Developing MyTrafficCam

Sharing of how I build a web service for monitoring traffic condition in Malaysia-Singapore border. A community project by HackerspaceJB, in Johor Bahru.

Transcript

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