Introduce group basic federation, event new page and notifications

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

lib/service/rich_media/parsers/fallback.ex

@@ -0,0 +1,41 @@
+# Portions of this file are derived from Pleroma:
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Mobilizon.Service.RichMedia.Parsers.Fallback do
+  @moduledoc """
+  Module to parse fallback data in HTML pages (plain old title and meta description)
+  """
+  @spec parse(String.t(), map()) :: {:ok, map()} | {:error, String.t()}
+  def parse(html, data) do
+    data =
+      data
+      |> maybe_put(html, :title)
+      |> maybe_put(html, :description)
+
+    if Enum.empty?(data) do
+      {:error, "Not even a title"}
+    else
+      {:ok, data}
+    end
+  end
+
+  defp maybe_put(meta, html, attr) do
+    case get_page(html, attr) do
+      "" -> meta
+      content -> Map.put_new(meta, attr, content)
+    end
+  end
+
+  defp get_page(html, :title) do
+    html |> Floki.find("html head title") |> List.first() |> Floki.text() |> String.trim()
+  end
+
+  defp get_page(html, :description) do
+    case html |> Floki.find("html head meta[name='description']") |> List.first() do
+      nil -> ""
+      elem -> elem |> Floki.attribute("content") |> List.first() |> String.trim()
+    end
+  end
+end