[Midas] Using pydas to identify bitstream location

[Zach Mullen]

Interesting. If you know the root path of the assetstore, you can derive
the full path based on the bitstream's md5sum, which is exposed in the API.

Bitstreams are always stored in a two-level nested directory structure
under the assetstore root path, and those two directories are just prefixes
of the md5sum. For example, if my assetstore is
at /Users/zach/dev/midas/data/assetstore/ and my bitstream has
md5sum=66c1d0d9132ec15ae8f238e4767753a8, then the path of the bitstream on
disk
is /Users/zach/dev/midas/data/assetstore/66/c1/66c1d0d9132ec15ae8f238e4767753a8.

This is sufficient if you hard-code the assetstore path, but a more general
solution would involve creating a new API endpoint to expose assetstores
(such an endpoint doesn't exist yet).

HTH,

Zach


On Thu, Oct 31, 2013 at 1:43 AM, BRIAN E CHAPMAN <Brian.Chapman at utah.edu>wrote:

>  Zach and JC,
>
>  What I'm envisioning is something similar to what JC describes. I'm
> playing around with using an IPython notebook as a web-based means of data
> exploration via SimpleITK, OpenCV, etc. So I was hoping to be able to
> figure out from pydas where the file was located on the disk and pass that
> to the reader (e.g., SimpleITK image reader).
>
>  Brian
>
> ------------------------------
> *From:* Jean-Christophe Fillion-Robin [jchris.fillionr at kitware.com]
> *Sent:* Wednesday, October 30, 2013 5:54 PM
> *To:* Zach Mullen
> *Cc:* BRIAN E CHAPMAN; midas at public.kitware.com
> *Subject:* Re: [Midas] Using pydas to identify bitstream location
>
>    Hi Zach,
>
>  I guess for performance purpose, if one would like to have a common
> file-system between a processing/visualization server and midas server.
> Knowing the location of the bitstream would avoid unneeded streaming
> operation.
>
>  Jc
>
>
> On Wed, Oct 30, 2013 at 7:43 PM, Zach Mullen <zach.mullen at kitware.com>wrote:
>
>> Hi Brian,
>>
>>  The location of a bitstream on the server's filesystem is known only to
>> the server, it isn't exposed in the API in any way. As such, it wouldn't be
>> possible to know its server-side path using pydas. Out of curiosity, what's
>> your use case where you would want to know that information?
>>
>>  Thanks,
>>
>>  Zach
>>
>>
>>  On Wed, Oct 30, 2013 at 6:49 PM, BRIAN E CHAPMAN <Brian.Chapman at utah.edu
>> > wrote:
>>
>>>    Hello Midas World,
>>>
>>>  In 2012 Patrick posted the following code snippet to identify the
>>> location of a bitstream in the file system. Can the equivalent be done in
>>> pydas?
>>>
>>>  Mona,
>>>
>>> First, a bit about how items correspond to files. Items are made up of revisions. Most items contain one revision (the head or latest revision). Within each revision are bitstreams. These bitstreams are analogous to the files on the file system. With all that in mind, the following code should get you what you want (I'm going to assume the item ID is in a variable called, appropriately, $itemId.):
>>>
>>> // Load our models
>>> $ItemModel = MidasLoader::loadModel('Item');
>>> $ItemRevisionModel = MidasLoader::loadModel('ItemRevision');
>>> $BitstreamModel = MidasLoader::loadModel('Bitstream');
>>>
>>> // Get the item and its last revision from the time id
>>> $itemDao = $ItemModel->load($itemId);
>>> $lastRevisionDao = $ItemModel->getLastRevision($itemDao);
>>>
>>> // loop through the bitstreams and print their paths
>>> foreach($lastRevisionDao->getBitstreams() as $bitstreamDao)
>>>   {
>>>   print($bitstreamDao->getPath());
>>>   }
>>>
>>> Hope that helps!
>>>
>>> Thanks,
>>> Patrick Reynolds
>>> Technical Leader
>>> Kitware, Inc.919 869 8848
>>>
>>>
>>>  Brian E. Chapman, Ph.D.
>>> Associate Professor
>>> Department of Radiology
>>> University of Utah
>>>
>>>
>>>  _______________________________________________
>>> Midas mailing list
>>> Midas at public.kitware.com
>>> http://public.kitware.com/cgi-bin/mailman/listinfo/midas
>>>
>>>
>>
>>
>>  --
>> Zach Mullen
>> R & D Engineer
>> Kitware Inc.
>> 919-869-8858
>>
>> _______________________________________________
>> Midas mailing list
>> Midas at public.kitware.com
>> http://public.kitware.com/cgi-bin/mailman/listinfo/midas
>>
>>
>
>
> --
> +1 919 869 8849
>



-- 
Zach Mullen
R & D Engineer
Kitware Inc.
919-869-8858
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/midas/attachments/20131031/b5517b4a/attachment.html>