具有响应处理的WSO2 ESB（Apache Synapse）代理

又是我 . 作为一项技术练习，我试图使用WSO2 ESB来代理一些网络流量 . 具体来说，我试图代理网络流量并动态改变返回的响应，如下所示：

• 让ESB收到HTTP请求

• 将请求代理到特定服务器

• 收到回复

• 找到"sad"一词的任何出现，并将其替换为"happy"（不区分大小写的正则表达式）

• 将更改的响应传递回浏览器

有人会认为这是一个简单的正则表达式或XSLT操作，但事实证明这比我想象的要困难得多 . 目前，这是我正在使用的代理脚本......

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
       name="PassProxy"
       transports="https http"
       startOnLoad="true"
       trace="disable">
   <description>Route content from a web server through the ESB service and alter it</description>
   <target>
      <endpoint>
         <address uri="http://server.yoyodyne.com/"/>
      </endpoint>
      <inSequence/>
      <outSequence>
         <property name="TheContentIncludingTheSoapEnvelope" expression="."/>
         <property xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                   xmlns:ns="http://org.apache.synapse/xsd"
                   name="TheContentFromSoapBodyButNotReally"
                   expression="//soapenv:Envelope/soapenv:Body/*"/>
         <property name="TheContent"
                   value="An initial value that should be replaced"
                   scope="default"
                   type="STRING"/>
         <enrich>
            <source type="body" clone="true"/>
            <target type="property" property="TheContent"/>
         </enrich>
         <property name="ContentType" expression="$trp:Content-Type"/>
         <property name="ContentLength" expression="$trp:Content-Length"/>
         <log level="custom">
            <property name="ContentType" expression="$trp:Content-Type"/>
            <property name="ContentLength" expression="$trp:Content-Length"/>
            <property name="MessageVar" value="TheContent"/>
            <property name="TargetMessage" expression="get-property('TheContent')"/>
         </log>
         <script language="js">
            //hack because xpath fn:replace does not work in property tags and fn:translate works on chars not whole strings
            var contentType=mc.getProperty('ContentType');
            var contentObject=mc.getProperty('TheContent'); //how to get the text of this? And do it in un-escaped format???
            if(/text/i.test(contentType)) {
                if(!contentObject) {
                    mc.setProperty('TheAlteredContent','Well that didn\'t work as expected');
                } else {
                    if(typeof contentObject == 'object' || typeof contentObject == 'undefined') {
                        var returnMessage='';
                        for (var key in contentObject) {
                            returnMessage=returnMessage+'found key "'+key+'"\n';
                        } //end object key for
                        returnMessage='Can\'t work with this type of input - '+typeof contentObject+'n\Available keys to try:\n'+returnMessage;
                        contentObject=returnMessage;
                    } else {
                        contentObject=contentObject.replaceAll('sad', 'happy');
                        //more regex statements to go here
                    } //end typeof if
                } //end property check if
            } else {
                //not text - do nothing
                contentObject='binary content (I think). Found content type of "'+contentType+'"';
            } //end content type check if
            //send the content back
            mc.setProperty('TheAlteredContent',contentObject);
         </script>
         <enrich>
            <!-- need to figure out how to replace the content and not append to the end of it. Replace tag on target keeps getting removed for some reason -->
            <source type="property" property="TheAlteredContent" clone="true"/>
            <target type="body"/>
         </enrich>
         <!-- doctype headers in the HTML cause logging to fail, so no debugging for you -->
         <!--<log level="full"/>-->
         <send/>
      </outSequence>
   </target>
</proxy>

使用富集操作授予可能不是处理此问题的最佳方法，但它在当时似乎是一个好主意 . 最终发生的事情是，响应的HTML部分作为具有转义内容的对象传递到JS代码中（或传递出来???） . 因为“contentObject”var是正则表达式失败的对象 . 使用toString（）将“contentObject”强制转换为字符串也不起作用 . 即使它确实有效，HTML内容仍然是转义形式，并且转换回来可能会有问题，因为HTML代码中可能存在可能需要保留HTML格式的转义条目 . 这里的最后一个问题是“TheAlteredContent”属性的内容被附加到内容而不是替换它，即使将属性“action = replace”添加到最终的富集操作中（ESB实际上将其删除） .

任何人都知道如何更好地做到这一点，或者也许是一种方法来使上述代码工作？