Fix TypeError when logging into multivisor using authentication

Fixes #72

multivisor/server/util.py

@@ -27,11 +27,11 @@ def constant_time_compare(val1, val2):
 
     Taken from Django Source Code
     """
-    val1 = hashlib.sha1(val1).hexdigest()
+    val1 = hashlib.sha1(_safe_encode(val1)).hexdigest()
     if val2.startswith("{SHA}"):  # password can be specified as SHA-1 hash in config
         val2 = val2.split("{SHA}")[1]
     else:
-        val2 = hashlib.sha1(val2).hexdigest()
+        val2 = hashlib.sha1(_safe_encode(val2)).hexdigest()
     if len(val1) != len(val2):
         return False
     result = 0
@@ -40,6 +40,15 @@ def constant_time_compare(val1, val2):
     return result == 0
 
 
+def _safe_encode(data):
+    """Safely encode @data string to utf-8"""
+    try:
+        result = data.encode("utf-8")
+    except (UnicodeDecodeError, UnicodeEncodeError, AttributeError):
+        result = data
+    return result
+
+
 def login_required(app):
     """
     Decorator to mark view as requiring being logged in