Implement server push in flask framework

Implement server push in flask framework

• 1.
  Implement Server Push in Chi-Chia Huang (黃啟嘉) Oct 24 2014
• 2.
  Flask is amicroframework for Python based on Werkzeug, Jinja 2
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  Notification from server 3
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  client Server 4
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  client Server 5
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  Server Push Approaches • Polling • Long Polling • Server Sent Events • Websocket http://mrjoes.github.io/2013/06/21/python-realtime.html 6
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  Time Server/Client polling,long polling, server sent events, websocket 7
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  Polling Noise tosignal ration is usually very high… 8 Client
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  Long Polling 9 Client
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  Long Polling 10 Server use POST to prevent the browser from cache the request
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  Server Sent Events Client 11
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  Server Sent Events 12 Server The event stream is a simple stream of text data, which must be encoded using UTF-8. Each message is separated by a pair of newline characters. https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events#Event_stream_format
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  Event Stream Example https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events#Event_stream_format 13
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  14
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  Websocket[RFC6445] Client 15
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  Websocket[RFC6445] 16 Server
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  Which one isbetter? 17 • Server-Sent Events • Are sent over traditional HTTP • Automatic reconnection • Ability to send arbitrary events • WebSockets • Bi-directional, full-duplex communication
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  Chatroom Example •Polling approach: • http://chichia.aws.prd.demodesu.com:5002/type/polling • Long Polling approach: • http://chichia.aws.prd.demodesu.com:5002/type/lpolling • Server Sent Event approach: • http://chichia.aws.prd.demodesu.com:5002/type/sse • Websocket approach: • http://chichia.aws.prd.demodesu.com:5002/type/ws 18
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  Intern Training Project • http://chichia.aws.prd.demodesu.com:8080/ 19
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  References • LongPolling • Jonathan Eunice lpoll • AlanYang gevent-flask-comet • Websocket • Jonathan Eunice flask-ws-example • Server Sent Event • Oskar Blom Realtime Server Using The SSE Protocol • Eric Bidelman Stream Updates with Server-Sent Events • MDN Using Server Sent Event
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