Talking about developing backends and connecting to them from mobile apps.

1. Nacef LABIDIConnect your app to your backend
Connect your mobile app to your
backend
Presented by Nacef LABIDI
March 2014

2. Who I am ?
• System Level Developer @ STMicroelectronics
• Co-founder and Technical Manager @ Oceanys
• Project Manager @ Evatys
• Technical Consultant @ Hewlett-Packard
• IT Manager @ US Peace Corps
• Global Helpdesk Manager @ Vistaprint

3. Who I really am ? ;)
• Computer engineer, geek and music addict.
• Open Source enthusiast, supporter and contributor.
• Android apps developer (when I find some time)
• Python fan and supporter.
• Speak many programming languages.

4. Audience
• Beginners in Android development
• People wanting to build mobile apps around dynamic
content
• Building multi-platform mobile apps

5. Storing your data inside vs. outside of your
app
Pros
• Decoupling between the app and the data
• Keeping the logic on the server side
• Makes your apps lighter
• Makes your logic consistent and reusable
• Evolution of your service relies more on the data than
the app itself.
• Publish your data to multiple medias : Website, all kind
of mobile devices, share your data with affiliates

6. Storing your data inside vs. outside of your
app
Cons
• Need to be connected to access the data
• This can be improved by caching some of the data
locally
• Delays in treatment depending on the volume of data
and the quality of the connection
• May expose your data to some security risks
• Again this can be addressed

7. How would I proceed ?
If you don’t have a backend, start by building one
• This will help you define the structure of the data that
you want to expose in your app
• Designing the data will also help you design the layout
of your app
• Build a webservice API that will be used to access the
data
• Secure your webservice

8. Building your backend
Choose the right tools : modern frameworks
• Define your data structures
• Use migrations to evolve your data structures without
messing with your data
• Use RESTful capabilities of your framework to publish
your data to your app
• Choose the exchange format that suits you most
(XML, JSON…)
• Use security capabilities to protect your data

9. Secure your backend
Different security methods :
HTTP Basic Authentication
Login and password sent with the HTTP request
ApiKey Authentication
Passing an ApiKey generated on the server side in each
HTTP request
OAuth Authentication
Through a third party authentication service (Google,
Facebook, Yahoo, OpenID …)
Create your custom authentication system
Public/Private RSA keys
…

10. My personal choices
Python language
• http://www.python.org
Django framework https://www.djangoproject.com
• Provides Model classes
• Supports many DB backends (Relational & NoSQL)
• Migrations: through South module
http://south.aeracode.org
• RESTful API: through Tastypie module
http://tastypieapi.org

11. Build your app
Use Apache HTTP Client classes
Use Google Gson to map API responses to your
local objects
• https://code.google.com/p/google-gson
Use AsyncTask to keep your app responsive while
retrieving your data from the server
Goodies : You should try RoboGuice to have a nicely
architected app
• https://github.com/roboguice/roboguice

12. Retrospective
Tunibus : An android app allowing users to find their
way through the Tunis public transportation (Bus,
Metro, Train …)
Neo4j Graph database representing stations and
edges representing transportation lines connecting the
stations. http://www.neo4j.org
RESTful webservice that returns the possible paths
between two points
Android app that connects through the API to the
Graph DB
Crowdsourcing web app to enhance the data quality

13. Retrospective
RESTful
API

14. Thank you !
Questions ?