pushlet基本流程

最新推荐文章于 2017-06-07 15:51:35 发布

anghlq

最新推荐文章于 2017-06-07 15:51:35 发布

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分类专栏： WEB编程程序设计文章标签： loops command stream events join caching

本文链接：https://blog.youkuaiyun.com/anghlq/article/details/5869233

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长链接：

客户端长轮询(pull,poll)

Stream, （在Subscriber.fetchEvents{ while (isActive()){deQueueAll()；//没有命令就发心跳}}）

流程：

Pushlet.doRequest

1. 创建会话

2. Controller.doCommand

public void doCommand(Command aCommand) { try { // Update lease time to live session.kick(); // Set remote IP address of client session.setAddress(aCommand.httpReq.getRemoteAddr()); debug("doCommand() event=" + aCommand.reqEvent); // Get event type String eventType = aCommand.reqEvent.getEventType(); // Determine action based on event type if (eventType.equals(Protocol.E_REFRESH)) { // Pull/poll mode clients that refresh doRefresh(aCommand); } else if (eventType.equals(Protocol.E_SUBSCRIBE)) { // Subscribe doSubscribe(aCommand); } else if (eventType.equals(Protocol.E_UNSUBSCRIBE)) { // Unsubscribe doUnsubscribe(aCommand); } else if (eventType.equals(Protocol.E_JOIN)) { // Join doJoin(aCommand); } else if (eventType.equals(Protocol.E_JOIN_LISTEN)) { // Join and listen (for simple and e.g. REST apps) doJoinListen(aCommand); } else if (eventType.equals(Protocol.E_LEAVE)) { // Leave doLeave(aCommand); } else if (eventType.equals(Protocol.E_HEARTBEAT)) { // Heartbeat mainly to do away with browser "busy" cursor doHeartbeat(aCommand); } else if (eventType.equals(Protocol.E_PUBLISH)) { // Publish event doPublish(aCommand); } else if (eventType.equals(Protocol.E_LISTEN)) { // Listen to pushed events doListen(aCommand); } // Handle response back to client if (eventType.endsWith(Protocol.E_LISTEN) || eventType.equals(Protocol.E_REFRESH)) { // Data channel events // Loops until refresh or connection closed getSubscriber().fetchEvents(aCommand); } else { // Send response for control commands sendControlResponse(aCommand); } } catch (Throwable t) { warn("Exception in doCommand(): " + t); t.printStackTrace(); } }

{

//根据客户端的命令进行命令分发

启动或停止subscriber,设置返回的命令等，若是publish事件-->

Dispatcher.getInstance().unicast(aCommand.reqEvent, to); || Dispatcher.getInstance().multicast(aCommand.reqEvent);

//分发完毕执行，Handle response back to client

                if (eventType.endsWith(Protocol.E_LISTEN) ||
                    eventType.equals(Protocol.E_REFRESH)) {
                    // Data channel events
                    // Loops until refresh or connection closed
                     getSubscriber().fetchEvents(aCommand);

                 } else {
                     // Send response for control commands
                       sendControlResponse(aCommand);
                 }

}

入库

Dispatcher.getInstance().multicast-->

multicast或unicast触发

SessionManager.getInstance().apply(sessionManagerVisitor, method, args);

遍历所有的会话，进行调用

visitMulticast || visitBroadcast

判断当前会话的Subscriber是否符合条件，符合就调用-->

Subscriber.onEvent(e){enQueue()}

SessionManager对event进行管理（AgingTimerTask），超时会话将被stop()，会话也会stop从属于它的Subscriber;

出库

长轮询是sendControlResponse(aCommand);

protected void sendControlResponse(Command aCommand) {
        try {

            // Try to prevent caching in any form.
            aCommand.sendResponseHeaders();

            // Let clientAdapter determine how to send event
            aCommand.getClientAdapter().start();

            // Push to client through client adapter
            aCommand.getClientAdapter().push(aCommand.getResponseEvent());

            // One shot response
            aCommand.getClientAdapter().stop();
        } catch (Throwable t) {
            session.stop();
        }
    }