The document describes the design of iOS-Trello, an open-source iOS/Objective-C API wrapper for the Trello public API. It was created to enable collaborative planning and task management apps by providing a simple interface to the Trello API. The wrapper abstracts the API methods into objective-c classes and handles authentication, networking and JSON parsing to simplify making requests to the Trello API.

1. iOS-
Trello
Design of iOS-Trello
A general purpose, open-source,
iOS/Objective-C API Wrapper
for the Trello Public API
Vince Mansel
http://slideshare.net/VinceMansel/iostrellotalk2

2. About …
Experience
 Software Developer
 Networking Consultant
 Systems Engineer
Past companies/clients
 Juniper, Cyan, Calix, Minerva, DirecTV, Divicom, Network
Solutions, PacBell, AT&T Bell Labs
Education: MSEE - Georgia Tech, BSEE – Purdue
Fun: music, salsa, travel, hiking, AC, …

3. 3
Agenda
 Drivers
 Big Picture
 Decision Funnel
 Baseline Solution
 Software Architecture
 Questions
 Extra:
 Code Samples, Software Design and Techniques
 http://slideshare.net/VinceMansel/iostrellotalk2
@vincemansel Designing iOS-Trello

4. Driver #1: ShowPlan 4
(iOS Client)
Production Design,
Planning and Reference
For Creative People
#1 Feature:
ARRANGING
&
SEQUENCING
@vincemansel Designing iOS-Trello

5. Driver #2: Trello 5
(web client)
Collaboration and
Task Management
Web Service
(clients available on web, iPhone,
Android, etc)
#1 Feature:
CLOUD
COLLABORATION
@vincemansel Designing iOS-Trello

6. 6
Big Picture(s)
 What is the problem that we are solving?
a. Social: Bridge idea/design with real-time performance
b. Technical: Allow users to share ideas with a mobile client to
other clients connected via web services
 How can we create a system/tool to transform creative ideas
into sharable plans between collaborators?
@vincemansel Designing iOS-Trello

7. 7
Decision Funnel
Specific: Create a collaborative presence for the App
Use a “reflective” web service with an API
General: Allow developers to write collaborative apps
 Open-source
Create an API Wrapper
 Simple, Object-Oriented, Modular
 Fast & Lightweight
 Easy to implement & maintain
@vincemansel Designing iOS-Trello

8. 8
Baseline Solution
API Wrapper iOS-Trello API
ShowPlan: iOS-Trello: Trello:
A Production An open-source A collaboration
Design app API Wrapper and task management
implementation web service
A customized iOS
Trello Client
https://github.com/vincemansel/ios-trello
@vincemansel Designing iOS-Trello

9. 9
Object Mapping
ShowPlan -> Trello
 ShowFlow -> Board
 Scene -> List
 Element -> Card
First Iteration
 Export only
 Text Only
@vincemansel Designing iOS-Trello

10. 10
ios-trello app architecture
Application Code
ios-trello
OAuth AFNetworking
NSURLRequest NSURLConnection NSURLResponse
@vincemansel Designing iOS-Trello

11. 11
ios-trello internals
[VMTrelloApiClient sharedSession]
SINGLETON
management
connection
credential
storage
Notification
Checklist
Member
Action
Board
Type
Card
List
WRAPPERS
…
(Objective-C
Categories)
MACROS
@vincemansel Designing iOS-Trello

12. 12
Collaboration: Today
Text
Email
@vincemansel Designing iOS-Trello

13. 13
Collaboration: Next Iteration
Multimedia
Pe
e rt
Email o
Pe
er
@vincemansel Designing iOS-Trello

14. Questions?

15. Thanks!
@vincemansel
@ShowPlanApp
facebook.com/ShowPlan

16. 16
Future for ios-trello
Iterate
Develop and test additional API calls in phases
Architect and develop real-time, bi-directional
functionality
Expand documentation and use cases
@vincemansel Designing iOS-Trello

17. 17
Trello Public API
https://trello.com/docs/api/index.html
@vincemansel Designing iOS-Trello

18. 18
trello.com/docs/api
@vincemansel Designing iOS-Trello

19. 19
Use Case: Create a Trello Board
a. User touches “Create Board” button on View
b. Controller instantiates a popover with text entry UI
c. User enters some text and touches OK
d. Popover sends text as a message to its delegate (Controller)
e. Delegate transforms text to a board name, and sends the name
parameter to the POST /1/boards Wrapper
f. JSON is asynchronously returned to caller and parsed for name
and ID of the created board
g. Caller stores board ID in Model and writes “boardName” to a
tableView cell.
@vincemansel Designing iOS-Trello

20. Delegate: send + JSON parse 20
@vincemansel Designing iOS-Trello

21. 21
WRAPPER
@vincemansel Designing iOS-Trello

22. 22
MACROS
@vincemansel Designing iOS-Trello

23. 23
Design Approach
Choose specific APIs calls and parameters required for
current revision of App
Construct API calls in desktop browser
Reverse Engineer & Inspect API behavior (JSON) and
network interaction (HTTP)
Code direct API calls in Objective-C
Abstract API methods into Wrapper classes
Test and iterate
@vincemansel Designing iOS-Trello

24. 24
Create the WRAPPER
https://trello.com/1/members/me?
notifications=all&notifications_limit=5&organizations=all&organization_paid_
account=true&organization_fields=name
https://trello.com/1/members/me REQUEST
?
notifications=all
&notifications_limit=5
&organizations=all
&organization_paid_account=true PARAMETERS
&organization_fields=name
@vincemansel Designing iOS-Trello

25. 25
Additional WRAPPERS
GET
POST
PUT
DELETE
@vincemansel Designing iOS-Trello

26. 26
Resources
Contribute to the ios-trello project
 https://github.com/vincemansel/ios-trello
Follow the Trello API development
 https://trello.com/api
@vincemansel Designing iOS-Trello

27. 27
REST
 Client-Server
 ShowPlan < > trello.com
 Stateless
 CoreData store in ShowPlan
 Cacheable
 (Client-side) JSON sent back in response to request
 Layered System
 Server-side implementation
 Code on demand (optional)
 NA
 Uniform Interface
 API, JSON, URIs (board, list, card, member)
@vincemansel Designing iOS-Trello

28. 28
REST Resources
RESTKit (iOS)
 https://github.com/RestKit/RestKit
RESTful API Server – Doing it the right way
 http://blog.mugunthkumar.com/
REST API Design Rulebook (Mark Messe)
@vincemansel Designing iOS-Trello

29. The Target
Ideas Implementation
Plans Performance
Design Phase Development
Writers Actors
Directors Performers
Planners Developers
Designers Implementers
Architects

30. 30
“The” Answer, extended
API Wrapper iOS-Trello API
ShowPlan: iOS-Trello: Trello:
A customized iOS An open-source A collaboration
Trello Client API Wrapper and task management
implementation web service
API Wrapper
ios4trello:
The demo project
for API Wrapper
dev and test
@vincemansel Designing iOS-Trello

31. 31
ios4trello (demo test app)
API Wrapper Sandbox:
Exercise, test and explore
Manual test tool
Open-source
Extensible
http://showplan.net/ios4TrelloAtGithub
http://bit.ly/ios4trello
https://github.com/vincemansel/ios-trello
@vincemansel Designing iOS-Trello

32. The Trello Tech Stack 32
Source:
http://blog.fogcreek.com/the-trello-tech-stack/
@vincemansel Designing iOS-Trello