[FIX] mimetype

flectra/tools/mimetypes.py

@@ -179,7 +179,7 @@ else:
         _guesser = ms.buffer
 
     def guess_mimetype(bin_data, default=None):
-        mimetype = _guesser(bin_data)
+        mimetype = _guesser(bin_data[:1024])
         # upgrade incorrect mimetype to official one, fixed upstream
         # https://github.com/file/file/commit/1a08bb5c235700ba623ffa6f3c95938fe295b262
         if mimetype == 'image/svg':
@@ -191,3 +191,14 @@ def neuter_mimetype(mimetype, user):
     if wrong_type and not user._is_system():
         return 'text/plain'
     return mimetype
+
+
+def get_extension(filename):
+    """ Return the extension the current filename based on the heuristic that
+    ext is less than or equal to 10 chars and is alphanumeric.
+
+    :param str filename: filename to try and guess a extension for
+    :returns: detected extension or ``
+    """
+    ext = '.' in filename and filename.split('.')[-1]
+    return ext and len(ext) <= 10 and ext.isalnum() and '.' + ext.lower() or ''