+++ b/test/service/metadata/metadata_test.exs
@@ -120,7 +120,7 @@ defmodule Mobilizon.Service.MetadataTest do
                  Metadata.Utils.process_description(post.body)
                }\" property=\"og:description\"><meta content=\"article\" property=\"og:type\"><meta content=\"summary\" property=\"twitter:card\"><link href=\"#{
                  post.url
-               }\" rel=\"canonical\"><meta content=\"summary_large_image\" property=\"twitter:card\"><script type=\"application/ld+json\">{\"@context\":\"https://schema.org\",\"@type\":\"Article\",\"author\":{\"@type\":\"Organization\",\"name\":\"#{
+               }\" rel=\"canonical\"><meta content=\"#{post.picture.file.url}\" property=\"og:image\"><meta content=\"summary_large_image\" property=\"twitter:card\"><script type=\"application/ld+json\">{\"@context\":\"https://schema.org\",\"@type\":\"Article\",\"author\":{\"@type\":\"Organization\",\"name\":\"#{
                  post.attributed_to.preferred_username
                }\"},\"dateModified\":\"#{DateTime.to_iso8601(post.updated_at)}\",\"datePublished\":\"#{
                  DateTime.to_iso8601(post.publish_at)