Added RCon Observer

It does the rcons! And the observings!

overviewer_core/observer.py

@@ -19,6 +19,7 @@
 import sys
 import os
 import json
+import rcon
 
 class Observer(object):
     """Base class that defines the observer interface.
@@ -392,3 +393,43 @@ def _send_output(self, output):
         self.target_handle.write('say %s\n' % output)
         self.target_handle.flush()
 
+
+# Fair amount of code duplication incoming
+# Perhaps both ServerAnnounceObserver and RConObserver
+# could share the percentage interval code.
+
+class RConObserver(Observer):
+    """Send the output to a Minecraft server via rcon"""
+
+    def __init__(self, target, password, port=25575, pct_interval=10):
+        self.pct_interval = pct_interval
+        self.conn = rcon.RConConnection(target, port)
+        self.conn.login(password)
+        self.last_update = 0
+        super(RConObserver, self).__init__()
+
+    def start(self, max_value):
+        self._send_output("Starting render of %d total tiles" % max_value)
+        super(RConObserver, self).start(max_value)
+
+    def finish(self):
+        self._send_output("Render complete!")
+        super(RConObserver, self).finish()
+        self.conn.close()
+
+    def update(self, current_value):
+        super(RConObserver, self).update(current_value)
+        if self._need_update():
+            self._send_output('Rendered %d of %d tiles, %d%% complete' %
+                (self.get_current_value(), self.get_max_value(),
+                    self.get_percentage()))
+            self.last_update = current_value
+
+    def _need_update(self):
+        return self.get_percentage() - \
+            (self.last_update * 100.0 / self.get_max_value()) >= self.pct_interval
+
+    def _send_output(self, output):
+        self.conn.command("say", output)
+
+

overviewer_core/rcon.py

@@ -0,0 +1,95 @@
+#    This file is part of the Minecraft Overviewer.
+#
+#    Minecraft Overviewer is free software: you can redistribute it and/or
+#    modify it under the terms of the GNU General Public License as published
+#    by the Free Software Foundation, either version 3 of the License, or (at
+#    your option) any later version.
+#
+#    Minecraft Overviewer is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+#    Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License along
+#    with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+
+import socket
+#from enum import Enum
+import struct
+import select
+
+class RConException(Exception):
+    def __init__(self, request_id, reason):
+        self.request_id = request_id
+        self.reason = reason
+
+    def __str__(self):
+        return ("Failed RCon request with request ID %d, reason %s" %
+                (self.request_id, self.reason))
+
+# In D, enums are just that, enums. They're a group of named constants,
+# sometimes with a tag, sometimes anonymous.
+# In Python, Enums use the same syntax as class objects that derive from
+# the "Enum" base class, even though they are not normal python classes
+# and work as singletons anyway, but instead of using a different syntax,
+# Python instead decided to have a chapter in their docs about how Enums
+# are different from regular classes while looking exactly the same.
+# You can look at said document of failure right here:
+# https://docs.python.org/3/library/enum.html#how-are-enums-different
+#
+# "D has too much shit going on for me" -- agrif, 2014
+#
+# Fortunately, we're not allowed to use Enums in Python 2.
+
+#class RConType(Enum):
+#    command = 2
+#    login = 3
+
+
+class RConConnection():
+    rid = 0
+
+    def __init__(self, target, port):
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.connect((target, port))
+
+    def send(self, t, payload):
+        self.rid = self.rid + 1
+        header = struct.pack("<iii",
+                len(payload) + 4 + 4 + 2,    # rid, type and padding
+                self.rid,
+                t)
+        data = header + payload + '\x00\x00'
+        self.sock.send(data)
+
+
+        toread = select.select([self.sock], [], [], 30)
+
+        if not toread:
+            raise RConException(self.rid, "Request timed out.")
+
+        res_len, res_id, res_type = struct.unpack("<iii", self.sock.recv(12))
+        res_data = self.sock.recv(res_len - 4 - 4)
+        res_data = res_data[:-2]
+
+        if res_id == -1:
+            if t == 3:
+                raise RConException(self.rid, "Login failed.")
+            else:
+                raise RConException(self.rid, "Request failed due to invalid login.")
+        elif res_id != self.rid:
+            raise RConException(self.rid,
+                                "Received unexpected response number: %d" % res_id)
+
+        return res_data
+
+
+
+    def login(self, password):
+        self.send(3, password)
+
+    def command(self, com, args):
+        self.send(2, com + " " + args)
+
+    def close(self):
+        self.sock.close()