原文链接：http://blog.miguelgrinberg.com/post/easy-websockets-with-flask-and-gevent
介绍部分就先不翻了
This weekend I decided to take a short vacation from my book writing effort and spend time on a project I wanted to work on for a long time. The result of this effort is a brand new Flask extension that I think is pretty cool.
I'm happy to introduce Flask-SocketIO, a very easy to use extension that enables WebSocket communications in Flask applications.
What is WebSocket?
WebSocket is a new communication protocol introduced with HTML5, mainly to be implemented by web clients and servers, though it can also be implemented outside of the web.
Unlike HTTP connections, a WebSocket connection is a permanent, bi-directional communication channel between a client and the server, where either one can initiate an exchange. Once established, the connection remains available until one of the parties disconnects from it.
WebSocket connections are useful for games or web sites that need to display live information with very low latency. Before this protocol existed there were other much less efficient approaches to achieve the same result such as Comet.
The following web browsers support the WebSocket protocol:
- Chrome 14
- Safari 6
- Firefox 6
- Internet Explorer 10
What is SocketIO?
SocketIO is a cross-browser java script library that abstracts the client application from the actual transport protocol. For modern browsers the WebSocket protocol is used, but for older browsers that don't have WebSocket SocketIO emulates the connection using one of the older solutions, the best one available for each given client.
The important fact is that in all cases the application uses the same interface, the different transport mechanisms are abstracted behind a common API, so using SocketIO you can be pretty much sure that any browser out there will be able to connect to your application, and that for every browser the most efficient method available will be used.
What about Flask-Sockets?
A while ago Kenneth Reitz published Flask-Sockets, another extension for Flask that makes the use of WebSocket accessible to Flask applications.
The main difference between Flask-Sockets and Flask-SocketIO is that the former wraps the native WebSocket protocol (through the use of the gevent-websocket project), so it can only be used by the most modern browsers that have native support. Flask-SocketIO transparently downgrades itself for older browsers.
Another difference is that Flask-SocketIO implements the message passing protocol exposed by the SocketIO java script library. Flask-Sockets just implements the communication channel, what is sent on it is entirely up to the application.
Flask-SocketIO also creates an environment for event handlers that is close to that of regular view functions, including the creation of application and request contexts. There are some important exceptions to this explained in the documentation, however.
A Flask-SocketIO Server
Flask-SocketIO 服务器端代码
Installation of Flask-SocketIO is very simple:
使用pip安装Flask-SocketIO
$ pip install flask-socketio
Note that Flask-SocketIO depends on gevent, so at this time it can only run on Python 2.x. Support for Python 3 is coming for gevent, so the situation is likely to improve in the near future. (Update: Flask-SocketIO version 1.0 is fully compatible with Python 2.7 and 3.3+, see bottom of the article for more information).
目前的最新状态是，Flask-SocketIO版本v