VisIVO Gateway and VisIVO Mobile for the Astrophysics Community - Science Gateways for Distributed Computing Infrastructures - page 181

The application allows the navigation through imported datasets and produced
images and scienti es users when requested visualizations are

available on the remote server for retrieve on their smartphones. Furthermore, it
allows sharing of data, images, and movies via e-mail or by exploiting popular
social networks. This provides a very handy way for scienti

c movies, and noti

c collaboration within

familiar interaction environments such as Facebook.
The VisIVO Mobile application con gures and submits workflows residing on

the VisIVO Science Gateway by means of the gUSE remote API. This API
interfaces to the core gUSE services without the WS-PGRADE user interface
component. Thus running and managing scienti

c workflows are realized by
command line solutions wrapped in shell scripts. The API exposes usage of gUSE
components through a simple web service interface, resulting in wide adaptability
by a diverse set of tools and programming languages.
VisIVO Mobile has been recently extended, integrating native WS-PGRADE/
gUSE utilities to create, con gure, and submit a workflow from scratch directly

from the application. The first implemented utility was the graph editor, which was

employed to create a workflow skeleton as depicted in Fig. 13.4 . Three other
functionalities are integrated from the native WS-PGRADE/gUSE core modules for
con

guring, submitting, and inspecting a running status of a workflow.
The VisIVO Mobile is implemented in Objective-C optimized for the Apple
iPad, and in the near future it will be ported to other popular smartphone devices. It
requires the connection to the VisIVO Science Gateway using a mobile broadband
network or a Wi-Fi connection. End-users can login with the same credentials as on
the gateway and the application provides the password coding in SHA cryptogra-
phy, exploiting the built-in functionalities of the Liferay environment and querying
the remote database to verify access credentials. The services are implemented
using HTTP, and the data are transferred using the JSON format, which is less
verbose than XML. This is a very critical choice as data are transferred through the
mobile network, which typically has a limited bandwidth.
An overview of the technology related to the VisIVO Mobile was discussed in
Sect. 13.2 . The mobile application connects to an HTTP web server to perform the
databases queries and the remote API calls are implemented in PHP.
The following code shows an example of the Remote API usage from a PHP
script. The WS-PGRADE workflow structure translated into an XML file ( work-

fl flow.xml) ) is submitted together with the input files and job binaries compressed into

a ZIP archive (inputs.zip). The file portmapping.txt contains all the key-value pairs

to identify the actual binaries and input files to the workflow jobs and input ports,

respectively. The variable $pwd contains the single authentication password for the
remote API usage.