diff --git a/chatmaild/src/chatmaild/metadata.py b/chatmaild/src/chatmaild/metadata.py
index 52152cc2..f11027ae 100644
--- a/chatmaild/src/chatmaild/metadata.py
+++ b/chatmaild/src/chatmaild/metadata.py
@@ -22,54 +22,59 @@ def handle_dovecot_protocol(rfile, wfile, tokens, requests_session, config: Conf
         if not msg:
             break
 
-        short_command = msg[0]
-        if short_command == "L":
-            wfile.write(b"N\n")
-        elif short_command == "S":
-            # See header of
-            # <https://github.com/dovecot/core/blob/5e7965632395793d9355eb906b173bf28d2a10ca/src/lib-storage/mailbox-attribute.h>
-            # for the documentation on the structure of the key.
+        res = handle_dovecot_request(msg, tokens, requests_session, config)
+        if res:
+            wfile.write(res.encode("ascii"))
+            wfile.flush()
 
-            # Request GETMETADATA "INBOX" /private/chatmail
-            # results in a query for
-            # priv/dd72550f05eadc65542a1200cac67ad7/chatmail
-            #
-            # Request GETMETADATA "" /private/chatmail
-            # results in
-            # priv/dd72550f05eadc65542a1200cac67ad7/vendor/vendor.dovecot/pvt/server/chatmail
 
-            parts = msg[1:].split("\t")
-            transaction_id = parts[0]
-            keyname = parts[1].split("/")
-            value = parts[2] if len(parts) > 2 else ""
-            if keyname[0] == "priv" and keyname[2] == "devicetoken":
-                tokens[keyname[1]] = value
-            elif keyname[0] == "priv" and keyname[2] == "messagenew":
-                guid = keyname[1]
-                token = tokens.get(guid)
-                if token:
-                    response = requests_session.post(
-                        "https://notifications.delta.chat/notify",
-                        data=token,
-                        timeout=60,
-                    )
-                    if response.status_code == 410:
-                        # 410 Gone status code
-                        # means the token is no longer valid.
-                        del tokens[guid]
-            else:
-                # Transaction failed.
-                transactions[transaction_id] = b"F\n"
-        elif short_command == "B":
-            # Begin transaction.
-            transaction_id = msg[1:].split("\t")[0]
-            transactions[transaction_id] = b"O\n"
-        elif short_command == "C":
-            # Commit transaction.
-            transaction_id = msg[1:].split("\t")[0]
-            wfile.write(transactions.pop(transaction_id, b"N\n"))
+def handle_dovecot_request(msg, tokens, requests_session, config: Config):
+    short_command = msg[0]
+    if short_command == "L":
+        return b"N\n"
+    elif short_command == "S":
+        # See header of
+        # <https://github.com/dovecot/core/blob/5e7965632395793d9355eb906b173bf28d2a10ca/src/lib-storage/mailbox-attribute.h>
+        # for the documentation on the structure of the key.
 
-        wfile.flush()
+        # Request GETMETADATA "INBOX" /private/chatmail
+        # results in a query for
+        # priv/dd72550f05eadc65542a1200cac67ad7/chatmail
+        #
+        # Request GETMETADATA "" /private/chatmail
+        # results in
+        # priv/dd72550f05eadc65542a1200cac67ad7/vendor/vendor.dovecot/pvt/server/chatmail
+
+        parts = msg[1:].split("\t")
+        transaction_id = parts[0]
+        keyname = parts[1].split("/")
+        value = parts[2] if len(parts) > 2 else ""
+        if keyname[0] == "priv" and keyname[2] == "devicetoken":
+            tokens[keyname[1]] = value
+        elif keyname[0] == "priv" and keyname[2] == "messagenew":
+            guid = keyname[1]
+            token = tokens.get(guid)
+            if token:
+                response = requests_session.post(
+                    "https://notifications.delta.chat/notify",
+                    data=token,
+                    timeout=60,
+                )
+                if response.status_code == 410:
+                    # 410 Gone status code
+                    # means the token is no longer valid.
+                    del tokens[guid]
+        else:
+            # Transaction failed.
+            transactions[transaction_id] = b"F\n"
+    elif short_command == "B":
+        # Begin transaction.
+        transaction_id = msg[1:].split("\t")[0]
+        transactions[transaction_id] = b"O\n"
+    elif short_command == "C":
+        # Commit transaction.
+        transaction_id = msg[1:].split("\t")[0]
+        return transactions.pop(transaction_id, b"N\n")
 
 
 class ThreadedUnixStreamServer(ThreadingMixIn, UnixStreamServer):