SAMP and HTTPS workaround?

[Mark Taylor]

Jean-Michel,

good to hear that we're looking at similar (possible) solutions.

I hadn't thought about the possibilities of extending this with
SAMP-specific VOTable content or filename conventions,
it's an interesting thought, though it would require a bit more
standardisation effort.

Encoding information in the filename or URL is problematic;
by the time the helper application gets to see the file,
it has typically been downloaded to a local temporary file by
the browser, so the filename may not match what was written
in the original HTML.

One relevant question: what Web SAMP capabilities do
data providers actually want or need that go beyond simply
sending a table/image from a web page to a local application?
I haven't come across these use cases, so if ASOV have 
examples I'd be very interested to hear.

Mark

On Sat, 24 Aug 2019, Jean-Michel GLORIAN wrote:

> Hi Mark and the SAMP users,
> 
> we had talked about this solution in the ASOV french meeting
> with all the difficulty that you mention.
> Thank you to have implementde a prototype helper application to test that.
> 
> 
> If people wants to add SAMP parameters in addition of the file ,
> maybe they could add them on the begin of the name of file
> using a convention and the helper application could parse the name.
> But yes it is quiet limited.
> 
> Or maybe we could use a Votable file with a SAMP data model
> with all the addition parameters and a link to the data fits file.
> The link would be static, dynamic and with or not a limited access  time
> 
> JMG
> 
> Le 22/08/2019 à 18:10, Mark Taylor a écrit :
> > Hi Doug,
> > 
> > thanks for registering an interest.  Any input on the topic welcome.
> > I guess the question I'd put related to the approach I'm suggesting
> > here is, how easy/hard would you expect it to be to encourage
> > WWT/CSC users to download and configure or use a helper application
> > along these lines?
> > 
> > My only other comment at this stage is it shouldn't make any difference
> > whether the URL points at a fixed file or represents a dynamic query.
> > 
> > Mark
> > 
> > On Thu, 22 Aug 2019, Burke, Douglas wrote:
> > 
> > > Mark,
> > > 
> > > I've been using your WebSAMP JS library [1] with our WWT interface to the
> > > Chandra Source Catalog - http://cxc.harvard.edu/csc2/wwt.html - to send
> > > URLs that return a votable or fits file when retrieved (ie the URL is
> > > actually a query and not to a file [2]). We are moving to https "soon" so
> > > I
> > > am interested in any possible solution (once the WWT client is moved over
> > > to https, that is).
> > > 
> > > Ta,
> > > Doug
> > > 
> > > [1] so thanks for that
> > > [2] thanks to a confluence of influences that aren't relevant here
> > > 
> > > 
> > > On Thu, Aug 22, 2019 at 9:05 AM Mark Taylor <M.B.Taylor at bristol.ac.uk>
> > > wrote:
> > > 
> > > > Dear SAMP users,
> > > > 
> > > > the problem of Web SAMP and HTTPS has been under discussion
> > > > for a while now - basically the Web Profile works fine with HTTP
> > > > but won't work from pages served using HTTPS.  A possible HTTPS-capable
> > > > profile has been prototyped, but it's pretty nasty.  There is much
> > > > more information on the topic here:
> > > > 
> > > >     http://andromeda.star.bristol.ac.uk/websamp/
> > > > 
> > > > As an alternative to the HTTPS profile, I'm thinking about more
> > > > lightweight workarounds.  One is just to provide a simple helper
> > > > application that takes a suitable filename on the command line
> > > > (VOTable table or FITS image) and sends it to a running SAMP
> > > > client.  Such an application could be associated in the
> > > > browser with suitable MIME types (application/x-votable+xml,
> > > > image/fits), or you could just choose it when the browser
> > > > asks you what application you want to open a downloaded file with.
> > > > 
> > > > This is much less flexible than allowing the web page (web application)
> > > > to interact with the SAMP hub itself, which is what you can do
> > > > with SAMP+Web Profile.  However, in practice, nearly(?) all Web SAMP
> > > > pages that I'm aware of just use Web SAMP to allow the user to
> > > > send a samp.load.votable or image.load.fits message, and that's
> > > > done nearly as well by the helper application.  It works with
> > > > rather than against normal browser operations, which makes it
> > > > much less painful to implement than the HTTPS profile;
> > > > it works equally with HTTPS or HTTP, and no additional
> > > > infrastructure is required.  The main downside is that the user has
> > > > to configure it somehow (install script, tell browser to use it
> > > > to handle relevant files).
> > > > 
> > > > I have written such a helper application, and I'd be interested
> > > > to know if anyone wants to try it out: especially data providers
> > > > who are using HTTPS and want to allow users to load tables/images
> > > > using SAMP.  Would this be an acceptable solution?
> > > > 
> > > > You can find the application here:
> > > > 
> > > >     http://andromeda.star.bris.ac.uk/websamp/sampload.jar
> > > > 
> > > > If you run, e.g. "java -jar sampload.jar /tmp/tmpfile.vot"
> > > > then it will pop up a window asking which VOTable-capable
> > > > SAMP client you want to send tmpfile.vot to.
> > > > (It works out what kind of file it is by looking at the content).
> > > > 
> > > > Unless your OS/browser can execute jar files directly, to use it with
> > > > a browser you'll need to accompany it with a small shell script or
> > > > equivalent like
> > > > 
> > > >     #!/bin/sh
> > > >     java -jar /path/to/sampload.jar "$@"
> > > > 
> > > > Any feedback, comments, ideas welcome.
> > > > 
> > > > Mark
> > > > 
> > > > --
> > > > Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
> > > > m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/
> > > > 
> > --
> > Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
> > m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/
> 
> 
> -- 
> 
> 
> ********************************
> Jean-Michel.Glorian at irap.omp.eu
> Jean-Michel Glorian - Responsable technique OV-GSO - Chef de projet CASSIS
> 
> IRAP - Institut de Recherche en Astrophysique et Planétologie,
> 9, avenue du Colonel Roche, BP 44346,
> 31028 Toulouse cedex 4
> (+33) 5 61 55 77 79
> http://cassis.irap.omp.eu
> 
> IRAP, Université de Toulouse, CNRS, CNES, UPS, (Toulouse), France
> ********************************
> 
> 

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/