Khang Toh describes his experience developing iOS apps and games since 2008. He had an idea for an app called Catstagram to share funny cat photos and videos after seeing cat pictures at work. This led him to co-found MogiMe to create mobile-first apps. The key challenge was resumable file uploads on mobile networks. He discovered the TUS protocol which allows splitting files into chunks for upload over HTTP. While still young, TUS provided a solution for his cat-focused startup and others through open source client and server implementations.

1. Khang Toh
@khangtoh

2. About me
• Developer, designer, thinker and entrepreneur
• Co-Founder / CTO at MogiMe Inc, San Francisco and
PicoCandy Singapore :)

3. My iOS
Story• Bought iPhone 1st gen in 2008. Started
playing with iphone sdk 2.0
• Developed first iOS game, smackBOTS
using UIKit !!??!!, 500K downloads in
the first month, Top100 Overall
• First PvP multiplayer iOS game, super
hackery implementation in 2009
• Partied with the Woz at WWDC2009
• Aspired to be an entrepreneur

4. What do you do as an
entrepreneur?

5. You think of ideas

6. You see funny cats
pics at work
Sometimes you get bored and
google for funny cats at work

7. Then all the sudden, you have an
awesome idea

8. Catstagram!
User Generated Funny Cat Pics
and Videos!
Shot using their mobile phone
camera!
Using the Catstagram app!

9. MVP Development 101
• Wrote server code
• Wrote iOS code
• Wrote server code
• Wrote iOS code

10. Problem
How to do file upload on mobile?

11. How to do file upload on mobile?

12. How to do file upload on mobile?

13. How to do file upload on mobile?
SUCKY SG MOBILE NETWORK

14. How to do RESUMABLE file
upload on mobile?

15. It's possible, but way too hard for a
mobile-first and cats-focus startup
• Flash?? Not possible + it sucks.
• HTML5 ?? Not great on mobile safari
• Native?? AFNetworking? HTTP?

16. Then you google like every developer

17. TUS.IO a resumable file upload
protocol on top of HTTP

18. What is the TUS protocol?
• Simple, open and free
• HTTP-based ( POST, HEAD, PATCH )
• Split file into chunks
• Send smaller pieces, server keeps track of
chunks / offset

19. What is the TUS protocol?
POST "/files" HTTP/1.1
Host: tus.example.org
Content-Length: 0
Final-Length: 100
RESPONSE:
HTTP/1.1 201 Created
Location: http://tus.example.org/files/1

20. What is the TUS protocol?
PATCH "/files/1" HTTP/1.1
Host: tus.example.org
Content-Length: 100
Offset: 0
[file data]
RESPONSE:
HTTP/1.1 200 Ok

21. What is the TUS protocol?
HEAD "/files/1" HTTP/1.1
Host: tus.example.org
RESPONSE:
HTTP/1.1 200 Ok
Offset: 70

22. What is the TUS protocol?
PATCH "/files/1" HTTP/1.1
Host: tus.example.org
Content-Length: 30
Offset: 70
[remaining file data]
RESPONSE:
HTTP/1.1 200 Ok

23. Awesome! What about the
servers and the clients?
• tusd - reference server implementation
using Go
• tus-ios-client, native objective-C client
library
• rubytus, ruby em-based server
implementation, work in progress

24. Use with caution
• Young protocol, 0.2.1, still changing
• New features in planning
• TUSKit - iOS client needs work, we're working
on it
• Need more support from OSS
• RFC? Not ready but is the goal for the
protocol
Probably ok for cat-focus mobile-first startups

25. Where to find more
info
• Official site http://tus.io
• Github: http://github.com/tus
• IRC: #tusio freenode
• Duh... It's open source

26. Demo

27. Questions?