America’s Economy

Alec Permison, ADIT/ASDPaul Milbourne, ADIT/ASDGustavo Torrico, ADEP/EPD

The Making of the Census Bureau’s First Official Mobile App

America’s Economy

Agenda• Overview

• Front-end Architecture

• Back-end Architecture

• Project Challenges

• Lessons Learned

America’s Economy

Overview• First Census Bureau mobile app

for Android/iOS both phone & tablet

• Developed as part of ongoing Web Transformation effort

• Displays 16 economic indicators

• 13 from Census Bureau Central Indicators Database Repository

• 2 from Bureau of Economic Analysis

• 1 from Bureau of Labor Statistics

America’s Economy

Overview• Collaborative team effort

• Communications Directorate – product owner & manager

• Contractor – front-end development

• Economics Directorate – data experts and back-end development

• IT Directorate – technical guidance, back-end development, and technical support

America’s Economy

Overview• Mobile app front-end displays data

• Three back-end API’s supply data at startup, refresh, and indicator release

• CIDR Private API developed by Econ

• BLS Private API developed by IT

• BEA Public API

• Config file on server queried at

startup

App

CIDR BLS BEA

BoC Private

America’s Economy

Front End Architecture• Adobe Flex 4.6

• Adobe AIR 3.3

• SWIZ 1.4

• iOS 4+

• Android 2.2+

America’s Economy

Front End Architecture

America’s Economy

Front End Architecture

America’s Economy

Front End Architecture

America’s Economy

Front End Architecture

America’s Economy

Front End ArchitecturePhone Core Tablet

• Skills Required

– ActionScript

– CSS

– XML

America’s Economy

Front End Architecture• Tools Required

– Adobe Flash Builder 4.6– Xcode and Eclipse for some

native components

• Pros of Adobe Flex

– Device agnostic from a single code base

– Easier than native development

– Broad developer community

• Cons of Adobe Flex

– Larger footprint (especially on iOS)

– Android support varies by device

– Slower performance

– Requires AIR runtime

America’s Economy

Front End Architecture

• LAMP stack:– RHEL 5.8

– Apache 2.2.3

– Mysql 5.0.95

– PHP 5.1.6

• Zend Framework 1.6– Simple, loosely-coupled

component library for web applications

• JSON-based :– Economic dashboard data

– Historical economic indicator data

– Simple format derived from mobile application mockups.

– Private through hash based “authentication”

– Text-based, easily parse-able.

– Data available as soon as upload process is completed on internal Census servers.

America’s Economy

Back End Architecture (CIDR)

category

display_cell

data_type

error_typegeo_level

time_slot

dashboard_data

America’s Economy

Back End Architecture (CIDR)

• JSON export of dashboard_data table

America’s Economy

Back End Architecture (CIDR)

• Historical data available in CIDR database (display_cell table)

America’s Economy

Back End Architecture (CIDR)

• Basic hash-key based authentication

• Example URL:

– http://www.census.gov/econ/currentdata/api/dashboard?id=sapient&hash=89704299208e7e9d16380e4384861396f3398cb0

• Calculating hash:

– sha1(secret key + time stamp + path requested)

1. Secret key – a 40 character alpha-numeric string

2. Time stamp – in the format YYYY-MM-DD 24HH (e.g. ‘2012-05-14 17’) using UTC timestamp.

3. Path requested – excluding id and hash parameters. ‘/econ/currentdata/api/dashboard’

America’s Economy

Back End Architecture (CIDR)

• Skills Required

– LAMP web dev

– Enterprise-scale development experience (not for newbie’s)

– REST interface design

America’s Economy

Back End Architecture• Tools Required

– Dev/test environment– IDE

• Pros of Private API

– Fast performance for database on our server

– Customized to need of front-end developer

– Access more data than public API

– Under your control

• Cons of Private API

– Additional skilled resources required

– Additional application to support

– Dependent on your infrastructure

America’s Economy

Back End Architecture

Project Challenges

• Limited insight into technical design and code at handoff (25,000+ LOC, few comments or technical docs initially)

• Security framework still under development

• Lack of dev/test tools & environment for mobile

• Standardizing data formats from 3 API’s (e.g. timestamps)

• Timely technical support from other agencies

• Coordination with external contractor (e.g. config updates)

America’s Economy

Lessons Learned

• Early involvement with contractor on technical design

• Schedule time for review and feedback at milestones

• Early engagement from security to address framework

• Identify and procure tools far in advance

• Test external API’s for reliability/accuracy

America’s Economy