Initial implementation of the Juju GUI server.

server/guiserver/handlers.py

Index: server/guiserver/handlers.py
=== added file 'server/guiserver/handlers.py'
--- server/guiserver/handlers.py	1970-01-01 00:00:00 +0000
+++ server/guiserver/handlers.py	2013-07-18 15:56:09 +0000
@@ -0,0 +1,87 @@
+# This file is part of the Juju GUI, which lets users view and manage Juju
+# environments within a graphical interface (https://launchpad.net/juju-gui).
+# Copyright (C) 2013 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License version 3, as published by
+# the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranties of MERCHANTABILITY,
+# SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Juju GUI server HTTP/HTTPS handlers."""
+
+import logging
+import os
+
+from tornado import (
+    gen,
+    web,
+    websocket,
+)
+
+from guiserver.clients import WebSocketClient
+
+
+class WebSocketHandler(websocket.WebSocketHandler):
+    """WebSocket handler supporting secure WebSockets.
+
+    This handler acts as a proxy between the browser connection and the
+    Juju API server.
+    """
+
+    @gen.coroutine
+    def initialize(self, jujuapi):
+        """Create a new WebSocket client and connect it to the Juju API."""
+        logging.debug('ws server: connecting to juju')
+        self.jujuconn = WebSocketClient(jujuapi, self.on_juju_message)
+        yield self.jujuconn.connect()
+        logging.debug('ws server: connected to juju')
+
+    def on_message(self, message):
+        """Hook called when a new message is received from the browser.
+
+        The message is propagated to the Juju API server.
+        """
+        logging.debug('ws server: browser --> juju: {}'.format(message))
+        self.jujuconn.write_message(message)
+
+    def on_juju_message(self, message):
+        """Hook called when a new message is received from the Juju API server.
+
+        The message is propagated to the browser.
+        """
+        logging.debug('ws server: juju --> browser: {}'.format(message))
+        self.write_message(message)
+
+    @gen.coroutine
+    def on_close(self):
+        """Hook called when the WebSocket connection is terminated."""
+        logging.debug('ws server: connection closed')
+        yield self.jujuconn.close()
+        self.jujuconn = None
+
+
+class IndexHandler(web.StaticFileHandler):
+    """Serve all requests using the index.html file placed in the static root.
+    """
+
+    @classmethod
+    def get_absolute_path(cls, root, path):
+        """See tornado.web.StaticFileHandler.get_absolute_path."""
+        return os.path.join(root, 'index.html')
+
+
+class HttpsRedirectHandler(web.RequestHandler):
+    """Permanently redirect all the requests to the equivalent HTTPS URL."""
+
+    def get(self):
+        """Handle GET requests."""
+        request = self.request
+        url = 'https://{}{}'.format(request.host, request.uri)
+        self.redirect(url, permanent=True)