I could be wrong, but it sounded to me like he was generating the CSV file
on the filesystem based on user-input. So it could be a file being created
out of the database. If the CSV file can be very large, he definitely
should keep it on the file system and use buffered streams to send it back
to the client. Otherwise, he stands to consume a lot of memory on the
server which is bad.
It's very easy to delete the temporary file in a finally block with a high
confidence that the deletion won't fail.
-- Rick
On Thu, Jul 9, 2015 at 6:27 PM, Nestor Hernandez <ilu...@gmail.com> wrote:
> Your method getExportCsv could be like this:
>
> getExportCsv (outpustream){
> //Write to the outpustream
> }
>
> And there is no need of temp files !
> Cheers
> El 9/7/2015 18:07, "Nestor Hernandez" <ilu...@gmail.com> escribió:
>
>> Well, I think that that could be much better like this. Just write to the
>> response outpustream.
>>
>> return new StreamingResolution() {
>> public void stream(request, response){
>> getExportCsv(response.getOutputstream());
>> }
>> }
>> El 9/7/2015 17:48, "William Krick" <kr...@3feetunder.com> escribió:
>>
>>> Sorry to dig up an old thread but I was working on another project for a
>>> while and now I'm coming back to the original project and the
>>> StreamingResolution issue.
>>>
>>> The hybrid solution posted by Ben Gunter seems to work well. Thank you.
>>>
>>> I have two questions/concerns.
>>>
>>> 1) I see why tempFile needs to be declared final (to access it inside of
>>> the StreamingResolution), and I also see why it needs to be an array where
>>> we reference item 0 (to get around it being final for the method that
>>> populates the temp file and creates the InputStream), but it really looks
>>> and feels like a hack. Isn't there a better way to do this that isn't so
>>> hacky?
>>>
>>> 2) I'm doing this same thing (populating a temp file, streaming it to
>>> the user, deleting the temp file) in a lot of places in a multi-page web
>>> application. Is there a clean way to encapsulate these 20-something lines
>>> of code into a class so that I'm not copy/pasting boilerplate code over and
>>> over again?
>>>
>>> Thanks
>>>
>>>
>>> On Tue, Jun 24, 2014 at 8:25 AM, Ben Gunter <bgun...@cpons.com> wrote:
>>>
>>>> Yes, sort of a hybrid of your two approaches.
>>>>
>>>> public Resolution exportCsv() throws IOException {
>>>> final File tempFile[] = { null };
>>>> final InputStream is;
>>>> try {
>>>> tempFile[0] =
>>>> File.createTempFile(UUID.randomUUID().toString(), null);
>>>> getCsvData(tempFile[0]);
>>>> is = new FileInputStream(tempFile[0]);
>>>> } catch (IOException e) {
>>>> logger.error("Unable to export to csv file: " + e);
>>>> throw new IOException();
>>>> } finally {
>>>> FileUtils.deleteQuietly(tempFile[0]);
>>>> }
>>>>
>>>> return new StreamingResolution(Constants.CONTENT_TYPE_CSV, is) {
>>>> public void stream(HttpServletResponse response) throws
>>>> Exception {
>>>> try {
>>>> super.stream(response);
>>>> } finally {
>>>> FileUtils.deleteQuietly(tempFile[0]);
>>>> }
>>>> }
>>>> }.setFilename("export.csv");
>>>> }
>>>>
>>>>
>>>> On Mon, Jun 23, 2014 at 5:33 PM, William Krick <kr...@3feetunder.com>
>>>> wrote:
>>>>
>>>>> 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?
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ------------------------------------------------------------------------------
>>>>> Open source business process management suite built on Java and Eclipse
>>>>> Turn processes into business applications with Bonita BPM Community
>>>>> Edition
>>>>> Quickly connect people, data, and systems into organized workflows
>>>>> Winner of BOSSIE, CODIE, OW2 and Gartner awards
>>>>> http://p.sf.net/sfu/Bonitasoft
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>>>>> Stripes-users@lists.sourceforge.net
>>>>> https://lists.sourceforge.net/lists/listinfo/stripes-users
>>>>>
>>>>>
>>>>
>>>>
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>>>> Turn processes into business applications with Bonita BPM Community
>>>> Edition
>>>> Quickly connect people, data, and systems into organized workflows
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>>>>
>>>
>>>
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