Correctly escape user-defined names in emails

Closes #1151

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

lib/web/views/email_view.ex

@@ -4,12 +4,13 @@ defmodule Mobilizon.Web.EmailView do
     pattern: "**/*",
     namespace: Mobilizon.Web
 
+  alias Mobilizon.Actors.Actor
   alias Mobilizon.Service.Address
   alias Mobilizon.Service.DateTime, as: DateTimeRenderer
   alias Mobilizon.Web.Router.Helpers, as: Routes
   import Mobilizon.Web.Gettext
   import Mobilizon.Service.Metadata.Utils, only: [process_description: 1]
-  import Phoenix.HTML, only: [raw: 1]
+  import Phoenix.HTML, only: [raw: 1, html_escape: 1, safe_to_string: 1]
 
   defdelegate datetime_to_string(datetime, locale \\ "en", format \\ :medium),
     to: DateTimeRenderer
@@ -24,4 +25,20 @@ defmodule Mobilizon.Web.EmailView do
   defdelegate datetime_relative(datetime, locale \\ "en"), to: DateTimeRenderer
   defdelegate render_address(address), to: Address
   defdelegate is_same_day?(one, two), to: DateTimeRenderer
+  defdelegate display_name_and_username(actor), to: Actor
+  defdelegate display_name(actor), to: Actor
+  defdelegate preferred_username_and_domain(actor), to: Actor
+
+  @spec escape_html(String.t()) :: String.t()
+  def escape_html(string) do
+    string
+    |> html_escape()
+    |> safe_to_string()
+  end
+
+  def escaped_display_name_and_username(actor) do
+    actor
+    |> Actor.display_name_and_username()
+    |> escape_html()
+  end
 end