mail: add a custom email policy

Uses structured parsing for more headers.

1 files changed, 19 insertions, 0 deletions

diff --git a/alot/mail/policy.py b/alot/mail/policy.py
new file mode 100644
index 00000000..1b9f07c3
--- /dev/null
+++ b/alot/mail/policy.py
@@ -0,0 +1,19 @@
+# This file is released under the GNU GPL, version 3 or a later revision.
+# For further details see the COPYING file
+
+import email.policy         as _p
+import email.headerregistry as _hdr
+
+from . import headers as HDR
+
+_headers = {
+    HDR.X_BEEN_THERE   : _hdr.UniqueAddressHeader,
+    HDR.X_MAILING_LIST : _hdr.UniqueAddressHeader,
+}
+
+# here we define our custom policy that handles additional headers
+# derive from SMTP
+p = _p.EmailPolicy() + _p.SMTP
+
+for h, t in _headers.items():
+    p.header_factory.map_to_type(h, t)