长连接网关技术专题(四)：爱奇艺WebSocket实时推送网关技术实践

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文由爱奇艺技术团队原创分享，原题《构建通用WebSocket推送网关的设计与实践》，有优化和改动。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"1、引言","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"丛所周之，HTTP协议是一种无状态、基于TCP的请求/响应模式的协议，即请求只能由客户端发起、由服务端进行响应。在大多数场景，这种请求/响应的Pull模式可以满足需求。但在某些情形：例如消息推送（IM中最为常见，比如IM的离线消息推送）、实时通知等应用场景，需要实时将数据同步到客户端，这就要求服务端支持主动Push数据的能力。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"传统的Web服务端推送技术历史悠久，经历了短轮询、长轮询等阶段的发展（见《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-338-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"新手入门贴：史上最全Web端即时通讯技术原理详解","attrs":{}}]},{"type":"text","text":"》），一定程度上能够解决问题，但也存在着不足，例如时效性、资源浪费等。HTML5标准带来的WebSocket规范基本结束了这一局面，成为目前服务端消息推送技术的主流方案。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在系统中集成WebSocket十分简单，相关讨论与资料很丰富。但如何实现一个通用的WebSocket推送网关尚未有成熟的方案。目前的云服务厂商主要关注iOS和安卓等移动端推送，也缺少对WebSocket的支持。本文分享了爱奇艺基于Netty实现WebSocket长连接实时推送网关时的实践经验总结。","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/0f/0f781672bdab9743e8f16d6a8b7ddcbe.png","alt":"","title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"学习交流：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"- 移动端IM开发入门文章：《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-464-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"新手入门一篇就够：从零开发移动端IM","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"- 开源IM框架源码：","attrs":{}},{"type":"link","attrs":{"href":"https://github.com/JackJiang2011/MobileIMSDK","title":null,"type":null},"content":[{"type":"text","text":"https://github.com/JackJiang2011/MobileIMSDK","attrs":{}}]}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"（本文同步发布于：","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3539-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"http://www.52im.net/thread-3539-1-1.html","attrs":{}}]},{"type":"text","text":"）","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"2、专题目录","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"本文是系列文章的第4篇，总目录如下：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-1243-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"长连接网关技术专题(一)：京东京麦的生产级TCP网关技术实践总结","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-2737-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"长连接网关技术专题(二)：知乎千万级并发的高性能长连接网关技术实践","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3110-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"长连接网关技术专题(三)：手淘亿级移动端接入层网关的技术演进之路","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3539-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"长连接网关技术专题(四)：爱奇艺WebSocket实时推送网关技术实践","attrs":{}}]},{"type":"text","text":"》（* 本文）","attrs":{}}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"其它相关技术文章：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-166-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"绝对干货：基于Netty实现海量接入的推送服务技术要点","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-1548-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"京东到家基于Netty的WebSocket应用实践分享","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"爱奇艺技术团队分享的其它文章：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3028-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"爱奇艺技术分享：轻松诙谐，讲解视频编解码技术的过去、现在和将来","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-2221-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"爱奇艺技术分享：爱奇艺Android客户端启动速度优化实践总结","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-2981-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"爱奇艺移动端网络优化实践分享：网络请求成功率优化篇","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]}],"attrs":{}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"3、旧方案存在的技术痛点","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"爱奇艺号是我们内容生态的重要组成，作为前台系统，对用户体验有较高要求，直接影响着创作者的创作热情。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"目前，爱奇艺号多个业务场景中用到了WebSocket实时推送技术，包括：","attrs":{}}]},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"1）用户评论：实时的将评论消息推送到浏览器；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"2）实名认证：合同签署前需要对用户进行实名认证，用户扫描二维码后进入第三方的认证页面，认证完成后异步通知浏览器认证的状态；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"3）活体识别：类似实名认证，当活体识别完成后，异步将结果通知浏览器。","attrs":{}}]}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在实际的业务开发中，我们发现，WebSocket实时推送技术在使用中存在一些问题。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"这些问题是：","attrs":{}}]},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"1）首先：WebSocket技术栈不统一，既有基于Netty实现的，也有基于Web容器实现的，给开发和维护带来困难；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"2）其次：WebSocket实现分散在在各个工程中，与业务系统强耦合，如果有其他业务需要集成WebSocket，面临着重复开发的窘境，浪费成本、效率低下；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"3）第三：WebSocket是有状态协议的，客户端连接服务器时只和集群中一个节点连接，数据传输过程中也只与这一节点通信。WebSocket集群需要解决会话共享的问题。如果只采用单节点部署，虽然可以避免这一问题，但无法水平扩展支撑更高负载，有单点的风险；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"4）最后：缺乏监控与报警，虽然可以通过Linux的Socket连接数大致评估WebSocket长连接数，但数字并不准确，也无法得知用户数等具有业务含义的指标数据；无法与现有的微服务监控整合，实现统一监控和报警。","attrs":{}}]}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"alig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