[ome-devel] Existing client side code in C

[Ilya Goldberg]

On Aug 3, 2004, at 8:57 AM, Joshua Moore wrote:

> Two quick questions:
>
> (1) Are there client-side C bindings of the omeis methods available in 
> CVS?

omeis was designed to have the simplest most universal interface we 
could think of, so, lacking any imagination, we went with HTTP.  Any 
HTTP library (like libwww, or libcurl for C) can be used to talk to 
omeis.  For retrieval of data, the calls are simply GET requests with 
URL-encoded parameters (look at the curl examples here: 
http://docs.openmicroscopy.org.uk/api/omeis/synopsis.html).  So libcurl 
and sprintf is all you really need.  To send data to omeis (like 
writing pixels, etc) you need to be able to make POST requests.  
libcurl and libwww do this for you as well.  You know how you can 
upload files to some websites using your browser?  Now you know how to 
upload pixels to omeis.  In HTTP terms, its a multi-part form 
containing the binary data payload.

In principle, one could put together a real skinny layer on top of 
libwww or libcurl to hide the fact that you're just interacting with a 
web site, but that layer would be real skinny and not very exciting, so 
we never bothered.  Do you think one is necessary?

>
> (2) What is the availability of time information in the pixel struct? 
> I.e. if a user needs to calculate DX/DT over two images or 
> "timeElapsed=T*DT + startTime", is this available somewhere?

Timing is actually not very well dealt with, and my guess is it will 
probably be one of the first things in a schema update.  The time 
information would be done as a Semantic Type with Image granularity.  
In other words, it would be an Image attribute.  Probably the way to 
structure it for now would be to follow the lead of the plane 
statistics (src/xml/PlaneStatistics.ome).  There you have a plane index 
and some value associated with it.  If you store the dT for each plane, 
you can certainly calculate anything you need from that.

Since this will be of general interest, can I ask you to post your 
proposed ST(s) here for all of us to comment on?  We can then 
incorporate it into the core types and include it in the distribution 
and eventually migrate it into the OME XML schema proper.

-Ilya

>
> -Josh.
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