Package: eventsource
README: Event Source Library for Python=======================================This library implements W3C Draft's on event-source:- http://dev.w3.org/html5/eventsource/It enables a halfduplex communication from server to client, but initiatedby the client, through standard HTTP(S) communication.Dependances------------ Fairly recent python (tested with 2.7)- Fairly recent tornado (tested with 2.2.1)Usage-----1. Launch the server:eventsource_listener -P 8888 -i -k 500002. Launch the client:eventsource_client 42:42:42:42:42:42 -r 50003. Send requests:eventsource_request 42:42:42:42:42:42 ping "42"eventsource_request 42:42:42:42:42:42 closeCommand Line arguments----------------------- `eventsource/listener.py` or `eventsource_server`:usage: eventsource/listener.py [-h] [-H HOST] [-P PORT] [-d][-j] [-k KEEPALIVE] [-i]Event Source Listeneroptional arguments:-h, --help            show this help message and exit-H HOST, --host HOST  Host to bind on-P PORT, --port PORT  Port to bind on-d, --debug           enables debug output-j, --json            to enable JSON Event-k KEEPALIVE, --keepalive KEEPALIVEKeepalive timeout-i, --id              to generate identifiers- `eventsource/client.py` or `eventsource_client`:usage: eventsource/client.py [-h] [-H HOST] [-P PORT] [-d][-r RETRY]tokenEvent Source Clientpositional arguments:token                 Token to be used for connectionoptional arguments:-h, --help            show this help message and exit-H HOST, --host HOST  Host to connect to-P PORT, --port PORT  Port to be used connection-d, --debug           enables debug output-r RETRY, --retry RETRYReconnection timeout- `eventsource/send_request.py` or `eventsource_request`:usage: eventsource/send_request.py [-h] [-H HOST] [-P PORT] [-j]token action [data]Generates event for Event Source Librarypositional arguments:token                 Token to be used for connectionaction                Action to senddata                  Data to be sentoptional arguments:-h, --help            show this help message and exit-H HOST, --host HOST  Host to connect to-P PORT, --port PORT  Port to be used connection-j, --json            Treat data as JSONIntegrate---------On the server side, basically all you have to do is to add the following to your code:from eventsource import listenerapplication = tornado.web.Application([(r"/(.*)/(.*)", listener.EventSourceHandler,dict(event_class=EVENT,keepalive=KEEPALIVE)),])application.listen(PORT)tornado.ioloop.IOLoop.instance().start()where:- PORT is an integer for the port to bind to- KEEPALIVE is an integer for the timeout between two keepalive messages (to protect from disconnections)- EVENT is a eventsource.listener.Event based class, either one you made or- eventsource.listener.StringEvent : Each event gets and resends multiline strings- eventsource.listener.StringIdEvent : Each event gets and resends multiline strings, with an unique id for each event- eventsource.listener.JSONEvent : Each event gets and resends JSON valid strings- eventsource.listener.JSONIdEvent : Each event gets and resends JSON valid string, with an unique id for each eventExtend------To extend the behaviour of the event source library, without breaking eventsourcedefinition, the Event based classes implements all processing elements that shallbe done on events.There is two abstract classes that defines Event:- eventsource.listener.Event : defines the constructor of an Event- eventsource.listener.EventId : defines an always incrementing id handlerhere is an example to create a new Event that takes multiline data and join it in a oneline string seperated with semi-colons.class OneLineEvent(Event):ACTIONS = ["ping",Event.FINISH]"""Property to enable multiline output of the value"""def get_value(self):# replace carriage returns by semi-colons# this method shall always return a list (even if one value)return [";".join([line for line in self._value.split('\n')])]value = property(get_value,set_value)And now, I want to add basic id support to OneLineEvent, in OneLineIdEvent,nothing is easier :class OneLineIdEvent(OneLineEvent,IdEvent):id = property(IdEvent.get_value)Or if I want the id to be a timestamp:import timeclass OneLineTimeStampEvent(OneLineEvent):id = property(lambda s: "%f" % (time.time(),))You can change the behaviour of a few things in a Event-based class:- Event.LISTEN contains the GET action to open a connection (per default "poll")- Event.FINISH contains the POST action to close a connection (per default "close")- Event.RETRY contains the POST action to define the timeout after reconnecting on network disconnection (per default "0", which means disabled)- in the Event.ACTIONS list, you define what POST actions are allowed, per default,  only Event.FINISH is allowed.- Event.content_type contains the "content_type" that will be asked for every form (it is not enforced).To change the way events are generated, you can directly call EventSourceHandler.buffer_event()to create a new event to be sent. But the post action is best, at least while WSGI can't handlecorrectly long polling connections.Licensing---------Python Event Source Library(c) 2012 Bernard PratzPatches by Ian Whyman and Коренберг МаркThis program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3 of the License.This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.EOFSee http://packages.python.org/eventsource/ for the full documentationSee https://github.com/guyzmo/event-source-library for latest sources and for patchesNews====version 1.1.0:* syntax clean up* in listener:* removed events buffering as a deque* added toro dependency* added toro.asyncresult to replace event's deque buffer* used toro.asyncresult to block and call the event loop* in client:* added keep alive parameterversion 1.0.5:* moved event_loop callback rearming away* changed events buffer from list to dequeversion 1.0.4:* added invalid SSL certificates support* integrated patches from Ian Whyman:* support of bad HTTP services implementations (be compatible with '\n' and '\r\n')* added user/password support for connections in client* integrated patches from Коренберг Марк:* use of json module of tornado* cosmetic changesversion 1.0.3:* added support for SSL connections