updated get_encoding_from_headers to return utf-8 if the content type is set to application/json, following RFC 4627.

fixes #5667

Author: jjmaldonis

requests/utils.py

@@ -503,6 +503,10 @@ def get_encoding_from_headers(headers):
     if 'text' in content_type:
         return 'ISO-8859-1'
 
+    if 'application/json' in content_type:
+        # Assume UTF-8 based on RFC 4627: https://www.ietf.org/rfc/rfc4627.txt since the charset was unset
+        return 'utf-8'
+
 
 def stream_decode_response_unicode(iterator, r):
     """Stream decodes a iterator."""