[Stripes-users] StreamingResolution, temporary files, and Exceptions

[William K. <kr...@3f...>]

In my web application, I have code that generates a temporary file (based
on user input) and streams it back to the user using a StreamingResolution.

The initial implementation had a utility method that generated the file and
passed back an InputStream...

public Resolution exportCsv() throws IOException {
  InputStream is = getCsvData();
  StreamingResolution sr = new
StreamingResolution(Constants.CONTENT_TYPE_CSV, is);
  sr.setFilename("export.csv");
  return sr;
}

However, I want to be able to clean up the temporary file after it has been
streamed to the user.
I thought that I could use the anonymous inner class method described in
the stripes javadocs...

public Resolution exportCsv() throws IOException {
  return new StreamingResolution(Constants.CONTENT_TYPE_CSV) {
    public void stream(HttpServletResponse response) throws Exception {
      File tempFile = null;
      InputStream is = null;
      try {
        tempFile = File.createTempFile(UUID.randomUUID().toString(), null);
        getCsvData(tempFile);
        is = new FileInputStream(tempFile);
        IOUtils.copy(is, response.getOutputStream());
        is.close();
      }
      catch(IOException e) {
        logger.error("Unable to export to csv file: " + e);
        throw new IOException();
      }
      finally {
        IOUtils.closeQuietly(is);
        FileUtils.deleteQuietly(tempFile);
      }
    }
  }.setFilename("export.csv");
}


I'm finding that if there's an exception, whatever error page my
application generates gets streamed back to the user in a file called
"export.csv".  So this method isn't really viable, at least the way I'm
using it.

Is there a pattern for this sort of thing in Stripes?