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Posted to commits@qpid.apache.org by gs...@apache.org on 2014/12/12 12:53:37 UTC

[2/2] qpid-proton git commit: Initial set of engine examples along with supporting additions to the library.

Initial set of engine examples along with supporting additions to the library.


Project: http://git-wip-us.apache.org/repos/asf/qpid-proton/repo
Commit: http://git-wip-us.apache.org/repos/asf/qpid-proton/commit/34e64e32
Tree: http://git-wip-us.apache.org/repos/asf/qpid-proton/tree/34e64e32
Diff: http://git-wip-us.apache.org/repos/asf/qpid-proton/diff/34e64e32

Branch: refs/heads/master
Commit: 34e64e3248b67971b701d990709920fa690c12b4
Parents: 9a72a30
Author: Gordon Sim <gs...@redhat.com>
Authored: Fri Dec 5 20:49:54 2014 +0000
Committer: Gordon Sim <gs...@redhat.com>
Committed: Fri Dec 12 11:04:53 2014 +0000

----------------------------------------------------------------------
 examples/engine/py/README                       | 155 ++++
 examples/engine/py/abstract_server.py           |  35 +
 examples/engine/py/client.py                    |  59 ++
 examples/engine/py/client_http.py               | 110 +++
 examples/engine/py/common.py                    | 699 ++++++++++++++++
 examples/engine/py/db_common.py                 |  93 +++
 examples/engine/py/db_ctrl.py                   |  46 ++
 examples/engine/py/db_recv.py                   |  54 ++
 examples/engine/py/db_send.py                   |  85 ++
 examples/engine/py/helloworld.py                |  45 +
 examples/engine/py/helloworld_blocking.py       |  35 +
 examples/engine/py/helloworld_direct.py         |  47 ++
 examples/engine/py/helloworld_direct_tornado.py |  52 ++
 examples/engine/py/helloworld_tornado.py        |  49 ++
 examples/engine/py/proton_server.py             |  61 ++
 examples/engine/py/proton_tornado.py            |  70 ++
 examples/engine/py/recurring_timer.py           |  43 +
 examples/engine/py/recurring_timer_tornado.py   |  44 +
 examples/engine/py/selected_recv.py             |  40 +
 examples/engine/py/server.py                    |  56 ++
 examples/engine/py/server_tx.py                 |  77 ++
 examples/engine/py/simple_recv.py               |  40 +
 examples/engine/py/simple_send.py               |  53 ++
 examples/engine/py/sync_client.py               |  88 ++
 examples/engine/py/tx_recv.py                   |  61 ++
 examples/engine/py/tx_recv_interactive.py       |  83 ++
 examples/engine/py/tx_send.py                   |  75 ++
 examples/engine/py/tx_send_sync.py              |  76 ++
 proton-c/bindings/python/CMakeLists.txt         |  20 +-
 proton-c/bindings/python/proton/__init__.py     |  63 +-
 proton-c/bindings/python/proton/handlers.py     | 440 ++++++++++
 proton-c/bindings/python/proton/reactors.py     | 827 +++++++++++++++++++
 proton-c/bindings/python/proton/utils.py        | 114 +++
 33 files changed, 3870 insertions(+), 25 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/README
----------------------------------------------------------------------
diff --git a/examples/engine/py/README b/examples/engine/py/README
new file mode 100644
index 0000000..a361fc4
--- /dev/null
+++ b/examples/engine/py/README
@@ -0,0 +1,155 @@
+Most (though not all) of the current examples require a broker or
+similar intermediary that supports the AMQP 1.0 protocol, allows
+anonymous connections and accepts links to and from a node named
+'examples'.
+
+------------------------------------------------------------------
+
+helloworld.py
+
+Basic example that connects to an intermediary on localhost:5672,
+establishes a subscription from the 'examples' node on that
+intermediary, then creates a sending link to the same node and sends
+one message. On receving the message back via the subcription, the
+connection is closed.
+
+helloworld_blocking.py
+
+The same as the basic helloworld.py, but using a
+synchronous/sequential style wrapper on top of the
+asynchronous/reactive API. The purpose of this example is just to show
+how different functionality can be easily layered should it be
+desired.
+
+helloworld_direct.py
+
+A variant of the basic hellpwprld example, that does not use an
+intermediary, but listens for incoming connections itself. It
+establishes a connection to itself with a link over which a single
+message is sent. This demonstrates the ease with which a simple daemon
+can be built using the API.
+
+helloworld_tornado.py
+helloworld_direct_tornado.py
+
+These are variant of the helloworld.py and helloworld_direct.py
+examples that use the event loop from the tornado library, rather than
+that provided within proton itself and demonstrate how proton can be
+used with external loops.
+
+-------------------------------------------------------------------
+
+simple_send.py
+
+An example of sending a fixed number of messages and tracking their
+(asynchronous) acknowledgement. Handles disconnection while
+maintaining an at-least-once guarantee (there may be duplicates, but
+no message in the sequence should be lost). Messages are sent through
+the 'examples' node on an intermediary accessible on port 5672 on
+localhost.
+
+simple_recv.py
+
+Subscribes to the 'examples' node on an intermediary accessible on port 5672 on
+localhost. Simply prints out the body of received messages.
+
+db_send.py
+
+A more realistic sending example, where the messages come from records
+in a simple database table. On being acknowledged the records can be
+deleted from the table. The database access is done in a separate
+thread, so as not to block the event thread during data
+access. Messages are sent through the 'examples' node on an
+intermediary accessible on port 5672 on localhost.
+
+db_recv.py
+
+A receiving example that records messages received from the 'examples'
+node on localhost:5672 in a database table and only acknowledges them
+when the insert completes. Database access is again done in a separate
+thread from the event loop.
+
+db_ctrl.py
+
+A utility for setting up the database tables for the two examples
+above. Takes two arguments, the action to perform and the name of the
+database on which to perfom it. The database used by db_send.py is
+src_db, that by db_recv.py is dst_db. The valid actions are 'init',
+which creates the table, 'list' which displays the contents and
+'insert' which inserts records from standard-in and is used to
+populate src_db, e.g. for i in `seq 1 50`; do echo "Message-$i"; done
+| ./db_ctrl.py insert src_db.
+
+tx_send.py
+
+A sender that sends messages in atomic batches using local
+transactions (this example does not persist the messages in anyway).
+
+tx_send_sync.py
+
+A variant of the former example that waits for all messages in a batch
+to be acknowledged before committing. Used only to work around an
+ordering issue in preoton that affected qpidd.
+
+tx_recv.py
+
+A receiver example that accepts batches of messages using local
+transactions.
+
+tx_recv_interactive.py
+
+A testing utility that allow interactive control of the
+transactions. Actions are keyed in to the console, 'fetch' will
+request another message, 'abort' will abort the transaction, 'commit'
+will commit it.
+
+The various send/recv examples can be mixed and matched if desired.
+
+-------------------------------------------------------------------
+
+client.py
+
+The client part of a request-response example. Sends requests and
+prints out responses. Requires an intermediary that support the AMQP
+1.0 dynamic nodes on which the responses are received. The requests
+are sent through the 'examples' node.
+
+server.py
+
+The server part of a request-response example, that receives requests
+via the examples node, converts the body to uppercase and sends the
+result back to the indicated reply address.
+
+sync_client.py
+
+A variant of the client part, that uses a blocking/synchronous style
+instead of the reactive/asynchronous style.
+
+client_http.py
+
+A variant of the client part that takes the input to be submitted in
+the request over HTTP (point your browser to localhost:8888/client)
+
+server_tx.py
+
+A variant of the server part that consumes the request and sends out
+the response atomically in a local transaction.
+
+-------------------------------------------------------------------
+
+selected_recv.py
+
+An example that uses a selector filter.
+
+-------------------------------------------------------------------
+
+recurring_timer.py
+
+An example showing a simple timer event.
+
+recurring_timer_tornado.py
+
+A variant of the above that uses the tornado eventloop instead.
+
+-------------------------------------------------------------------
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/abstract_server.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/abstract_server.py b/examples/engine/py/abstract_server.py
new file mode 100755
index 0000000..2d0de32
--- /dev/null
+++ b/examples/engine/py/abstract_server.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton_server import Server
+
+class Application(Server):
+    def __init__(self, host, address):
+        super(Application, self).__init__(host, address)
+
+    def on_request(self, request, reply_to):
+        response = request.upper()
+        self.send(response, reply_to)
+        print "Request from: %s" % reply_to
+
+try:
+    Application("localhost:5672", "examples").run()
+except KeyboardInterrupt: pass
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/client.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/client.py b/examples/engine/py/client.py
new file mode 100755
index 0000000..d1e2706
--- /dev/null
+++ b/examples/engine/py/client.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton.reactors import Container
+
+class Client(MessagingHandler):
+    def __init__(self, host, address, requests):
+        super(Client, self).__init__()
+        self.host = host
+        self.address = address
+        self.requests = requests
+
+    def on_start(self, event):
+        self.conn = event.container.connect(self.host)
+        self.sender = event.container.create_sender(self.conn, self.address)
+        self.receiver = event.container.create_receiver(self.conn, None, dynamic=True)
+
+    def next_request(self):
+        if self.receiver.remote_source.address:
+            req = Message(reply_to=self.receiver.remote_source.address, body=self.requests[0])
+            self.sender.send_msg(req)
+
+    def on_link_opened(self, event):
+        if event.receiver == self.receiver:
+            self.next_request()
+
+    def on_message(self, event):
+        print "%s => %s" % (self.requests.pop(0), event.message.body)
+        if self.requests:
+            self.next_request()
+        else:
+            self.conn.close()
+
+REQUESTS= ["Twas brillig, and the slithy toves",
+           "Did gire and gymble in the wabe.",
+           "All mimsy were the borogroves,",
+           "And the mome raths outgrabe."]
+
+Container(Client("localhost:5672", "examples", REQUESTS)).run()
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/client_http.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/client_http.py b/examples/engine/py/client_http.py
new file mode 100755
index 0000000..5202f8d
--- /dev/null
+++ b/examples/engine/py/client_http.py
@@ -0,0 +1,110 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton_tornado import TornadoLoop
+from tornado.ioloop import IOLoop
+import tornado.web
+
+class Client(MessagingHandler):
+    def __init__(self, host, address):
+        super(Client, self).__init__()
+        self.host = host
+        self.address = address
+        self.sent = []
+        self.pending = []
+        self.reply_address = None
+        self.sender = None
+        self.receiver = None
+
+    def on_start(self, event):
+        conn = event.container.connect(self.host)
+        self.sender = event.container.create_sender(conn, self.address)
+        self.receiver = event.container.create_receiver(conn, None, dynamic=True)
+
+    def on_link_opened(self, event):
+        if event.receiver == self.receiver:
+            self.reply_address = event.link.remote_source.address
+            self.do_request()
+
+    def on_credit(self, event):
+        self.do_request()
+
+    def on_message(self, event):
+        if self.sent:
+            request, handler = self.sent.pop(0)
+            print "%s => %s" % (request, event.message.body)
+            handler(event.message.body)
+            self.do_request()
+
+    def do_request(self):
+        if self.pending and self.reply_address and self.sender.credit:
+            request, handler = self.pending.pop(0)
+            self.sent.append((request, handler))
+            req = Message(reply_to=self.reply_address, body=request)
+            self.sender.send_msg(req)
+
+    def request(self, body, handler):
+        self.pending.append((body, handler))
+        self.do_request()
+
+class ExampleHandler(tornado.web.RequestHandler):
+    def initialize(self, client):
+        self.client = client
+
+    def get(self):
+        self._write_open()
+        self._write_form()
+        self._write_close()
+
+    @tornado.web.asynchronous
+    def post(self):
+        client.request(self.get_body_argument("message"), lambda x: self.on_response(x))
+
+    def on_response(self, body):
+        self.set_header("Content-Type", "text/html")
+        self._write_open()
+        self._write_form()
+        self.write("Response: " + body)
+        self._write_close()
+        self.finish()
+
+    def _write_open(self):
+        self.write('<html><body>')
+
+    def _write_close(self):
+        self.write('</body></html>')
+
+    def _write_form(self):
+        self.write('<form action="/client" method="POST">'
+                   'Request: <input type="text" name="message">'
+                   '<input type="submit" value="Submit">'
+                   '</form>')
+
+
+client = Client("localhost:5672", "examples")
+loop = TornadoLoop(client)
+app = tornado.web.Application([tornado.web.url(r"/client", ExampleHandler, dict(client=client))])
+app.listen(8888)
+try:
+    loop.run()
+except KeyboardInterrupt:
+    loop.stop()

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/common.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/common.py b/examples/engine/py/common.py
new file mode 100644
index 0000000..d4d9a69
--- /dev/null
+++ b/examples/engine/py/common.py
@@ -0,0 +1,699 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+import errno, os, random, select, time, traceback
+from proton import *
+from socket import *
+from threading import Thread
+from heapq import heappush, heappop, nsmallest
+
+class Selectable:
+
+    def __init__(self, transport, socket):
+        self.transport = transport
+        self.socket = socket
+        self.write_done = False
+        self.read_done = False
+
+    def closed(self):
+        if self.write_done and self.read_done:
+            self.socket.close()
+            return True
+        else:
+            return False
+
+    def fileno(self):
+        return self.socket.fileno()
+
+    def reading(self):
+        if self.read_done: return False
+        c = self.transport.capacity()
+        if c > 0:
+            return True
+        elif c < 0:
+            self.read_done = True
+            return False
+
+    def writing(self):
+        if self.write_done: return False
+        try:
+            p = self.transport.pending()
+            if p > 0:
+                return True
+            elif p < 0:
+                self.write_done = True
+                return False
+        except TransportException, e:
+            self.write_done = True
+            return False
+
+    def readable(self):
+        c = self.transport.capacity()
+        if c > 0:
+            try:
+                data = self.socket.recv(c)
+                if data:
+                    self.transport.push(data)
+                else:
+                    self.transport.close_tail()
+            except error, e:
+                print "read error", e
+                self.transport.close_tail()
+                self.read_done = True
+        elif c < 0:
+            self.read_done = True
+
+    def writable(self):
+        try:
+            p = self.transport.pending()
+            if p > 0:
+                data = self.transport.peek(p)
+                n = self.socket.send(data)
+                self.transport.pop(n)
+            elif p < 0:
+                self.write_done = True
+        except error, e:
+            print "write error", e
+            self.transport.close_head()
+            self.write_done = True
+
+    def tick(self, now):
+        return self.transport.tick(now)
+
+class Acceptor:
+
+    def __init__(self, driver, host, port):
+        self.driver = driver
+        self.socket = socket()
+        self.socket.setblocking(0)
+        self.socket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
+        self.socket.bind((host, port))
+        self.socket.listen(5)
+        self.driver.add(self)
+
+    def closed(self):
+        return False
+
+    def fileno(self):
+        return self.socket.fileno()
+
+    def reading(self):
+        return True
+
+    def writing(self):
+        return False
+
+    def readable(self):
+        sock, addr = self.socket.accept()
+        sock.setblocking(0)
+        print "Incoming Connection:", addr
+        if sock:
+            conn = Connection()
+            conn.collect(self.driver.collector)
+            transport = Transport()
+            transport.bind(conn)
+            sasl = transport.sasl()
+            sasl.mechanisms("ANONYMOUS")
+            sasl.server()
+            sasl.done(SASL.OK)
+            sel = Selectable(transport, sock)
+            self.driver.add(sel)
+
+    def tick(self, now):
+        return None
+
+class Interrupter:
+
+    def __init__(self):
+        self.read, self.write = os.pipe()
+
+    def fileno(self):
+        return self.read
+
+    def readable(self):
+        os.read(self.read, 1024)
+
+    def interrupt(self):
+        os.write(self.write, 'x')
+
+class PQueue:
+
+    def __init__(self):
+        self.entries = []
+
+    def add(self, task, priority):
+        heappush(self.entries, (priority, task))
+
+    def peek(self):
+        if self.entries:
+            return nsmallest(1, self.entries)[0]
+        else:
+            return None
+
+    def pop(self):
+        if self.entries:
+            return heappop(self.entries)
+        else:
+            return None
+
+    def __nonzero__(self):
+        if self.entries:
+            return True
+        else:
+            return False
+
+import proton
+
+TIMER_EVENT = proton.EventType(10000, "on_timer")
+
+class Timer:
+
+    def __init__(self, collector):
+        self.collector = collector
+        self.tasks = PQueue()
+
+    def schedule(self, task, deadline):
+        self.tasks.add(task, deadline)
+
+    def tick(self, now):
+        while self.tasks:
+            deadline, task = self.tasks.peek()
+            if now > deadline:
+                self.tasks.pop()
+                self.collector.put(task, TIMER_EVENT)
+            else:
+                return deadline
+
+def _dispatch(ev, handler):
+    if ev.clazz == "pn_delivery" and ev.context.released:
+        return
+    else:
+        ev.dispatch(handler)
+
+def _expand(handlers):
+    result = []
+    for h in handlers:
+        if hasattr(h, "handlers"):
+            result.extend(h.handlers)
+        else:
+            result.append(h)
+    return result
+
+class Driver(Handler):
+
+    def __init__(self, *handlers):
+        self.collector = Collector()
+        self.handlers = _expand(handlers)
+        self.interrupter = Interrupter()
+        self.timer = Timer(self.collector)
+        self.selectables = []
+        self.now = None
+        self.deadline = None
+        self._abort = False
+        self._exit = False
+        self._thread = Thread(target=self.run)
+        self._thread.setDaemon(True)
+
+    def schedule(self, task, timeout):
+        self.timer.schedule(task, self.now + timeout)
+
+    def abort(self):
+        self._abort = True
+
+    def exit(self):
+        self._exit = True
+
+    def wakeup(self):
+        self.interrupter.interrupt()
+
+    def start(self):
+        self._thread.start()
+
+    def join(self):
+        self._thread.join()
+
+    def _init_deadline(self):
+        self.now = time.time()
+        self.deadline = None
+
+    def _update_deadline(self, t):
+        if t is None or t < self.now: return
+        if self.deadline is None or t < self.deadline:
+            self.deadline = t
+
+    @property
+    def _timeout(self):
+        if self.deadline is None:
+            return None
+        else:
+            return self.deadline - self.now
+
+    def run(self):
+        self._init_deadline()
+        for h in self.handlers:
+            dispatch(h, "on_start", self)
+
+        while True:
+            self._init_deadline()
+
+            while True:
+                self.process_events()
+                if self._abort: return
+                self._update_deadline(self.timer.tick(self.now))
+                count = self.process_events()
+                if self._abort: return
+                if not count:
+                    break
+
+            reading = [self.interrupter]
+            writing = []
+
+            for s in self.selectables[:]:
+                if s.reading(): reading.append(s)
+                if s.writing(): writing.append(s)
+                self._update_deadline(s.tick(self.now))
+                if s.closed(): self.selectables.remove(s)
+
+            if self._exit and not self.selectables: return
+
+            try:
+                readable, writable, _ = select.select(reading, writing, [], self._timeout)
+            except select.error, (err, errtext):
+                if err == errno.EINTR:
+                    continue
+                else:
+                    raise
+
+            for s in readable:
+                s.readable()
+            for s in writable:
+                s.writable()
+
+    def process_events(self):
+        count = 0
+
+        quiesced = False
+        while True:
+            ev = self.collector.peek()
+            if ev:
+                count += 1
+                quiesced = False
+                _dispatch(ev, self)
+                for h in self.get_handlers(ev.context):
+                    _dispatch(ev, h)
+                self.collector.pop()
+            elif quiesced:
+                return count
+            else:
+                for h in self.handlers:
+                    dispatch(h, "on_quiesced", self)
+                quiesced = True
+
+        return count
+
+    getters = {
+        Transport: lambda x: x.connection,
+        Delivery: lambda x: x.link,
+        Sender: lambda x: x.session,
+        Receiver: lambda x: x.session,
+        Session: lambda x: x.connection,
+    }
+
+    def get_handlers(self, context):
+        if hasattr(context, "handlers"):
+            return context.handlers
+        elif context.__class__ in self.getters:
+            parent = self.getters[context.__class__](context)
+            return self.get_handlers(parent)
+        else:
+            return self.handlers
+
+    def on_connection_local_open(self, event):
+        conn = event.context
+        if conn.state & Endpoint.REMOTE_UNINIT:
+            self._connect(conn)
+
+    def _connect(self, conn):
+        transport = Transport()
+        transport.idle_timeout = 300
+        sasl = transport.sasl()
+        sasl.mechanisms("ANONYMOUS")
+        sasl.client()
+        transport.bind(conn)
+        sock = socket()
+        sock.setblocking(0)
+        hostport = conn.hostname.split(":", 1)
+        host = hostport[0]
+        if len(hostport) > 1:
+            port = int(hostport[1])
+        else:
+            port = 5672
+        sock.connect_ex((host, port))
+        selectable = Selectable(transport, sock)
+        self.add(selectable)
+
+    def on_timer(self, event):
+        event.context()
+
+    def connection(self, *handlers):
+        conn = Connection()
+        if handlers:
+            conn.handlers = _expand(handlers)
+        conn.collect(self.collector)
+        return conn
+
+    def acceptor(self, host, port):
+        return Acceptor(self, host, port)
+
+    def add(self, selectable):
+        self.selectables.append(selectable)
+
+class Handshaker(Handler):
+
+    def on_connection_remote_open(self, event):
+        conn = event.context
+        if conn.state & Endpoint.LOCAL_UNINIT:
+            conn.open()
+
+    def on_session_remote_open(self, event):
+        ssn = event.context
+        if ssn.state & Endpoint.LOCAL_UNINIT:
+            ssn.open()
+
+    def on_link_remote_open(self, event):
+        link = event.context
+        if link.state & Endpoint.LOCAL_UNINIT:
+            link.source.copy(link.remote_source)
+            link.target.copy(link.remote_target)
+            link.open()
+
+    def on_connection_remote_close(self, event):
+        conn = event.context
+        if not (conn.state & Endpoint.LOCAL_CLOSED):
+            conn.close()
+
+    def on_session_remote_close(self, event):
+        ssn = event.context
+        if not (ssn.state & Endpoint.LOCAL_CLOSED):
+            ssn.close()
+
+    def on_link_remote_close(self, event):
+        link = event.context
+        if not (link.state & Endpoint.LOCAL_CLOSED):
+            link.close()
+
+class FlowController(Handler):
+
+    def __init__(self, window):
+        self.window = window
+
+    def top_up(self, link):
+        delta = self.window - link.credit
+        link.flow(delta)
+
+    def on_link_local_open(self, event):
+        link = event.context
+        if link.is_receiver:
+            self.top_up(link)
+
+    def on_link_remote_open(self, event):
+        link = event.context
+        if link.is_receiver:
+            self.top_up(link)
+
+    def on_link_flow(self, event):
+        link = event.context
+        if link.is_receiver:
+            self.top_up(link)
+
+    def on_delivery(self, event):
+        delivery = event.context
+        if delivery.link.is_receiver:
+            self.top_up(delivery.link)
+
+class Row:
+
+    def __init__(self):
+        self.links = set()
+
+    def add(self, link):
+        self.links.add(link)
+
+    def discard(self, link):
+        self.links.discard(link)
+
+    def choose(self):
+        if self.links:
+            return random.choice(list(self.links))
+        else:
+            return None
+
+    def __iter__(self):
+        return iter(self.links)
+
+    def __nonzero__(self):
+        return bool(self.links)
+
+
+class Router(Handler):
+
+    EMPTY = Row()
+
+    def __init__(self):
+        self._outgoing = {}
+        self._incoming = {}
+
+    def incoming(self, address):
+        return self._incoming.get(address, self.EMPTY)
+
+    def outgoing(self, address):
+        return self._outgoing.get(address, self.EMPTY)
+
+    def address(self, link):
+        if link.is_sender:
+            return link.source.address or link.target.address
+        else:
+            return link.target.address
+
+    def table(self, link):
+        if link.is_sender:
+            return self._outgoing
+        else:
+            return self._incoming
+
+    def add(self, link):
+        address = self.address(link)
+        table = self.table(link)
+        row = table.get(address)
+        if row is None:
+            row = Row()
+            table[address] = row
+        row.add(link)
+
+    def remove(self, link):
+        address = self.address(link)
+        table = self.table(link)
+        row = table.get(address)
+        if row is not None:
+            row.discard(link)
+            if not row:
+                del table[address]
+
+    def on_link_local_open(self, event):
+        self.add(event.context)
+
+    def on_link_local_close(self, event):
+        self.remove(event.context)
+
+    def on_link_final(self, event):
+        self.remove(event.context)
+
+class Pool(Handler):
+
+    def __init__(self, collector, router=None):
+        self.collector = collector
+        self._connections = {}
+        if router:
+            self.outgoing_resolver = lambda address: router.outgoing(address).choose()
+            self.incoming_resolver = lambda address: router.incoming(address).choose()
+        else:
+            self.outgoing_resolver = lambda address: None
+            self.incoming_resolver = lambda address: None
+
+    def resolve(self, remote, local, resolver, constructor):
+        link = resolver(remote)
+        if link is None:
+            host = remote[2:].split("/", 1)[0]
+            conn = self._connections.get(host)
+            if conn is None:
+                conn = Connection()
+                conn.collect(self.collector)
+                conn.hostname = host
+                conn.open()
+                self._connections[host] = conn
+
+            ssn = conn.session()
+            ssn.open()
+            link = constructor(ssn, remote, local)
+            link.open()
+        return link
+
+    def on_transport_closed(self, event):
+        transport =  event.context
+        conn = transport.connection
+        del self._connections[conn.hostname]
+
+    def outgoing(self, target, source=None):
+        return self.resolve(target, source, self.outgoing_resolver, self.new_outgoing)
+
+    def incoming(self, source, target=None):
+        return self.resolve(source, target, self.incoming_resolver, self.new_incoming)
+
+    def new_outgoing(self, ssn, remote, local):
+        snd = ssn.sender("%s-%s" % (local, remote))
+        snd.source.address = local
+        snd.target.address = remote
+        return snd
+
+    def new_incoming(self, ssn, remote, local):
+        rcv = ssn.receiver("%s-%s" % (remote, local))
+        rcv.source.address = remote
+        rcv.target.address = local
+        return rcv
+
+class MessageDecoder(Handler):
+
+    def __init__(self, delegate):
+        self.__delegate = delegate
+
+    def on_start(self, drv):
+        try:
+            self.__delegate
+        except AttributeError:
+            self.__delegate = self
+        self.__message = Message()
+
+    def on_delivery(self, event):
+        dlv = event.context
+        if dlv.link.is_receiver and not dlv.partial:
+            encoded = dlv.link.recv(dlv.pending)
+            self.__message.decode(encoded)
+            try:
+                dispatch(self.__delegate, "on_message", dlv.link, self.__message)
+                dlv.update(Delivery.ACCEPTED)
+            except:
+                dlv.update(Delivery.REJECTED)
+                traceback.print_exc()
+            dlv.settle()
+
+class Address:
+
+    def __init__(self, st):
+        self.st = st
+
+    @property
+    def host(self):
+        return self.st[2:].split("/", 1)[0]
+
+    @property
+    def path(self):
+        parts = self.st[2:].split("/", 1)
+        if len(parts) == 2:
+            return parts[1]
+        else:
+            return ""
+
+    def __repr__(self):
+        return "Address(%r)" % self.st
+
+    def __str__(self):
+        return self.st
+
+class SendQueue(Handler):
+
+    def __init__(self, address):
+        self.address = Address(address)
+        self.messages = []
+        self.sent = 0
+
+    def on_start(self, drv):
+        self.driver = drv
+        self.connect()
+
+    def connect(self):
+        self.conn = self.driver.connection(self)
+        self.conn.hostname = self.address.host
+        ssn = self.conn.session()
+        snd = ssn.sender(str(self.address))
+        snd.target.address = str(self.address)
+        ssn.open()
+        snd.open()
+        self.conn.open()
+        self.link = snd
+
+    def put(self, message):
+        self.messages.append(message.encode())
+        if self.link:
+            self.pump(self.link)
+
+    def on_link_flow(self, event):
+        link = event.context
+        self.pump(link)
+
+    def pump(self, link):
+        while self.messages and link.credit > 0:
+            dlv = link.delivery(str(self.sent))
+            bytes = self.messages.pop(0)
+            link.send(bytes)
+            dlv.settle()
+            self.sent += 1
+
+    def on_transport_closed(self, event):
+        conn = event.context.connection
+        self.conn = None
+        self.link = None
+        self.driver.schedule(self.connect, 1)
+
+# XXX: terrible name for this
+class RecvQueue(Handler):
+
+    def __init__(self, address, delegate):
+        self.address = Address(address)
+        self.delegate = delegate
+        self.decoder = MessageDecoder(self.delegate)
+        self.handlers = [FlowController(1024), self.decoder, self]
+
+    def on_start(self, drv):
+        self.driver = drv
+        self.decoder.on_start(drv)
+        self.connect()
+
+    def connect(self):
+        self.conn = self.driver.connection(self)
+        self.conn.hostname = self.address.host
+        ssn = self.conn.session()
+        rcv = ssn.receiver(str(self.address))
+        rcv.source.address = str(self.address)
+        ssn.open()
+        rcv.open()
+        self.conn.open()
+
+    def on_transport_closed(self, event):
+        conn = event.context.connection
+        self.conn = None
+        self.driver.schedule(self.connect, 1)

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/db_common.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/db_common.py b/examples/engine/py/db_common.py
new file mode 100644
index 0000000..584c15a
--- /dev/null
+++ b/examples/engine/py/db_common.py
@@ -0,0 +1,93 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+import Queue
+import sqlite3
+import threading
+
+class Db(object):
+    def __init__(self, db, events):
+        self.db = db
+        self.events = events
+        self.tasks = Queue.Queue()
+        self.position = None
+        self.pending_events = []
+        self.thread = threading.Thread(target=self._process)
+        self.thread.daemon=True
+        self.thread.start()
+
+    def reset(self):
+        self.tasks.put(lambda conn: self._reset())
+
+    def load(self, records, event=None):
+        self.tasks.put(lambda conn: self._load(conn, records, event))
+
+    def insert(self, id, data, event=None):
+        self.tasks.put(lambda conn: self._insert(conn, id, data, event))
+
+    def delete(self, id, event=None):
+        self.tasks.put(lambda conn: self._delete(conn, id, event))
+
+    def _reset(self, ignored=None):
+        self.position = None
+
+    def _load(self, conn, records, event):
+        if self.position:
+            cursor = conn.execute("SELECT * FROM records WHERE id > ? ORDER BY id", (self.position,))
+        else:
+            cursor = conn.execute("SELECT * FROM records ORDER BY id")
+        while not records.full():
+            row = cursor.fetchone()
+            if row:
+                self.position = row['id']
+                records.put(dict(row))
+            else:
+                break
+        if event:
+            self.events.trigger(event)
+
+    def _insert(self, conn, id, data, event):
+        if id:
+            conn.execute("INSERT INTO records(id, description) VALUES (?, ?)", (id, data))
+        else:
+            conn.execute("INSERT INTO records(description) VALUES (?)", (data,))
+        if event:
+            self.pending_events.append(event)
+
+    def _delete(self, conn, id, event):
+        conn.execute("DELETE FROM records WHERE id=?", (id,))
+        if event:
+            self.pending_events.append(event)
+
+    def _process(self):
+        conn = sqlite3.connect(self.db)
+        conn.row_factory = sqlite3.Row
+        with conn:
+            while True:
+                f = self.tasks.get(True)
+                try:
+                    while True:
+                        f(conn)
+                        f = self.tasks.get(False)
+                except Queue.Empty: pass
+                conn.commit()
+                for event in self.pending_events:
+                    self.events.trigger(event)
+                self.pending_events = []

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/db_ctrl.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/db_ctrl.py b/examples/engine/py/db_ctrl.py
new file mode 100755
index 0000000..b28e0eb
--- /dev/null
+++ b/examples/engine/py/db_ctrl.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+import sqlite3
+import sys
+
+if len(sys.argv) < 3:
+    print "Usage: %s [init|insert|list] db" % sys.argv[0]
+else:
+    conn = sqlite3.connect(sys.argv[2])
+    with conn:
+        if sys.argv[1] == "init":
+            conn.execute("DROP TABLE IF EXISTS records")
+            conn.execute("CREATE TABLE records(id INTEGER PRIMARY KEY AUTOINCREMENT, description TEXT)")
+            conn.commit()
+        elif sys.argv[1] == "list":
+            cursor = conn.cursor()
+            cursor.execute("SELECT * FROM records")
+            rows = cursor.fetchall()
+            for r in rows:
+                print r
+        elif sys.argv[1] == "insert":
+            while True:
+                l = sys.stdin.readline()
+                if not l: break
+                conn.execute("INSERT INTO records(description) VALUES (?)", (l.rstrip(),))
+            conn.commit()
+        else:
+            print "Unrecognised command: %s" %  sys.argv[1]

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/db_recv.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/db_recv.py b/examples/engine/py/db_recv.py
new file mode 100755
index 0000000..8b4490d
--- /dev/null
+++ b/examples/engine/py/db_recv.py
@@ -0,0 +1,54 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton.handlers import MessagingHandler
+from proton.reactors import ApplicationEvent, Container
+from db_common import Db
+
+class Recv(MessagingHandler):
+    def __init__(self, url):
+        super(Recv, self).__init__(auto_accept=False)
+        self.url = url
+        self.delay = 0
+        # TODO: load last tag from db
+        self.last_id = None
+
+    def on_start(self, event):
+        self.db = Db("dst_db", event.container.get_event_trigger())
+        event.container.create_receiver(self.url)
+
+    def on_record_inserted(self, event):
+        self.accept(event.delivery)
+
+    def on_message(self, event):
+        id = int(event.message.id)
+        if (not self.last_id) or id > self.last_id:
+            self.last_id = id
+            self.db.insert(id, event.message.body, ApplicationEvent("record_inserted", delivery=event.delivery))
+            print "inserted message %s" % id
+        else:
+            self.accept(event.delivery)
+
+try:
+    Container(Recv("localhost:5672/examples")).run()
+except KeyboardInterrupt: pass
+
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/db_send.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/db_send.py b/examples/engine/py/db_send.py
new file mode 100755
index 0000000..ce3ce79
--- /dev/null
+++ b/examples/engine/py/db_send.py
@@ -0,0 +1,85 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+import Queue
+import time
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton.reactors import ApplicationEvent, Container
+from db_common import Db
+
+class Send(MessagingHandler):
+    def __init__(self, url):
+        super(Send, self).__init__()
+        self.url = url
+        self.delay = 0
+        self.sent = 0
+        self.load_count = 0
+        self.records = Queue.Queue(maxsize=50)
+
+    def on_start(self, event):
+        self.container = event.container
+        self.db = Db("src_db", self.container.get_event_trigger())
+        self.sender = self.container.create_sender(self.url)
+
+    def on_records_loaded(self, event):
+        if self.records.empty():
+            if event.subject == self.load_count:
+                print "Exhausted available data, waiting to recheck..."
+                # check for new data after 5 seconds
+                self.container.schedule(time.time() + 5, link=self.sender, subject="data")
+        else:
+            self.send()
+
+    def request_records(self):
+        if not self.records.full():
+            print "loading records..."
+            self.load_count += 1
+            self.db.load(self.records, event=ApplicationEvent("records_loaded", link=self.sender, subject=self.load_count))
+
+    def on_credit(self, event):
+        self.send()
+
+    def send(self):
+        while self.sender.credit and not self.records.empty():
+            record = self.records.get(False)
+            id = record['id']
+            self.sender.send_msg(Message(id=id, durable=True, body=record['description']), tag=str(id))
+            self.sent += 1
+            print "sent message %s" % id
+        self.request_records()
+
+    def on_settled(self, event):
+        id = int(event.delivery.tag)
+        self.db.delete(id)
+        print "settled message %s" % id
+
+    def on_disconnected(self, event):
+        self.db.reset()
+
+    def on_timer(self, event):
+        if event.subject == "data":
+            print "Rechecking for data..."
+            self.request_records()
+
+try:
+    Container(Send("localhost:5672/examples")).run()
+except KeyboardInterrupt: pass
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/helloworld.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/helloworld.py b/examples/engine/py/helloworld.py
new file mode 100755
index 0000000..92d6083
--- /dev/null
+++ b/examples/engine/py/helloworld.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton.reactors import Container
+
+class HelloWorld(MessagingHandler):
+    def __init__(self, server, address):
+        super(HelloWorld, self).__init__()
+        self.server = server
+        self.address = address
+
+    def on_start(self, event):
+        conn = event.container.connect(self.server)
+        event.container.create_receiver(conn, self.address)
+        event.container.create_sender(conn, self.address)
+
+    def on_credit(self, event):
+        event.sender.send_msg(Message(body=u"Hello World!"))
+        event.sender.close()
+
+    def on_message(self, event):
+        print event.message.body
+        event.connection.close()
+
+Container(HelloWorld("localhost:5672", "examples")).run()
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/helloworld_blocking.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/helloworld_blocking.py b/examples/engine/py/helloworld_blocking.py
new file mode 100755
index 0000000..9c5e062
--- /dev/null
+++ b/examples/engine/py/helloworld_blocking.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.utils import BlockingConnection
+from proton.handlers import IncomingMessageHandler
+
+class HelloWorldReceiver(IncomingMessageHandler):
+    def on_message(self, event):
+        print event.message.body
+        event.connection.close()
+
+conn = BlockingConnection("localhost:5672")
+conn.create_receiver("examples", handler=HelloWorldReceiver())
+sender = conn.create_sender("examples")
+sender.send_msg(Message(body=u"Hello World!"));
+conn.run()
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/helloworld_direct.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/helloworld_direct.py b/examples/engine/py/helloworld_direct.py
new file mode 100755
index 0000000..c961fe5
--- /dev/null
+++ b/examples/engine/py/helloworld_direct.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton.reactors import Container
+
+class HelloWorld(MessagingHandler):
+    def __init__(self, url):
+        super(HelloWorld, self).__init__()
+        self.url = url
+
+    def on_start(self, event):
+        self.acceptor = event.container.listen(self.url)
+        event.container.create_sender(self.url)
+
+    def on_credit(self, event):
+        event.sender.send_msg(Message(body=u"Hello World!"))
+        event.sender.close()
+
+    def on_message(self, event):
+        print event.message.body
+
+    def on_accepted(self, event):
+        event.connection.close()
+
+    def on_connection_closed(self, event):
+        self.acceptor.close()
+
+Container(HelloWorld("localhost:8888/examples")).run()

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/helloworld_direct_tornado.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/helloworld_direct_tornado.py b/examples/engine/py/helloworld_direct_tornado.py
new file mode 100755
index 0000000..8873357
--- /dev/null
+++ b/examples/engine/py/helloworld_direct_tornado.py
@@ -0,0 +1,52 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton_tornado import TornadoLoop
+
+class HelloWorld(MessagingHandler):
+    def __init__(self, server, address):
+        super(HelloWorld, self).__init__()
+        self.server = server
+        self.address = address
+
+    def on_start(self, event):
+        self.eventloop = event.container
+        self.acceptor = event.container.listen(self.server)
+        conn = event.container.connect(self.server)
+        event.container.create_sender(conn, self.address)
+
+    def on_credit(self, event):
+        event.sender.send_msg(Message(body=u"Hello World!"))
+        event.sender.close()
+
+    def on_message(self, event):
+        print event.message.body
+
+    def on_accepted(self, event):
+        event.connection.close()
+
+    def on_connection_closed(self, event):
+        self.acceptor.close()
+        self.eventloop.stop()
+
+TornadoLoop(HelloWorld("localhost:8888", "examples")).run()
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/helloworld_tornado.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/helloworld_tornado.py b/examples/engine/py/helloworld_tornado.py
new file mode 100755
index 0000000..f7d4c26
--- /dev/null
+++ b/examples/engine/py/helloworld_tornado.py
@@ -0,0 +1,49 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton_tornado import TornadoLoop
+
+class HelloWorld(MessagingHandler):
+    def __init__(self, server, address):
+        super(HelloWorld, self).__init__()
+        self.server = server
+        self.address = address
+
+    def on_start(self, event):
+        self.eventloop = event.container
+        conn = event.container.connect(self.server)
+        event.container.create_receiver(conn, self.address)
+        event.container.create_sender(conn, self.address)
+
+    def on_credit(self, event):
+        event.sender.send_msg(Message(body=u"Hello World!"))
+        event.sender.close()
+
+    def on_message(self, event):
+        print event.message.body
+        event.connection.close()
+
+    def on_connection_closed(self, event):
+        self.eventloop.stop()
+
+TornadoLoop(HelloWorld("localhost:5672", "examples")).run()
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/proton_server.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/proton_server.py b/examples/engine/py/proton_server.py
new file mode 100644
index 0000000..8a5077b
--- /dev/null
+++ b/examples/engine/py/proton_server.py
@@ -0,0 +1,61 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.reactors import Container
+from proton.handlers import MessagingHandler
+
+class Server(MessagingHandler):
+    def __init__(self, host, address):
+        super(Server, self).__init__()
+        self.container = Container(self)
+        self.conn = self.container.connect(host)
+        self.receiver = self.container.create_receiver(self.conn, address)
+        self.senders = {}
+        self.relay = None
+
+    def on_message(self, event):
+        self.on_request(event.message.body, event.message.reply_to)
+
+    def on_connection_open(self, event):
+        if event.connection.remote_offered_capabilities and "ANONYMOUS-RELAY" in event.connection.remote_offered_capabilities:
+            self.relay = self.container.create_sender(self.conn, None)
+
+    def on_connection_close(self, endpoint, error):
+        if error: print "Closed due to %s" % error
+        self.conn.close()
+
+    def run(self):
+        self.container.run()
+
+    def send(self, response, reply_to):
+        sender = self.relay
+        if not sender:
+            sender = self.senders.get(reply_to)
+        if not sender:
+            sender = self.container.create_sender(self.conn, reply_to)
+            self.senders[reply_to] = sender
+        msg = Message(body=response)
+        if self.relay:
+            msg.address = reply_to
+        sender.send_msg(msg)
+
+    def on_request(self, request, reply_to):
+        pass
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/proton_tornado.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/proton_tornado.py b/examples/engine/py/proton_tornado.py
new file mode 100644
index 0000000..cfe7d6f
--- /dev/null
+++ b/examples/engine/py/proton_tornado.py
@@ -0,0 +1,70 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton.reactors import ApplicationEvent, Container, StartEvent
+import tornado.ioloop
+
+class TornadoLoop(Container):
+    def __init__(self, *handlers):
+        super(TornadoLoop, self).__init__(*handlers)
+        self.loop = tornado.ioloop.IOLoop.current()
+
+    def connect(self, url=None, urls=None, address=None, handler=None, reconnect=None):
+        conn = super(TornadoLoop, self).connect(url, urls, address, handler, reconnect)
+        self.events.process()
+        return conn
+
+    def schedule(self, deadline, connection=None, session=None, link=None, delivery=None, subject=None):
+        self.loop.call_at(deadline, self.events.dispatch, ApplicationEvent("timer", connection, session, link, delivery, subject))
+
+    def add(self, conn):
+        self.loop.add_handler(conn, self._connection_ready, tornado.ioloop.IOLoop.READ | tornado.ioloop.IOLoop.WRITE)
+
+    def remove(self, conn):
+        self.loop.remove_handler(conn)
+
+    def run(self):
+        self.events.dispatch(StartEvent(self))
+        self.loop.start()
+
+    def stop(self):
+        self.loop.stop()
+
+    def _get_event_flags(self, conn):
+        flags = 0
+        if conn.reading():
+            flags |= tornado.ioloop.IOLoop.READ
+        # FIXME: need way to update flags to avoid busy loop
+        #if conn.writing():
+        #    flags |= tornado.ioloop.IOLoop.WRITE
+        flags |= tornado.ioloop.IOLoop.WRITE
+        return flags
+
+    def _connection_ready(self, conn, events):
+        if events & tornado.ioloop.IOLoop.READ:
+            conn.readable()
+        if events & tornado.ioloop.IOLoop.WRITE:
+            conn.writable()
+        if events & tornado.ioloop.IOLoop.ERROR:# or conn.closed():
+            self.loop.remove_handler(conn)
+            conn.close()
+            conn.removed()
+        self.events.process()
+        self.loop.update_handler(conn, self._get_event_flags(conn))

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/recurring_timer.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/recurring_timer.py b/examples/engine/py/recurring_timer.py
new file mode 100755
index 0000000..de530d3
--- /dev/null
+++ b/examples/engine/py/recurring_timer.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+import time
+from proton.reactors import Container, Handler
+
+class Recurring(Handler):
+    def __init__(self, period):
+        self.period = period
+
+    def on_start(self, event):
+        self.container = event.container
+        self.container.schedule(time.time() + self.period, subject=self)
+
+    def on_timer(self, event):
+        print "Tick..."
+        self.container.schedule(time.time() + self.period, subject=self)
+
+try:
+    container = Container(Recurring(1.0))
+    container.run()
+except KeyboardInterrupt:
+    container.stop()
+    print
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/recurring_timer_tornado.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/recurring_timer_tornado.py b/examples/engine/py/recurring_timer_tornado.py
new file mode 100755
index 0000000..aeeb20c
--- /dev/null
+++ b/examples/engine/py/recurring_timer_tornado.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+import time
+from proton.reactors import Handler
+from proton_tornado import TornadoLoop
+
+class Recurring(Handler):
+    def __init__(self, period):
+        self.period = period
+
+    def on_start(self, event):
+        self.container = event.container
+        self.container.schedule(time.time() + self.period, subject=self)
+
+    def on_timer(self, event):
+        print "Tick..."
+        self.container.schedule(time.time() + self.period, subject=self)
+
+try:
+    container = TornadoLoop(Recurring(1.0))
+    container.run()
+except KeyboardInterrupt:
+    container.stop()
+    print
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/selected_recv.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/selected_recv.py b/examples/engine/py/selected_recv.py
new file mode 100755
index 0000000..d0df3b5
--- /dev/null
+++ b/examples/engine/py/selected_recv.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton.reactors import Container, Selector
+from proton.handlers import MessagingHandler
+
+class Recv(MessagingHandler):
+    def __init__(self):
+        super(Recv, self).__init__()
+
+    def on_start(self, event):
+        conn = event.container.connect("localhost:5672")
+        event.container.create_receiver(conn, "examples", options=Selector(u"colour = 'green'"))
+
+    def on_message(self, event):
+        print event.message.body
+
+try:
+    Container(Recv()).run()
+except KeyboardInterrupt: pass
+
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/server.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/server.py b/examples/engine/py/server.py
new file mode 100755
index 0000000..3e6aad4
--- /dev/null
+++ b/examples/engine/py/server.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton.reactors import Container
+
+class Server(MessagingHandler):
+    def __init__(self, host, address):
+        super(Server, self).__init__()
+        self.host = host
+        self.address = address
+
+    def on_start(self, event):
+        self.container = event.container
+        self.conn = event.container.connect(self.host)
+        self.receiver = event.container.create_receiver(self.conn, self.address)
+        self.senders = {}
+        self.relay = None
+
+    def on_connection_opened(self, event):
+        if event.connection.remote_offered_capabilities and 'ANONYMOUS-RELAY' in event.connection.remote_offered_capabilities:
+            self.relay = self.container.create_sender(self.conn, None)
+
+    def on_message(self, event):
+        sender = self.relay
+        if not sender:
+            sender = self.senders.get(event.message.reply_to)
+        if not sender:
+            sender = self.container.create_sender(self.conn, event.message.reply_to)
+            self.senders[event.message.reply_to] = sender
+        sender.send_msg(Message(address=event.message.reply_to, body=event.message.body.upper()))
+
+try:
+    Container(Server("localhost:5672", "examples")).run()
+except KeyboardInterrupt: pass
+
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/server_tx.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/server_tx.py b/examples/engine/py/server_tx.py
new file mode 100755
index 0000000..0305a3f
--- /dev/null
+++ b/examples/engine/py/server_tx.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.reactors import Container
+from proton.handlers import MessagingHandler, TransactionHandler
+
+class TxRequest(TransactionHandler):
+    def __init__(self, response, sender, request_delivery):
+        super(TxRequest, self).__init__()
+        self.response = response
+        self.sender = sender
+        self.request_delivery = request_delivery
+
+    def on_transaction_declared(self, event):
+        self.sender.send_msg(self.response, transaction=event.transaction)
+        self.accept(self.request_delivery, transaction=event.transaction)
+        event.transaction.commit()
+
+    def on_transaction_committed(self, event):
+        print "Request processed successfully"
+
+    def on_transaction_aborted(self, event):
+        print "Request processing aborted"
+
+
+class TxServer(MessagingHandler):
+    def __init__(self, host, address):
+        super(TxServer, self).__init__(auto_accept=False)
+        self.host = host
+        self.address = address
+
+    def on_start(self, event):
+        self.container = event.container
+        self.conn = event.container.connect(self.host, reconnect=False)
+        self.receiver = event.container.create_receiver(self.conn, self.address)
+        self.senders = {}
+        self.relay = None
+
+    def on_message(self, event):
+        sender = self.relay
+        if not sender:
+            sender = self.senders.get(event.message.reply_to)
+        if not sender:
+            sender = self.container.create_sender(self.conn, event.message.reply_to)
+            self.senders[event.message.reply_to] = sender
+
+        response = Message(address=event.message.reply_to, body=event.message.body.upper())
+        self.container.declare_transaction(self.conn, handler=TxRequest(response, sender, event.delivery))
+
+    def on_connection_open(self, event):
+        if event.connection.remote_offered_capabilities and 'ANONYMOUS-RELAY' in event.connection.remote_offered_capabilities:
+            self.relay = self.container.create_sender(self.conn, None)
+
+try:
+    Container(TxServer("localhost:5672", "examples")).run()
+except KeyboardInterrupt: pass
+
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/simple_recv.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/simple_recv.py b/examples/engine/py/simple_recv.py
new file mode 100755
index 0000000..6825c86
--- /dev/null
+++ b/examples/engine/py/simple_recv.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton.handlers import MessagingHandler
+from proton.reactors import Container
+
+class Recv(MessagingHandler):
+    def __init__(self, url):
+        super(Recv, self).__init__()
+        self.url = url
+
+    def on_start(self, event):
+        event.container.create_receiver(self.url)
+
+    def on_message(self, event):
+        print event.message.body
+
+try:
+    Container(Recv("localhost:5672/examples")).run()
+except KeyboardInterrupt: pass
+
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/simple_send.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/simple_send.py b/examples/engine/py/simple_send.py
new file mode 100755
index 0000000..21530ef
--- /dev/null
+++ b/examples/engine/py/simple_send.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton import Message
+from proton.handlers import MessagingHandler
+from proton.reactors import Container
+
+class Send(MessagingHandler):
+    def __init__(self, url, messages):
+        super(Send, self).__init__()
+        self.url = url
+        self.sent = 0
+        self.confirmed = 0
+        self.total = messages
+
+    def on_start(self, event):
+        event.container.create_sender(self.url)
+
+    def on_credit(self, event):
+        while event.sender.credit and self.sent < self.total:
+            msg = Message(body={'sequence':(self.sent+1)})
+            event.sender.send_msg(msg)
+            self.sent += 1
+
+    def on_accepted(self, event):
+        self.confirmed += 1
+        if self.confirmed == self.total:
+            print "all messages confirmed"
+            event.connection.close()
+
+    def on_disconnected(self, event):
+        self.sent = self.confirmed
+
+try:
+    Container(Send("localhost:5672/examples", 10000)).run()
+except KeyboardInterrupt: pass

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/sync_client.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/sync_client.py b/examples/engine/py/sync_client.py
new file mode 100755
index 0000000..362385a
--- /dev/null
+++ b/examples/engine/py/sync_client.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+"""
+Demonstrates the client side of the synchronous request-response pattern
+(also known as RPC or Remote Procecure Call) using proton.
+
+"""
+
+from proton import Message, Url, ConnectionException, Timeout
+from proton.utils import BlockingConnection
+from proton.handlers import IncomingMessageHandler
+import sys
+
+class SyncRequestClient(IncomingMessageHandler):
+    """
+    Implementation of the synchronous request-responce (aka RPC) pattern.
+    Create an instance and call invoke() to send a request and wait for a response.
+    """
+
+    def __init__(self, url, timeout=None):
+        """
+        @param url: a proton.Url or a URL string of the form 'host:port/path'
+            host:port is used to connect, path is used to identify the remote messaging endpoint.
+        """
+        super(SyncRequestClient, self).__init__()
+        self.connection = BlockingConnection(Url(url).defaults(), timeout=timeout)
+        self.sender = self.connection.create_sender(url.path)
+        # dynamic=true generates a unique address dynamically for this receiver.
+        # credit=1 because we want to receive 1 response message initially.
+        self.receiver = self.connection.create_receiver(None, dynamic=True, credit=1, handler=self)
+        self.response = None
+
+    def invoke(self, request):
+        """Send a request, wait for and return the response"""
+        request.reply_to = self.reply_to
+        self.sender.send_msg(request)
+        self.connection.wait(lambda: self.response, msg="Waiting for response")
+        response = self.response
+        self.response = None    # Ready for next response.
+        self.receiver.flow(1)   # Set up credit for the next response.
+        return response
+
+    @property
+    def reply_to(self):
+        """Return the dynamic address of our receiver."""
+        return self.receiver.remote_source.address
+
+    def on_message(self, event):
+        """Called when we receive a message for our receiver."""
+        self.response = event.message # Store the response
+
+    def close(self):
+        self.connection.close()
+
+
+if __name__ == '__main__':
+    url = Url("0.0.0.0/examples")
+    if len(sys.argv) > 1: url = Url(sys.argv[1])
+
+    invoker = SyncRequestClient(url, timeout=2)
+    try:
+        REQUESTS= ["Twas brillig, and the slithy toves",
+                   "Did gire and gymble in the wabe.",
+                   "All mimsy were the borogroves,",
+                   "And the mome raths outgrabe."]
+        for request in REQUESTS:
+            response = invoker.invoke(Message(body=request))
+            print "%s => %s" % (request, response.body)
+    finally:
+        invoker.close()

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/tx_recv.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/tx_recv.py b/examples/engine/py/tx_recv.py
new file mode 100755
index 0000000..fc4bb8a
--- /dev/null
+++ b/examples/engine/py/tx_recv.py
@@ -0,0 +1,61 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+from proton.reactors import Container
+from proton.handlers import TransactionalClientHandler
+
+class TxRecv(TransactionalClientHandler):
+    def __init__(self, batch_size):
+        super(TxRecv, self).__init__(prefetch=0)
+        self.current_batch = 0
+        self.batch_size = batch_size
+
+    def on_start(self, event):
+        self.container = event.container
+        self.conn = self.container.connect("localhost:5672")
+        self.receiver = self.container.create_receiver(self.conn, "examples")
+        self.container.declare_transaction(self.conn, handler=self)
+        self.transaction = None
+
+    def on_message(self, event):
+        print event.message.body
+        self.accept(event.delivery, self.transaction)
+        self.current_batch += 1
+        if self.current_batch == self.batch_size:
+            self.transaction.commit()
+            self.transaction = None
+
+    def on_transaction_declared(self, event):
+        self.receiver.flow(self.batch_size)
+        self.transaction = event.transaction
+
+    def on_transaction_committed(self, event):
+        self.current_batch = 0
+        self.container.declare_transaction(self.conn, handler=self)
+
+    def on_disconnected(self, event):
+        self.current_batch = 0
+
+try:
+    Container(TxRecv(10)).run()
+except KeyboardInterrupt: pass
+
+
+

http://git-wip-us.apache.org/repos/asf/qpid-proton/blob/34e64e32/examples/engine/py/tx_recv_interactive.py
----------------------------------------------------------------------
diff --git a/examples/engine/py/tx_recv_interactive.py b/examples/engine/py/tx_recv_interactive.py
new file mode 100755
index 0000000..6eb320e
--- /dev/null
+++ b/examples/engine/py/tx_recv_interactive.py
@@ -0,0 +1,83 @@
+#!/usr/bin/env python
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+import sys
+import threading
+from proton.reactors import ApplicationEvent, Container
+from proton.handlers import TransactionalClientHandler
+
+class TxRecv(TransactionalClientHandler):
+    def __init__(self):
+        super(TxRecv, self).__init__(prefetch=0)
+
+    def on_start(self, event):
+        self.container = event.container
+        self.conn = self.container.connect("localhost:5672")
+        self.receiver = self.container.create_receiver(self.conn, "examples")
+        self.container.declare_transaction(self.conn, handler=self, settle_before_discharge=True)
+        self.transaction = None
+
+    def on_message(self, event):
+        print event.message.body
+        self.transaction.accept(event.delivery)
+
+    def on_transaction_declared(self, event):
+        self.transaction = event.transaction
+        print "transaction declared"
+
+    def on_transaction_committed(self, event):
+        print "transaction committed"
+        self.container.declare_transaction(self.conn, handler=self)
+
+    def on_transaction_aborted(self, event):
+        print "transaction aborted"
+        self.container.declare_transaction(self.conn, handler=self)
+
+    def on_commit(self, event):
+        self.transaction.commit()
+
+    def on_abort(self, event):
+        self.transaction.abort()
+
+    def on_fetch(self, event):
+        self.receiver.flow(1)
+
+    def on_quit(self, event):
+        c = self.receiver.connection
+        self.receiver.close()
+        c.close()
+
+try:
+    reactor = Container(TxRecv())
+    events = reactor.get_event_trigger()
+    thread = threading.Thread(target=reactor.run)
+    thread.daemon=True
+    thread.start()
+
+    print "Enter 'fetch', 'commit' or 'abort'"
+    while True:
+        line = sys.stdin.readline()
+        if line:
+            events.trigger(ApplicationEvent(line.strip()))
+        else:
+            break
+except KeyboardInterrupt: pass
+
+


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