ActiveMQ(AMQ)单浏览器AJAX多页面客户端的支持(clientId)
最近同事在使用AMQ进行消息通信时遇到了问题:在IE8中多个页面上访问AMQ的一个主题订阅的时候,多个页面中获得的消息其实是来自于同一个主题队列,导致页面状态逻辑错误.
查找AMQ的官方文档后得知,在5.4.2之后的版本中,AMQ的AJAX客户端可以通过指定唯一的clientId,让多个页面在一个浏览器中能够访问相同订阅的不同队列,避免了之前版本中只判断JSESSIONID导致的客户端无法区分的问题.官方文档在这里:
http://activemq.apache.org/ajax.html 但这里面实现的amq.js由于改动过大,无法与之前的接口兼容,所以并没有合并到官方主干源码中,只是以demo的形式额外存放.但实现上述功能的后端代码从5.4.2之后都被主干源码合并.
所以,单纯使用最新版的AMQ,是无法得到这个AJAX多客户端的功能的,需要自己额外进行调整.
今天上午解决了这个问题,稍稍修改了一下_amq.js文件,保证了与原接口的一致性,又增加了initClientId方法,可以方便的使用AMQ的AJAX多客户端功能了.
使用时,可以将这个_amq.js替换原activemq_web-x.x.x.jar中的文件,同时在调用页面中,进行最初uri赋值的时候,顺手调用一下amq.initClientId();就可以开启这个功能了.
刚刚进行代码测试,初步通过,功能的正确性得到了初步验证.
如果有同学遇到了相同的问题,希望能够帮忙进行测试调整.
文章系本人原创，转载请注明出处和作者,本文原址在http://h-rain.iteye.com/blog/1387640
/** * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements.See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License.You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */// AMQ Ajax handler// This class provides the main API for using the Ajax features of AMQ. It// allows JMS messages to be sent and received from javascript when used// with the org.apache.activemq.web.MessageListenerServlet//var amq ={// The URI of the MessageListenerServleturi: '/amq',// Polling. Set to true (default) if waiting poll for messages is neededpoll: true, // Poll delay. if set to positive integer, this is the time to wait in ms before// sending the next poll after the last completes._pollDelay: 0,_clientIdStr:'',_first: true,_pollEvent: function(first) {},_handlers: new Array(),_messages:0,_messageQueue: '',_queueMessages: 0,//init the clientId,default auto make as Date stringinitClientId:function(newId){if (newId)amq._clientIdStr="clientId="+newId;elseamq._clientIdStr="clientId="+(new Date()).getTime().toString();},//using clientId,whit separtor_makeClientIdStr:function(spChar){var SC=spChar||'';if (amq._clientIdStr=='')return '';return SC+amq._clientIdStr;},_messageHandler: function(request){ try { if (request.status == 200) { var response = request.responseXML.getElementsByTagName("ajax-response"); if (response != null && response.length == 1) { for ( var i = 0 ; i < response.childNodes.length ; i++ ) { var responseElement = response.childNodes; // only process nodes of type element..... if ( responseElement.nodeType != 1 ) continue; var id = responseElement.getAttribute('id'); var handler = amq._handlers; if (handler!=null) { for (var j = 0; j < responseElement.childNodes.length; j++) { handler(responseElement.childNodes); } } } } } } catch(e) { alert(e); }},startBatch: function(){ amq._queueMessages++;},endBatch: function(){ amq._queueMessages--; if (amq._queueMessages==0 && amq._messages>0) { var body = amq._messageQueue; amq._messageQueue=''; amq._messages=0; amq._queueMessages++; new Ajax.Request(amq.uri, { method: 'post', postBody: body+amq._makeClientIdStr('&'), onSuccess: amq.endBatch}); }},_pollHandler: function(request){ amq.startBatch(); try { amq._messageHandler(request); amq._pollEvent(amq._first); amq._first=false; } catch(e) { alert(e); } amq.endBatch(); if (amq._pollDelay>0) setTimeout('amq._sendPoll()',amq._pollDelay); else amq._sendPoll();}, _sendPoll: function(request){ new Ajax.Request(amq.uri, { method: 'get', parameters: amq._makeClientIdStr(),onSuccess: amq._pollHandler });},// Add a function that gets called on every poll response, after all received// messages have been handled.The poll handler is past a boolean that indicates// if this is the first poll for the page.addPollHandler : function(func){ var old = amq._pollEvent; amq._pollEvent = function(first) { old(first); func(first); }},// Send a JMS message to a destination (eg topic://MY.TOPIC).Message should be xml or encoded// xml content.sendMessage : function(destination,message){ amq._sendMessage(destination,message,'send');},// Listen on a channel or topic. handler must be a function taking a message arguementaddListener : function(id,destination,handler){ amq._handlers=handler; amq._sendMessage(destination,id,'listen');},// remove Listener from channel or topic.removeListener : function(id,destination){ amq._handlers=null; amq._sendMessage(destination,id,'unlisten');},_sendMessage : function(destination,message,type){ if (amq._queueMessages>0) { if (amq._messages==0) { amq._messageQueue='destination='+destination+'&message='+message+'&type='+type; } else { amq._messageQueue+='&d'+amq._messages+'='+destination+'&m'+amq._messages+'='+message+'&t'+amq._messages+'='+type; } amq._messages++; } else { amq.startBatch(); new Ajax.Request(amq.uri, { method: 'post', postBody: 'destination='+destination+'&message='+message+'&type='+type+amq._makeClientIdStr('&'), onSuccess: amq.endBatch}); }}, _startPolling : function(){ if (amq.poll) new Ajax.Request(amq.uri, { method: 'get', parameters: 'timeout=10'+amq._makeClientIdStr('&'), onSuccess: amq._pollHandler });}};Behaviour.addLoadEvent(amq._startPolling);function getKeyCode(ev){ var keyc; if (window.event) keyc=window.event.keyCode; else keyc=ev.keyCode; return keyc;}
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