Xpath base64Decode在Wso2Esb 4.8.1中不起作用

Question

我收到了我需要解码的base64流。我正在做一些研究，但我被卡住了，这是我的代码：

<outSequence>
     <property name="cadena" value="Hola mundo" scope="default" type="STRING"/>
     <property name="cadena64"
               expression="base64Encode(get-property('cadena'))"
               scope="default"
               type="STRING"/>
     <property 
               name="cadenaASCII"
               expression="syn:base64Decode(syn:get-property('cadena64'))"
               scope="default"
               type="STRING"/>
     <payloadFactory media-type="json">
        <format>
          {"cadena":"$1",
            "cadena64":"$2",
            "cadenaASCII":"$3",
          }
        </format>
        <args>
           <arg evaluator="xml" expression="get-property('cadena')"/>
           <arg evaluator="xml" expression="get-property('cadena64')"/>
           <arg evaluator="xml" expression="get-property('cadenaASCII')"/>
        </args>
     </payloadFactory>
     <send/>
  </outSequence>

我通过取消注释该行来启用Xpath 2.0

synapse.xpath.dom.failover.enabled=true

位于$ ESB_HOME / repository / conf目录（并重新启动服务）。

这是我得到的错误：

Evaluation of the XPath expression syn:base64Decode(syn:get-property('cadena64')) resulted in an error  More TID[-1234] [ESB] [2019-03-04 19:27:23,359] ERROR {org.apache.synapse.util.xpath.SynapseXPath} - Evaluation of the XPath expression syn:base64Decode(syn:get-property('cadena64')) resulted in an error net.sf.saxon.xpath.XPathEvaluator.compile(XPathEvaluator.java:378) org.apache.synapse.util.xpath.SynapseXPath.evaluateDOMXPath(SynapseXPath.java:529) org.apache.synapse.util.xpath.SynapseXPath.stringValueOf(SynapseXPath.java:364) org.apache.synapse.mediators.builtin.PropertyMediator.getResultValue(PropertyMediator.java:302) org.apache.synapse.mediators.builtin.PropertyMediator.mediate(PropertyMediator.java:96) org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:77) org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:47) org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:131) org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:268) org.apache.synapse.core.axis2.SynapseCallbackReceiver.handleMessage(SynapseCallbackReceiver.java:488) org.apache.synapse.core.axis2.SynapseCallbackReceiver.receive(SynapseCallbackReceiver.java:170) org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180) org.apache.synapse.transport.passthru.ClientWorker.run(ClientWorker.java:225) org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) java.lang.Thread.run(Thread.java:745) 

Answer 1

我认为只有编码在4.8.1中得到支持/实现，否则如前所述，一个选项是升级esb。以下内容适用于4.8.1

   <property name="contentBase64" expression="//t:Content" scope="default" type="STRING"/>

<script language="js"><![CDATA[importPackage(Packages.org.apache.commons.codec.binary); var log = mc.getServiceLog();      log.info("1");var c = mc.getProperty("contentBase64");log.info("2:"+c);var bc = Base64.decodeBase64(c);log.info("3:"+bc);  var result = "";  for(var i = 0; i                                                                                                                               
                                             < bc.length; ++i){     result+= (String.fromCharCode(bc[i]));  }   log.info("result:"+result);      mc.setProperty("contentDecoded", result);]]></script>

可以在属性“内容编码”中访问解码的内容。

希望有所帮助。

Answer 2

您引用的错误包含格式错误的堆栈跟踪：

Evaluation of the XPath expression syn:base64Decode(syn:get-property('cadena64')) resulted in an error  
More TID[-1234] [ESB] [2019-03-04 19:27:23,359] ERROR {org.apache.synapse.util.xpath.SynapseXPath} - 
Evaluation of the XPath expression syn:base64Decode(syn:get-property('cadena64')) resulted in an error 
net.sf.saxon.xpath.XPathEvaluator.compile(XPathEvaluator.java:378) 
org.apache.synapse.util.xpath.SynapseXPath.evaluateDOMXPath(SynapseXPath.java:529) 
....

这给了我们一些信息，但没有我们想要的那么多。它告诉我们，Saxon正在评估XPath表达式，它告诉我们Saxon在表达式中报告了一个静态错误。它还告诉我们它是Saxon的一个相当古老的版本，因为至少从Saxon 9.6开始发布，类XPathEvaluator包含大约330行。它没有告诉我们的是错误究竟是什么。

糟糕的诊断似乎是Apache突触的责任。

我担心这只是回答问题的一小步，但我希望这些信息对某人有用。

Answer 3

您的代码在ESB 5.0.0中工作，所以没有帮助（但升级将是您的问题的解决方案！）我发现它怀疑虽然Encode正在工作而Decode不是。你可以尝试没有base64Decode没有syn:吗？