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diff --git a/lib/pleroma/web/metadata/providers/open_graph.ex b/lib/pleroma/web/metadata/providers/open_graph.ex
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+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Metadata.Providers.OpenGraph do
+  alias Pleroma.User
+  alias Pleroma.Web.MediaProxy
+  alias Pleroma.Web.Metadata
+  alias Pleroma.Web.Metadata.Providers.Provider
+  alias Pleroma.Web.Metadata.Utils
+
+  @behaviour Provider
+  @media_types ["image", "audio", "video"]
+
+  @impl Provider
+  def build_tags(%{
+        object: object,
+        url: url,
+        user: user
+      }) do
+    attachments = build_attachments(object)
+    scrubbed_content = Utils.scrub_html_and_truncate(object)
+
+    [
+      {:meta,
+       [
+         property: "og:title",
+         content: Utils.user_name_string(user)
+       ], []},
+      {:meta, [property: "og:url", content: url], []},
+      {:meta,
+       [
+         property: "og:description",
+         content: scrubbed_content
+       ], []},
+      {:meta, [property: "og:type", content: "article"], []}
+    ] ++
+      if attachments == [] or Metadata.activity_nsfw?(object) do
+        [
+          {:meta, [property: "og:image", content: MediaProxy.preview_url(User.avatar_url(user))],
+           []},
+          {:meta, [property: "og:image:width", content: 150], []},
+          {:meta, [property: "og:image:height", content: 150], []}
+        ]
+      else
+        attachments
+      end
+  end
+
+  @impl Provider
+  def build_tags(%{user: user}) do
+    with truncated_bio = Utils.scrub_html_and_truncate(user.bio) do
+      [
+        {:meta,
+         [
+           property: "og:title",
+           content: Utils.user_name_string(user)
+         ], []},
+        {:meta, [property: "og:url", content: user.uri || user.ap_id], []},
+        {:meta, [property: "og:description", content: truncated_bio], []},
+        {:meta, [property: "og:type", content: "article"], []},
+        {:meta, [property: "og:image", content: MediaProxy.preview_url(User.avatar_url(user))],
+         []},
+        {:meta, [property: "og:image:width", content: 150], []},
+        {:meta, [property: "og:image:height", content: 150], []}
+      ]
+    end
+  end
+
+  defp build_attachments(%{data: %{"attachment" => attachments}}) do
+    Enum.reduce(attachments, [], fn attachment, acc ->
+      rendered_tags =
+        Enum.reduce(attachment["url"], [], fn url, acc ->
+          # TODO: Whatsapp only wants JPEG or PNGs. It seems that if we add a second og:image
+          # object when a Video or GIF is attached it will display that in Whatsapp Rich Preview.
+          case Utils.fetch_media_type(@media_types, url["mediaType"]) do
+            "audio" ->
+              [
+                {:meta, [property: "og:audio", content: MediaProxy.url(url["href"])], []}
+                | acc
+              ]
+
+            # Not using preview_url for this. It saves bandwidth, but the image dimensions will
+            # be wrong. We generate it on the fly and have no way to capture or analyze the
+            # image to get the dimensions. This can be an issue for apps/FEs rendering images
+            # in timelines too, but you can get clever with the aspect ratio metadata as a
+            # workaround.
+            "image" ->
+              [
+                {:meta, [property: "og:image", content: MediaProxy.url(url["href"])], []},
+                {:meta, [property: "og:image:alt", content: attachment["name"]], []}
+                | acc
+              ]
+              |> maybe_add_dimensions(url)
+
+            "video" ->
+              [
+                {:meta, [property: "og:video", content: MediaProxy.url(url["href"])], []}
+                | acc
+              ]
+              |> maybe_add_dimensions(url)
+              |> maybe_add_video_thumbnail(url)
+
+            _ ->
+              acc
+          end
+        end)
+
+      acc ++ rendered_tags
+    end)
+  end
+
+  defp build_attachments(_), do: []
+
+  # We can use url["mediaType"] to dynamically fill the metadata
+  defp maybe_add_dimensions(metadata, url) do
+    type = url["mediaType"] |> String.split("/") |> List.first()
+
+    cond do
+      !is_nil(url["height"]) && !is_nil(url["width"]) ->
+        metadata ++
+          [
+            {:meta, [property: "og:#{type}:width", content: "#{url["width"]}"], []},
+            {:meta, [property: "og:#{type}:height", content: "#{url["height"]}"], []}
+          ]
+
+      true ->
+        metadata
+    end
+  end
+
+  # Media Preview Proxy makes thumbnails of videos without resizing, so we can trust the
+  # width and height of the source video.
+  defp maybe_add_video_thumbnail(metadata, url) do
+    cond do
+      Pleroma.Config.get([:media_preview_proxy, :enabled], false) ->
+        metadata ++
+          [
+            {:meta, [property: "og:image:width", content: "#{url["width"]}"], []},
+            {:meta, [property: "og:image:height", content: "#{url["height"]}"], []},
+            {:meta, [property: "og:image", content: MediaProxy.preview_url(url["href"])], []}
+          ]
+
+      true ->
+        metadata
+    end
+  end
+end