Delete file when the file downloaded.

[vikas byn]

I have to implement a functionality - delete the file on server when user download file is complete. we do not want store that file on server anymore.

I m using struts2 for downloading file on tomcat server. How can i identify file downloading is complete. as of now, i can download file successfully but when the file should be deleted?

code in action class:

	contentType=new MimetypesFileTypeMap().getContentType(fileName);
	File f=new File("/home/vikasbarsaiyan/downloadables/"+fileName);
        inputStream = new  FileInputStream(f);

struts.xml
-----------------
<action name="downloadFile" class="mypack.action.FileTransferAction" method="downloadFile"> <result name="success" type="stream"> <param name="contentType">${contentType}</param> <param name="inputName">inputStream</param> <param name="contentDisposition">filename="${fileName}"</param> <param name="bufferSize">4096</param> </result> </action>

[Mohana Rao Sv]

write a custom interceptor to delete the file and make sure that this will be executed only after successful completion of downloading file. Ask me if you have any doubts.

[vikas byn]

is there any way, to identify end of stream?

[Orton K Randy]

Mind using AJAX? Here's a comprehensive solution that you can relate your question to. Here's a bit more insight into the same. Or even this could be of some help.

Not into AJAX? The following code snippet in your servlet is supposed to let you know if the download has completed.

ServletOutputStream op = response.getOutputStream();  
File f = new File(String.valueOf(dirPath).concat(String.valueOf(filename)));
int length = 0;
response.setContentType("application/unknown");
response.setContentLength((int)f.length());
response.setHeader("Content-Disposition", String.valueOf(String.valueOf("attachment; filename=\"").concat(String.valueOf(filename))).concat(String.valueOf("\"")));
byte[] bbuf = new byte[10240];
DataInputStream in = new DataInputStream(new FileInputStream(f));
while (in != null) { 
      if ((length = in.read(bbuf)) == -1)
          break;
      op.write(bbuf, 0, length);    
}
System.out.println("out of loop");      
in.close();
op.flush();
op.close();

Supposedly, the file download will be completed as soon as the while loop is exited.
Hope that helps.

[vikas byn]

Mohana Rao wrote:write a custom interceptor to delete the file and make sure that this will be executed only after successful completion of downloading file. Ask me if you have any doubts.

actually I am not sure about Interceptor is the good idea. Intercept just intercept the Action execution. It will not have information when the end of stream occurred. Browser transfer files over http So i think there is something different kind of solution.

[Mohana Rao Sv]

Interceptors are objects that dynamically intercept Action invocations. They provide the developer with the opportunity to define code that can be executed before and/or after the execution of an action. They also have the ability to prevent an action from executing. Interceptors provide developers a way to encapulate common functionality in a re-usable form that can be applied to one or more Actions. So, write an interceptor which is responsible for deleting the file. It(Interceptors) will not be called until and unless you result execution is successful.

[vikas byn]

Mohana Rao wrote: Interceptors are objects that dynamically intercept Action invocations. They provide the developer with the opportunity to define code that can be executed before and/or after the execution of an action. They also have the ability to prevent an action from executing. Interceptors provide developers a way to encapulate common functionality in a re-usable form that can be applied to one or more Actions. So, write an interceptor which is responsible for deleting the file. It(Interceptors) will not be called until and unless you result execution is successful.

thanks for your help.