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From "Gabriel Belingueres" <belingue...@gmail.com>
Subject Re: [OT] S2 Stream Result, downloading large file, advice needed
Date Sat, 23 Aug 2008 13:12:57 GMT
IMO the best solution is the one that download the files faster. The
faster the files download, the quicker the response will finish and
another user can download a file.

Whether you store all the file in memory or in a temp file could be
irrelevant if the server have a low bandwidth network connection.

The bottom line is: you should stress test your app to know what will
happen to the server on high load.

2008/8/22 Brendan Billingsley <billinb@nsidc.org>:
> I have a somewhat similar situation in an application I am creating where I
> needed to provide a .tar.gz file that I create for the user. I want that
> file to hang around for some configurable amount of time in case the user
> re-requests that file and then I wanted to remove it.
>
> I used quartz to periodically run a cleanup method to remove old files.
> Right now it is running once a day to delete any file older then 72 hours
> but that can all be changed in my spring configuration later on if we have
> too many files sticking around.
>
> I am extending the StreamResult class to return my tar file for downloaded.
>
> Hope this helps. I can provide more detail into some or all of the above if
> you want. I don't really think that the details of quartz and/or spring
> belong on this list so if you want information about that feel free to
> contact me off list.
>
> -Brendan
>
> Greg Lindholm wrote:
>>
>> I'm still interested in hear any suggestions. I know that this is not
>> strictly an S2 issue but it is related to using a Stream result type.  If
>> I
>> was writing a servlet I would just get the OutputStream and write directly
>> to it, putting the burden of buffering etc. onto the container.
>>
>> What I decided to do (until I hear a better suggestion) is to write to a
>> temporary file (File.createTempFile()) then for the InputStream I created
>> a
>> wrapper around FileInputStream which will delete the file when close() is
>> called.  This seems to work fine in the conditions I can test, not sure if
>> close() will be called if the user hits Cancel in the middle of a very
>> large
>> download.
>>
>>
>>
>>
>> Greg Lindholm wrote:
>>
>>>
>>> Hi Folks,
>>> I'm using S2 Stream result type to allow users to download a CSV "file"
>>> that I dynamically write from records selected from a database.
>>>
>>> First pass on this I'm using a StringWriter to write out the CSV data
>>> (using SuperCSV) that using the string to build a ByteArrayInputStream
>>> for
>>> the InputStream result.
>>>
>>> My concern is that the results could get very large based on the the
>>> selection criteria the user supplies. So trying to do this all in-memory
>>> with a StringWriter->String->Byte[] is likely a bad idea.
>>>
>>> I'm looking for advice on a better way of doing this?  I thought I could
>>> write to a temp file, but how do I ensure the file is
>>> deleted when the download completes?
>>> I also thought about using a PipedInputStream and hooking to a
>>> PipedOutputStream which I write to in another thread, but this seems like
>>> it could become overly complicated having to deal with the threads and
>>> database sessions and error conditions etc.
>>>
>>> Do you know a better way?
>>>
>>> Any advice or suggestions would be appreciated.
>>>  Thanks
>>> Greg
>>>
>>>
>>>
>>>
>>>
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>>>
>>>
>>
>>
>
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