Remove custom emojis and trailing whitespaces from previews

lib/pleroma/formatter.ex

@@ -43,7 +43,7 @@ defmodule Pleroma.Formatter do
 
   def emojify(text, nil), do: text
 
-  def emojify(text, emoji) do
+  def emojify(text, emoji, strip \\ false) do
     Enum.reduce(emoji, text, fn {emoji, file}, text ->
       emoji = HTML.strip_tags(emoji)
       file = HTML.strip_tags(file)
@@ -51,14 +51,24 @@ defmodule Pleroma.Formatter do
       String.replace(
         text,
         ":#{emoji}:",
-        "<img height='32px' width='32px' alt='#{emoji}' title='#{emoji}' src='#{
-          MediaProxy.url(file)
-        }' />"
+        if not strip do
+          "<img height='32px' width='32px' alt='#{emoji}' title='#{emoji}' src='#{
+            MediaProxy.url(file)
+          }' />"
+        else
+          ""
+        end
       )
       |> HTML.filter_tags()
     end)
   end
 
+  def demojify(text) do
+    emojify(text, Emoji.get_all(), true)
+  end
+
+  def demojify(text, nil), do: text
+
   def get_emoji(text) when is_binary(text) do
     Enum.filter(Emoji.get_all(), fn {emoji, _} -> String.contains?(text, ":#{emoji}:") end)
   end
@@ -185,6 +195,9 @@ defmodule Pleroma.Formatter do
   end
 
   def truncate(text, max_length \\ 200, omission \\ "...") do
+    # Remove trailing whitespace
+    text = Regex.replace(~r/([^ \t\r\n])([ \t]+$)/u, text, "\\g{1}")
+
     if String.length(text) < max_length do
       text
     else