Add find_charset helper and use where is needed.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/leap/mail/utils.py b/src/leap/mail/utils.py
index 93388d3..6c79227 100644
--- a/src/leap/mail/utils.py
+++ b/src/leap/mail/utils.py
@@ -18,9 +18,14 @@
 Mail utilities.
 """
 import json
+import re
 import traceback
 
 
+CHARSET_PATTERN = r"""charset=([\w-]+)"""
+CHARSET_RE = re.compile(CHARSET_PATTERN, re.IGNORECASE)
+
+
 def first(things):
     """
     Return the head of a collection.
@@ -31,6 +36,26 @@ def first(things):
         return None
 
 
+def find_charset(thing, default=None):
+    """
+    Looks into the object 'thing' for a charset specification.
+    It searchs into the object's `repr`.
+
+    :param thing: the object to look into.
+    :type thing: object
+    :param default: the dafault charset to return if no charset is found.
+    :type default: str
+
+    :returns: the charset or 'default'
+    :rtype: str or None
+    """
+    charset = first(CHARSET_RE.findall(repr(thing)))
+    if charset is None:
+        charset = default
+
+    return charset
+
+
 class CustomJsonScanner(object):
     """
     This class is a context manager definition used to monkey patch the default