Yes, hello everyone.

Hope you can hear me.

Loud and clear.

Perfect.

So this is a quick presentation on some web applications we developed in the context of

CTA at the Observatoire de Paris here.

And on next slide, I show the context, which is the primary design for CTA science portal.

And we were several teams around the world thinking that we really needed a modular design

with a core development, a science gateway core, and some common features like a top

menu bar to navigate between those different applications and a message bus to actually

exchange data between applications and also common authentication. So the web apps we developed at

the Observatoire de Paris are more about virtual observatory data access and distiller that is some

quick processing and a proposal handling platform to where observers can prepare their project for

observation and select the design they want for CTA and the configuration of the telescope

so that the science is really taken in the right way. So on next slide

I will just give a few hints that was the subtitle of my presentation but

at the Observatoire de Paris where we wanted to do it fast and clean and I will stress that

using frameworks is really what helped us to go fast on this and having just few people with some

experience with Django, Flask or Bottle while those Python frameworks differentiate the model,

view and the controller part of the web application and we actually use the three of them. This is

guided by the size and the requirement of the application but it's very simple. Flask has some

modules in addition and Django is really advanced with a database and model part that can be really

for advanced application. We use some jQuery and bootstrap code also and see that in the title

of jQuery for examples write less do more that's really the meaning of frameworks.

So, framework that are well maintained as those ones really accelerates the design and the

development. So, next slide I will show how it works. So, simply for the view that access

what we wanted is to have a simple form. So, this is for concert but we would have a

obscur search for those that know some observatory names and from the search you get the result table.

See that I stress here that we use a lot IVOA standards, ADQL which is a SQL kind of query for

for astronomy data, cone search in particular, obscur fields so this is standardized names of

columns and we can connect with other application with a protocol that is sound and also a pattern

to actually send job to a job cluster. So, on next slide I quickly develop this the flow of this

quite simple application you do a sort form and you get a result page. You may go to some

you may go to some configuration for quick analysis and you get the visualization and the result.

This is the web app. Aside of this we use a lot of standards and really modularity so the

tab server here is a different machine the UWS server is a different machine and between those

we speak a standard language. So, tab plus obscur plus ADQL that returns a view table.

The result can be sent to another application with a sound protocol. UWS request is also

standardized and it works and the result is a UWS job that is standardized. You also get

the provenance that is a new virtual observatory standard based on a W3C standard. So, W3C are

standard of the web and some other pattern of design. This really also accelerates the

development when you do a search form you don't have to specify how it will work to send the

request to the tab server. It's already standardized. So, on next slide.

I want to show just a different module. This is the tab server. It's actually based on a

well tested software that is DAX and we have some test data that is the HESS VL3 public data.

It is referenced in the VOR registry. So, maybe I'll come back to the previous slide

to show that there is a connection of the tab server to the VOR registry.

So, that this tab server is not used only by the web application. It's also open to any other

application that used the standard and this is an increased power of the application

using the standard. So, on next slide. Maybe the last one or the next one too.