Add missing suppress_ga file to git.

evennia/server/portal/suppress_ga.py

@@ -0,0 +1,65 @@
+"""
+
+SUPPRESS-GO-AHEAD
+
+This supports suppressing or activating Evennia
+the GO-AHEAD telnet operation after every server reply.
+If the client sends no explicit DONT SUPRESS GO-AHEAD,
+Evennia will default to supressing it since many clients
+will fail to use it and has no knowledge of this standard.
+
+It can be activated explicitly with the ADDGOAHEAD option.
+
+http://www.faqs.org/rfcs/rfc858.html
+
+"""
+from builtins import object
+SUPPRESS_GA = chr(3)
+
+# default taken from telnet specification
+
+# try to get the customized mssp info, if it exists.
+
+class SuppressGA(object):
+    """
+    Implements the SUPRESS-GO-AHEAD protocol. Add this to a variable on the telnet
+    protocol to set it up.
+
+    """
+    def __init__(self, protocol):
+        """
+        Initialize suppression of GO-AHEADs.
+
+        Args:
+            protocol (Protocol): The active protocol instance.
+
+        """
+        self.protocol = protocol
+
+        self.protocol.protocol_flags["NOGOAHEAD"] = True
+        # tell the client that we prefer to suppress GA ...
+        self.protocol.will(SUPPRESS_GA).addCallbacks(self.do_suppress_ga, self.dont_suppress_ga)
+        # ... but also accept if the client really wants not to.
+        self.protocol.do(SUPPRESS_GA).addCallbacks(self.do_suppress_ga, self.dont_suppress_ga)
+
+    def dont_suppress_ga(self, option):
+        """
+        Called when client requests to not suppress GA.
+
+        Args:
+            option (Option): Not used.
+
+        """
+        self.protocol.protocol_flags["NOGOAHEAD"] = False
+        self.protocol.handshake_done()
+
+    def do_suppress_ga(self, option):
+        """
+        Client wants to suppress GA
+
+        Args:
+            option (Option): Not used.
+
+        """
+        self.protocol.protocol_flags["NOGOAHEAD"] = True
+        self.protocol.handshake_done()