1. RESTfull iOS with RestKit
Taras Kalapun

2. What is RestKit?
2

3. 3

4. RestKit is a RESTful Object Mapping Framework
for Cocoa
- (void)loadData {
RKObjectManager* objectManager = [RKObjectManager sharedManager];
RKObjectMapping* statusMapping = [objectManager.mappingProvider
objectMappingForKeyPath:@"status"];
[objectManager loadObjectsAtResourcePath:@"/status/user_timeline/RestKit"
objectMapping:statusMapping delegate:self];
}
- (void)objectLoader:(RKObjectLoader*)objectLoader didLoadObjects:(NSArray*)objects {
NSLog(@"Loaded statuses: %@", objects);
}
- (void)objectLoader:(RKObjectLoader*)objectLoader didFailWithError:(NSError*)error {
NSLog(@"Hit error: %@", error);
}
4

5. RestKit Architecture
• Network Layer
• Object Mapping
• Core Data
• Pluggable parsing layer
• Integration Points
5

6. Network Layer
6

7. Key Concepts
• RKClient - Your user agent
• Base URLs and Resource Paths
• RKRequest & RKResponse - The HTTP
lifecycle
• RKParams - Multi-part MIME requests
• Reachability - Detecting of ine/online status
7

8. Initializing RKClient
- (void)initRKClient {
// Initialize with a Base URL
RKClient* client = [RKClient clientWithBaseURL:@"http://restkit.org"];
// Setup HTTP AUTH
client.username = @"restkit";
client.password = @"rocks";
// Set an app-wide API key HTTP header
[client setValue:@"123456" forHTTPHeaderField:@"X-RESTKIT-API-KEY"];
// The first initialized RKClient becomes
// the sharedClient instance
[[RKClient sharedClient] isNetworkAvailable];
}
8

9. Sending Requests
- (void)sendRequest {
// Send an HTTP GET request to 'http://restkit.org/contacts'
[[RKClient sharedClient] get:@"/contacts" delegate:self];
}
// RKRequestDelegate methods
- (void)request:(RKRequest*)request didLoadResponse:(RKResponse*)response {
NSLog(@"Yay! We Got a response");
}
- (void)request:(RKRequest*)request didFailLoadWithError:(NSError*)error {
NSLog(@"Oh no! Error: %@", [error localizedDescription]);
}
9

10. Processing Responses
- (void)sendRequest {
// Send an HTTP GET request to 'http://restkit.org/contacts'
[[RKClient sharedClient] get:@"/contacts" delegate:self];
}
- (void)request:(RKRequest*)request didLoadResponse:(RKResponse*)response {
NSLog(@"Request Headers: %@", [response allHeaderFields]);
NSLog(@"Cookies: %@", [response cookies])
if ([response isSuccessful]) {
// Response status was 200..299
if ([response isCreated] && [response isJSON]) {
// Looks like we have a 201 response of type 'application/json'
NSLog(@"The JSON is %@", [response bodyAsJSON]);
}
} else if ([response isError]) {
// Response status was either 400..499 or 500..599
NSLog(@"HTTP error, status Code: %@", [response localizedStatusCodeString]);
}
}
10

11. Requests with Parameters
- (void)sendRequestWithParams {
// Simple params
NSDictionary* paramsDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
@"Taras Kalapun", @"name",
@"Ciklum", @"company", nil];
[[RKClient sharedClient] post:@"/contacts" params:paramsDictionary delegate:self];
// Multi-part params via RKParams
RKParams* params = [RKParams paramsWithDictionary:paramsDictionary];
NSData* imageData = UIImagePNGRepresentation([UIImage
imageNamed:@"picture.jpg"]);
[params setData:imageData MIMEType:@"image/png" forParam:@"photo"];
[params setFile:@"bio.txt" forParam:@"attachment"];
[[RKClient sharedClient] post:@"/contacts" params:params delegate:self];
}
11

12. Reachability
- (void)demoReachability {
// Check if the network is available
[[RKClient sharedClient] isNetworkAvailable];
// Register for changes in network availability
NSNotificationCenter* center = [NSNotificationCenter defaultCenter];
[center addObserver:self selector:@selector(reachabilityDidChange:)
name:RKReachabilityStateChangedNotification object:nil];
}
- (void)reachabilityDidChange:(NSNotification*)notification {
RKReachabilityObserver* observer = (RKReachabilityObserver*) [notification object];
RKReachabilityNetworkStatus status = [observer networkStatus];
if (RKReachabilityNotReachable == status) {
NSLog(@"No network access!");
} else if (RKReachabilityReachableViaWiFi == status) {
NSLog(@"Online via WiFi!");
} else if (RKReachabilityReachableViaWWAN == status) {
NSLog(@"Online via Edge or 3G!");
}
}
12

13. Object Mapping 2.0
13

14. Modeling a RESTful Service
"user": {
"id":31337,
"name":"Blake Watters",
"screen_name":"Blake Watters"
}
@interface RKTUser : NSObject
@property (nonatomic, retain) NSNumber* userID;
@property (nonatomic, retain) NSString* name;
@property (nonatomic, retain) NSString* screenName;
@end
14

15. "created_at":"Sat Mar 05 13:39:09 +0000 2011",
"favorited":false,
"id":44029179364253700,
"in_reply_to_screen_name":"JustJenFelice",
"text":"@JustJenFelice Be sure to join the Google Group and
reach out if you need any support!",
"user":{
"id":208727870,
"name":"RestKit",
"screen_name":"RestKit",
}
15

16. Initializing the Object Mapping
16

17. // Init RestKit
RKObjectManager* objectManager = [RKObjectManager
objectManagerWithBaseURL:@"http://twitter.com"];
// Setup our object mappings
RKObjectMapping* userMapping = [RKObjectMapping mappingForClass:[RKTUser
class]];
[userMapping mapKeyPath:@"id" toAttribute:@"userID"];
[userMapping mapKeyPath:@"screen_name" toAttribute:@"screenName"];
[userMapping mapAttributes:@"name", nil];
17

18. // Setup our object mappings
RKObjectMapping* statusMapping = [RKObjectMapping mappingForClass:[RKTStatus class]];
[statusMapping mapKeyPathsToAttributes:@"id", @"statusID",
@"created_at", @"createdAt",
@"text", @"text",
@"url", @"urlString",
@"in_reply_to_screen_name", @"inReplyToScreenName",
@"favorited", @"isFavorited",
nil];
[statusMapping mapRelationship:@"user" withObjectMapping:userMapping];
// Update date format so that we can parse Twitter dates properly
// Wed Sep 29 15:31:08 +0000 2010
[statusMapping.dateFormatStrings addObject:@"E MMM d HH:mm:ss Z y"];
// Register our mappings with the provider
[objectManager.mappingProvider setObjectMapping:userMapping forKeyPath:@"user"];
[objectManager.mappingProvider setObjectMapping:statusMapping forKeyPath:@"status"];
18

19. Loading Remote Objects
- (void)loadTimeline {
// Load the object model via RestKit
RKObjectManager* objectManager = [RKObjectManager sharedManager];
RKObjectMapping* statusMapping = nil;
// Twitter returns statuses as a naked array in JSON, so we instruct the loader to user the
appropriate object mapping
if ([objectManager.acceptMIMEType isEqualToString:RKMIMETypeJSON]) {
statusMapping = [objectManager.mappingProvider
objectMappingForKeyPath:@"status"];
}
[objectManager loadObjectsAtResourcePath:@"/status/user_timeline/RestKit"
objectMapping:statusMapping delegate:self];
}
- (void)objectLoader:(RKObjectLoader*)objectLoader didLoadObjects:(NSArray*)objects {
NSLog(@"Loaded statuses: %@", objects);
}
19

20. Con guring the Router
- (void)configureRouter {
[objectManager.router routeClass:[Contact class] toResourcePath:@"/contacts/(contactID)"];
[objectManager.router routeClass:[Contact class] toResourcePath:@"/contacts"
forMethod:RKRequestMethodPOST];
}
20

21. RESTful Object Manipulation
// Create a new Contact
- (void)createObject {
Contact* contact = [Contact new];
contact.name = @"RestKit User";
contact.email = @"user@restkit.org";
// POST to /contacts
[[RKObjectManager sharedManager] postObject:contact delegate:self];
}
// Edit Contact with ID 12345
- (void)editObject {
Contact* contact = [Contact new];
contact.contactID = [NSNumber numberWithInt:12345];
contact.name = @"New Name";
// POST to /contacts/12345
[[RKObjectManager sharedManager] putObject:contact delegate:self];
}
// Delete Contact with ID 321
- (void)deleteObject {
Contact* contact = [Contact new];
contact.contactID = [NSNumber numberWithInt:321];
// DELETE to /contacts/321
[[RKObjectManager sharedManager] deleteObject:contact delegate:self];
} 21

22. Core Data
22

23. Con guring CoreData
#import <RestKit/CoreData/CoreData.h>
- (void)configureObjectStore {
// Initialize the RestKit Object Manager
RKObjectManager* objectManager = [RKObjectManager objectManagerWithBaseURL:@"http://
restkit.org"];
// Initialize object store
// We are using the Core Data support, so we have initialized a managed object store backed
// with a SQLite database.
objectManager.objectStore = [RKManagedObjectStore
objectStoreWithStoreFilename:@"Contacts.sqlite"];
}
23

24. Mapping
RKManagedObjectMapping* userMapping = [RKManagedObjectMapping
mappingForEntityWithName:@"RKTUser"];
userMapping.primaryKeyAttribute = @"userID";
[userMapping mapKeyPath:@"id" toAttribute:@"userID"];
[userMapping mapKeyPath:@"screen_name" toAttribute:@"screenName"];
[userMapping mapAttributes:@"name", nil];
24

25. Working with Core Data
// Adapted from https://github.com/magicalpanda/MagicalRecord
// Get all the Contacts
NSArray* contacts = [Contact allObjects];
// Count the Contacts
NSError* error = nil;
NSUInteger count = [Contact count:&error];
// Find Contact by primary key
NSNumber* contactID = [NSNumber numberWithInt:12345];
Contact* somebody = [Contact objectWithPrimaryKeyValue:contactID];
// Find Contacts with criteria
NSPredicate* predicate = [NSPredicate predicateWithFormat:@"name contains[cd] 'restkit'"];
NSArray* matches = [Contact objectsWithPredicate:predicate];
25

26. Database Seeding
NSString *seedDatabaseName = nil;
NSString *databaseName = RKDefaultSeedDatabaseFileName;
objectManager.objectStore = [RKManagedObjectStore
objectStoreWithStoreFilename:databaseName usingSeedDatabaseName:seedDatabaseName
managedObjectModel:nil delegate:self];
RKManagedObjectSeeder* seeder = [RKManagedObjectSeeder
objectSeederWithObjectManager:objectManager];
// Seed DB with instances of RKTStatus from a snapshot of the RestKit Twitter timeline
[seeder seedObjectsFromFile:@"restkit.json" withObjectMapping:statusMapping];
// Seed DB with RKTUser objects. The class will be inferred via element registration
[seeder seedObjectsFromFiles:@"users.json", nil];
// Finalize the seeding and output a helpful informational message
[seeder finalizeSeedingAndExit];
26

27. Integration Points
Three20
Ruby on Rails
27

28. http://restkit.org/
http://twitter.com/restkit
http://github.com/RestKit/RestKit

29. ?
Taras Kalapun
iOS dev, Team lead, it-specialist
t.kalapun@gmail.com
Skype: t.kalapun