From 14d4e5ea6ae1392a723cf674add02fb36ce3aa67 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Fri, 16 Feb 2018 17:36:20 +0200
Subject: [PATCH] Add protocol to links if its missing. Fixes #69

---
 mautrix_telegram/formatter.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mautrix_telegram/formatter.py b/mautrix_telegram/formatter.py
index 824dc96e..21236b4f 100644
--- a/mautrix_telegram/formatter.py
+++ b/mautrix_telegram/formatter.py
@@ -353,10 +353,11 @@ def _telegram_to_matrix(text, entities):
                 skip_entity = True
         elif entity_type == MessageEntityEmail:
             html.append(f"<a href='mailto:{entity_text}'>{entity_text}</a>")
-        elif entity_type == MessageEntityUrl:
-            html.append(f"<a href='{entity_text}'>{entity_text}</a>")
-        elif entity_type == MessageEntityTextUrl:
-            html.append(f"<a href='{escape(entity.url)}'>{entity_text}</a>")
+        elif entity_type in {MessageEntityTextUrl, MessageEntityUrl}:
+            url = escape(entity.url) if entity_type == MessageEntityTextUrl else entity_text
+            if not url.startswith(("https://", "http://", "ftp://", "magnet://")):
+                url = "http://" + url
+            html.append(f"<a href='{url}'>{entity_text}</a>")
         elif entity_type == MessageEntityBotCommand:
             html.append(f"<font color='blue'>!{entity_text[1:]}")
         elif entity_type == MessageEntityHashtag: