Implement LIST HEADERS

lib/nntp/tiny/session.py

@@ -406,11 +406,26 @@ class Session():
 
         return self.end()
 
+    SUPPORTED_HEADERS = [
+        ':',
+        ':lines',
+        ':bytes',
+    ]
+
+    def _cmd_list_headers(self):
+        self.respond(ResponseCode.NNTP_INFORMATION_FOLLOWS, "metadata items supported")
+
+        for name in self.SUPPORTED_HEADERS:
+            self.print(name)
+
+        self.end()
+
     LIST_SUBCOMMANDS = {
         'NEWSGROUPS':   _cmd_list_newsgroups,
         'ACTIVE':       _cmd_list_active,
         'ACTIVE.TIMES': _cmd_list_active_times,
         'OVERVIEW.FMT': _cmd_list_overview_fmt,
+        'HEADERS':      _cmd_list_headers,
     }
 
     def _cmd_list(self, *args):