Question

我正在处理一个大型的Grails 1.3.7项目，我想从过滤器访问流状态名称以进行日志记录。我一直在谷歌搜索，我能找到的最接近的答案是：Grails WebFlow State Name，但它只能在流程本身内工作。

有没有办法从流程外（过滤器）获取当前会话中正在执行的流的状态名称？

提前致谢，

吉列尔莫

Answer 1

经过大量的谷歌搜索和调试后，我设法生成以下代码。它适用于简单的应用程序。当我从假期回来时，我会将它与主应用程序集成，然后我会更新这个问题。

package org.glalejos

import org.springframework.context.ApplicationContext
import org.springframework.webflow.context.ExternalContext
import org.springframework.webflow.context.ExternalContextHolder
import org.springframework.webflow.context.servlet.ServletExternalContext
import org.springframework.webflow.execution.FlowExecution
import org.springframework.webflow.execution.FlowExecutionKey
import org.springframework.webflow.execution.repository.FlowExecutionRepository

class LoggingFilters {

    def grailsApplication

    String getFlowStateName(def grailsApplication, def servletContext, def request, def response) {
        String stateName

        if (grailsApplication && servletContext && request && request.queryString && response) {
            try {
                String strKey = null
                String[] keys = request.queryString.split("&")
                keys.each{ if (it.startsWith("execution=")) strKey = it.substring(10)}

                if (strKey != null) {
                    ApplicationContext ctx = grailsApplication.mainContext
                    FlowExecutionRepository fer = ctx.getBean("flowExecutionRepository")

                    FlowExecutionKey fek = fer.parseFlowExecutionKey(strKey)

                    ExternalContext previousContext = ExternalContextHolder.getExternalContext()

                    try {
                        // You have to set an external context before invoking "fer.getFlowExecution()" or it'll throw a NPE 
                        ExternalContextHolder.setExternalContext(new ServletExternalContext(servletContext, request, response));
                        FlowExecution fe = fer.getFlowExecution(fek)

                        stateName = fe.getActiveSession().getState().getId()
                    } finally {
                        ExternalContextHolder.setExternalContext(previousContext);
                    }
                } else {
                    stateName = null
                }
            } catch(Exception e) {
                stateName = null
            }
        } else {
            stateName = null
        }

        return stateName
    }

    def filters = {
        logData(controller:"*", action:"*") {
            before = {
                println("Incoming request. Current flow state name is: ${getFlowStateName(grailsApplication, servletContext, request, response)}")
            }

            after = {
                println("Dispatched request. Current flow state name is: ${getFlowStateName(grailsApplication, servletContext, request, response)}")
            }
        }
    }
}

编辑：上面的代码可以确定给定时间点当前流状态的名称，但它不会像流程一样更新日志框架的映射诊断上下文执行发展。为此，有必要实现org.springframework.webflow.execution.FlowExecutionListener并在conf/spring/resources.groovy中注册它：

beans = {
    myLoggingFlowExecutionListener(org.example.MyLoggingFlowExecutionListener)
}

您必须在hibernateConversationListener bean中注册此侦听器bean和executionListenerLoader bean，但由于某种原因，Spring DSL在这种情况下不起作用（请参阅下面的EDIT2）。因此，resources.xml可以放在与resources.groovy相同的文件夹中，以便正确声明您的资源：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">

  <bean id="executionListenerLoader" class="org.springframework.webflow.execution.factory.StaticFlowExecutionListenerLoader">
    <constructor-arg>
      <list>
        <ref bean="hibernateConversationListener" />
        <ref bean="myLoggingFlowExecutionListener" />
      </list>
    </constructor-arg> 
  </bean>
</beans>

每个FlowExecutionListener方法都会收到大量可用于记录目的的上下文信息（为清楚起见，我省略了此类的实现）。

EDIT2 ：在流的生命周期中操作域对象时，未能将hibernateConversationListener bean添加到executionListenerLoader会导致Hibernate异常。但是，Spring DSL在这种特定情况下不起作用，因此我必须使用XML格式声明所需的bean。见http://grails.1312388.n4.nabble.com/Registering-custom-flow-execution-listener-td2279764.html。我已将上面的代码更新为最终的，有效的版本。

从过滤器访问流状态名称

1 个答案: