用户在Grails中取消了文件下载 [英] User cancelled file download in Grails

问题描述

如何正确处理已取消的文件下载？有问题的文件是一个非常大的zip文件，需要很长时间才能生成，因此用户有足够的时间在他的下载对话框窗口中点击取消按钮。

发生这种情况时，会发生一个令人讨厌的异常（请参见下文），因为客户端破坏了管道。但如何清理它？

谢谢。

$ b $在哪里/有什么正确的方法来捕捉异常，以便tomcat日志不会被他们遗弃？下载代码本身就是教科书中非常标准的代码：

  import java.util.zip.ZipEntry 
 import java.util.zip.ZipOutputStream 
 $ b $ def getZipFile（params）{
 response.setHeader（Expires，0）; 
 response.setHeader（Cache-Control，must-revalidate，post-check = 0，pre-check = 0）; 
 response.setHeader（Pragma，public）; 
 response.setHeader（Content-Disposition，attachment; filename = \filename.zip \）; 
 response.contentType =application / zip
 
 def zos = new ZipOutputStream（response.outputStream）
 zos = functionThatCreatesTheZipFile（zos，params）//这需要一些时间
 zos.close（）
} 
  

例外：

  rfpmgr [2013-05-01 10:14:32.337]错误：web.errors.GrailsExceptionResolver处理请求时发生IOException：[GET] / rfpManager / report / downloadZipFile 
 Stacktrace如下：
 java.io.IOException $ b $ java.util.zip.ZipOutputStream.writeBytes（ZipOutputStream.java:617）$ b $ java.util.zip .ZipOutputStream.writeCEN（ZipOutputStream.java:501）
 at java.util.zip.ZipOutputStream.finish（ZipOutputStream.java:348）
 at java.util.zip.DeflaterOutputStream.close（DeflaterOutputStream.java ：238）
 at java.util.zip.ZipOutputStream.close（ZipOutputStream.java:360）
 at gov.usgs.eventManager.ZipService.getZipFile（ZipService.groovy：32）
 at gov.usgs.eventManager.ReportController $ _closu re18.doCall（ReportController.groovy：738）
 at gov.usgs.jdt.jos.spring.JOSSOProcessingFilter.doFilter（JOSSOProcessingFilter.java:144）
 at gov.usgs.jdt.josso.agent。 GenericServletSSOAgentFilter.doFilter（GenericServletSSOAgentFilter.java:431）$ b $在java.lang.Thread.run（Thread.java:722）
 rfpmgr [2013-05-01 10:14:32.354]错误：web。 errors.GrailsExceptionResolver处理请求时发生IllegalStateException：[GET] / rfpManager / report / downloadZipFile 
 getOutputStream（）已被调用以用于此响应。 Stacktrace如下：
 org.codehaus.groovy.grails.web.pages.exceptions.GroovyPagesException：处理GroovyPageView时出错：getOutputStream（）已经在gov.usgs.jdt.jos中为此响应
调用。 spring.JOSSOProcessingFilter.doFilter（JOSSOProcessingFilter.java:144）
 at gov.usgs.jdt.jos.gent.GenericServletSSOAgentFilter.doFilter（GenericServletSSOAgentFilter.java:431）
 at java.lang.Thread.run（ Thread.java:722）
导致：java.lang.IllegalStateException：getOutputStream（）已被调用此响应
在gsp_rfpManager_errorserrors_gsp.run（gsp_rfpManager_errorserrors_gsp.groovy：17）
 .. 。3 more 
  

解决方案

这似乎工作得很好：

  import java.util.zip.ZipEntry 
 import java.util.zip.ZipOutputStream 
导入组织。 apache.catalina.connector.ClientAbortException 
 $ b $ def getZipFile（params）{
 response.setHeader（Expires，0）; 
 response.setHeader（Cache-Control，must-revalidate，post-check = 0，pre-check = 0）; 
 response.setHeader（Pragma，public）; 
 response.setHeader（Content-Disposition，attachment; filename = \filename.zip \）; 
 response.contentType =application / zip
 
 try {
 def zos = new ZipOutputStream（response.outputStream）
 zos = functionThatCreatesTheZipFile（zos，params）/ /这需要一些时间
 zos.close（）
} 
 catch（ClientAbortException ex）{
 printlnuser aborted download
} 
} 
  

How to properly handle a cancelled file download? The file in question is a pretty large zip file that takes a long time to build, so the user has plenty of time to hit the Cancel button on his download dialog window.

When it happens, a nasty Exception occurs (see below), which is expected, since the client broke the pipe. But how to clean it up? Where/What's the proper way to catch the Exception so that the tomcat logs are not littered with them?

Thank you.

The download code itself is pretty standard code from the textbook:

import java.util.zip.ZipEntry
import java.util.zip.ZipOutputStream

def getZipFile(params) {   
  response.setHeader("Expires", "0");
  response.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
  response.setHeader("Pragma", "public");
  response.setHeader("Content-Disposition", "attachment; filename=\"filename.zip\"");
  response.contentType = "application/zip"

  def zos = new ZipOutputStream(response.outputStream)
  zos = functionThatCreatesTheZipFile(zos, params) // this takes some time
  zos.close()
}

Exception:

rfpmgr [2013-05-01 10:14:32.337] ERROR: web.errors.GrailsExceptionResolver IOException occurred when processing request: [GET] /rfpManager/report/downloadZipFile
Stacktrace follows:
java.io.IOException
at java.util.zip.ZipOutputStream.writeBytes(ZipOutputStream.java:617)
at java.util.zip.ZipOutputStream.writeCEN(ZipOutputStream.java:501)
at java.util.zip.ZipOutputStream.finish(ZipOutputStream.java:348)
at java.util.zip.DeflaterOutputStream.close(DeflaterOutputStream.java:238)
at java.util.zip.ZipOutputStream.close(ZipOutputStream.java:360)
at gov.usgs.eventManager.ZipService.getZipFile(ZipService.groovy:32)
at gov.usgs.eventManager.ReportController$_closure18.doCall(ReportController.groovy:738)
at gov.usgs.jdt.josso.spring.JOSSOProcessingFilter.doFilter(JOSSOProcessingFilter.java:144)
at gov.usgs.jdt.josso.agent.GenericServletSSOAgentFilter.doFilter(GenericServletSSOAgentFilter.java:431)
at java.lang.Thread.run(Thread.java:722)
rfpmgr [2013-05-01 10:14:32.354] ERROR: web.errors.GrailsExceptionResolver IllegalStateException occurred when processing request: [GET] /rfpManager/report/downloadZipFile
getOutputStream() has already been called for this response. Stacktrace follows:
org.codehaus.groovy.grails.web.pages.exceptions.GroovyPagesException: Error processing GroovyPageView: getOutputStream() has already been called for this response
at gov.usgs.jdt.josso.spring.JOSSOProcessingFilter.doFilter(JOSSOProcessingFilter.java:144)
at gov.usgs.jdt.josso.agent.GenericServletSSOAgentFilter.doFilter(GenericServletSSOAgentFilter.java:431)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.IllegalStateException: getOutputStream() has already been called for this response
at gsp_rfpManager_errorserrors_gsp.run(gsp_rfpManager_errorserrors_gsp.groovy:17)
... 3 more

解决方案

This seems to work just fine:

import java.util.zip.ZipEntry
import java.util.zip.ZipOutputStream
import org.apache.catalina.connector.ClientAbortException

def getZipFile(params) {   
  response.setHeader("Expires", "0");
  response.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
  response.setHeader("Pragma", "public");
  response.setHeader("Content-Disposition", "attachment; filename=\"filename.zip\"");
  response.contentType = "application/zip"

  try {
    def zos = new ZipOutputStream(response.outputStream)
    zos = functionThatCreatesTheZipFile(zos, params) // this takes some time
    zos.close()
  }
  catch (ClientAbortException ex) {
    println "user aborted download"
  }
}

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