http: Only require Tornado >= 2.3

docs/changelog.rst

@@ -4,6 +4,15 @@ Changelog
 
 This changelog is used to track all major changes to Mopidy.
 
+v0.19.1 (UNRELEASED)
+====================
+
+**Dependencies**
+
+- Mopidy now requires Tornado >= 2.3, instead of >= 3.1. This should make
+  Mopidy continue to work on Debian/Raspbian stable, where Tornado 2.3 is the
+  newest version available.
+
 
 v0.19.0 (2014-07-21)
 ====================

mopidy/http/handlers.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 import logging
 import os
+import socket
 
 import tornado.escape
 import tornado.web
@@ -76,7 +77,12 @@ class WebSocketHandler(tornado.websocket.WebSocketHandler):
         self.jsonrpc = make_jsonrpc_wrapper(core)
 
     def open(self):
-        self.set_nodelay(True)
+        if hasattr(self, 'set_nodelay'):
+            # New in Tornado 3.1
+            self.set_nodelay(True)
+        else:
+            self.handler.connection.socket.setsockopt(
+                socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
         self.clients.add(self)
         logger.debug(
             'New WebSocket connection from %s', self.request.remote_ip)

setup.py

@@ -26,7 +26,7 @@ setup(
     install_requires=[
         'setuptools',
         'Pykka >= 1.1',
-        'tornado >= 3.1',
+        'tornado >= 2.3',
     ],
     extras_require={'http': []},
     test_suite='nose.collector',