The document discusses the development of MyTrafficCam, a service that shows traffic conditions for travelers between Johor Bahru and Singapore by aggregating feeds from various camera sources. It covers technical aspects like the software stack, API definitions, and challenges related to system design and bandwidth. The authors report growth in visitors and highlight ongoing issues with camera availability and operational costs.

1. Developing MyTrafficCam
Leong Hean Hong
#HackerspaceJB #HSJB

2. About
● MTC shows traffic condition for JB-SG
travellers
● MTC aggregates cameras from different
sources
● I talk about how it works
● Share collected data
● Describe some of the challenges

3. System Design
Sponsor: JLP Technologies

4. System Design
● Camera sources
○ LTA (Singapore)
○ LLM (Malaysia)
○ Own camera @ Menara Cyberport
● Providing feed to
○ Mobile clients (iOS + Android)
○ Partner’s website
Sponsor: Common Extract

5. Components In Web Service
Sponsor: Hongineer

6. Software Stack
● CentOS
● Apache
● PHP 5.2
○ GluePHP (micro-framework)
○ Twig Templating library
Sponsor: Property.cc

7. Development Tools
● Sublime Text
○ Programming editor
● Filezilla
○ For deployment on production server
● Git
○ Source control
● Bitbucket
○ Free private repo
○ Code backup

8. Defining API
● Client makes request via HTTP
● Response in JSON
● API specifications documented in Google
Doc
○ Establish standardization across team

9. Defining API

10. CodeFu Techniques

11. Time-sensitive Photo
public static function photoURL($camId) {
$time = time();
return "/photo/{$camId}/{$time}/".self::genHash($camId, $time);
}
Add timestamp to photo URL, expires in 5
seconds

12. Tie Photo To Client’s IP
public static function photoURL($camId) {
return strtr('http://:host/v1api/photo/:camId/:hash', array(
':host' => $_SERVER['HTTP_HOST'],
':camId' => $camId,
':hash' => self::photoHash($camId)
));
}
protected static function photoHash($camId) {
return sha1(self::HASH_KEY.$camId.$_SERVER['REMOTE_ADDR']);
}
Prevent reuse of photo across devices

13. Rate-limiting Control
● Log IP address
● Allow not more than 10 requests per second
per IP
○ Currently we have only 6 cameras

14. Analytics
Growing from 6K
to 8K visitors
Busy night...

15. Analytics
More traffic in Sat/Sun

16. Challenges

17. ● LLM Camera down frequently
● Need more cameras
● Cost of running MTC
Challenges

18. Running Out Of Bandwidth
18.50 GB in July 2014
1.73 GB from single host

19. Feedback
support@mytrafficcam.com