Writing Mobile Applications with

CouchbaseKnoxville Cocoaheads

March 2016

Who is this guy?• Mike Hagedorn

• Language Polyglot

Why Couchbase?

Changing face of IT DemandsHAScalableAgile, Schemaless

CB: Synching, Admin GUI, SDKs

Couchbase History

Couchbase Terms• Node

• Cluster

• Bucket

• Document

• View

Couchbase Components

Mobile embedded local db with syncGw internet facing componentServer: Ent grade nosql db

Couchbase Server

Couchbase LiteCouchbase Lite is an embedded JSON database that can work standalone, in a P2P network, or as a remote endpoint for Couchbase Server.

EmbeddedAll IO is localSyncs are transparent in backgroundDisconnected operationNO PUSHNO Network

CBL

Device 1

CBL

Device 2

CB Server

Cluster 1with GW!

Sync Gateway

CBL

Device 1

CBL

Device 2

CB Server

Cluster 1

Data Needed Here!

?

Remote Data Center

SGW

Couchbase Model

• An object oriented wrapper on top of CBLDocument

• Somewhat like NSManagedObject

Couchbase Challenges

• Complicated Queries are Hard

• Views!

Getting Started

• DL Couchbase Lite Framework

• Add CouchbaseLite.framework to your project

• There is no step 3

Initialization

//AppDelegate CBLManager *manager = [CBLManager sharedInstance]; NSError *error; self.database = [manager databaseNamed:kDBName error: &error]; if (error) { NSLog(@"error getting database %@",error);

exit(-1); }

DatabaseRockets

Name Weight Diameter Cd

alpha 29 25 0.75

hawk 35 30 0.8

Document

{ "coefficientFriction": 0.75, "diameter": 25, "name": "alpha110", "type": "rocket", "weight": 23 }

# Bb6YvfoCH7NIgsVDtgjE7O

Unique IDMay contain binary attachments

Database View

//RootController or CBModel //Define a view that only returns documents of type ‘kRocketDocType’ CBLView* view = [db viewNamed: @"rockets"];

if (!view.mapBlock) { // Register the map function, the first time we access the view: [view setMapBlock: MAPBLOCK({ if ([doc[@"type"] isEqualToString:kRocketDocType]) emit(doc[@"name"], nil); }) reduceBlock: nil version: @"1"]; }

Map/ReduceCalled on every documentOptional Reduce

Using Views in your UI

// Create a query showing rockets: CBLLiveQuery* query = [[[database viewNamed:@"rockets"] query] asLiveQuery];

// Plug the query into the CBLUITableSource, which will use it to drive the table.

// (The CBLUITableSource uses KVO to observe the query's .rows

self.dataSource.query = query;self.dataSource.labelProperty = @"name";

// Assumes something like this in your controller

@property (nonatomic) IBOutlet UITableView* tableView;

@property (nonatomic) IBOutlet CBLUITableSource* dataSource;

Customizing Table Cells- (void)couchTableSource:(CBLUITableSource*)source willUseCell:(UITableViewCell*)cell forRow:(CBLQueryRow*)row

// Set the cell background and font:

// Configure the cell contents. Map function (above) copies the doc properties into its value, so we can read them without having to load the document.

NSDictionary* rowValue = row.value;BOOL checked = [rowValue[@"check"] boolValue];

if (checked) { cell.textLabel.textColor = [UIColor grayColor];

cell.imageView.image = [UIImage imageNamed:@"checked"]; } else { cell.textLabel.textColor = [UIColor blackColor]; cell.imageView.image = [UIImage imageNamed: @"unchecked"]; }

// cell.textLabel.text is already set, thanks to setting up labelProperty }

Selecting A Row

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { NSLog(@"didSelectRowAtIndexPath"); NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow]; CBLQueryRow *row = [self.dataSource rowAtIndex:indexPath.row]; ASDRocket* rocket = [ASDRocket modelForDocument: row.document];

// Do something with rocket… }

Adding Items- (IBAction) insertNewObject: (id)sender {

ASDRocket* rocket = [ASDRocket modelForNewDocumentInDatabase:self.database];

rocket.name=name; rocket.weight = 23.0; NSError* error; if (![rocket save: &error]) { return nil; } NSLog(@"Rocket Created");

}

Deleting Items-(void) tableView:(UITableView*)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath{ if (editingStyle == UITableViewCellEditingStyleDelete){ CBLQueryRow *row = [self.dataSource rowAtIndex:indexPath.row]; ASDRocket* rocket = [ASDRocket modelForDocument: row.document]; NSError* error; if (![rocket deleteDocument: &error]){ NSLog(@"Unable to delete Rocket"); return; } [self.tableView reloadData]; }

}

Replications CBLReplication *pull; CBLReplication *push; h; pull = [_database createPullReplication:_remoteURL]; pull.continuous = YES; pull.network = @"WiFi";

push = [_database createPushReplication:_remoteURL]; push.continuous = YES; pull.network = @"WiFi";

[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(replicationProgress:) name:kCBLReplicationChangeNotification push];

[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(replicationProgress:) name:kCBLReplicationChangeNotification pull];

CBLModel• Maps Objects to documents

@interface ASDRocket : CBLModel

+ (NSString*) docType;

@property (strong) NSString *name; @property (assign) double diameter; @property (assign) double weight; @property (assign) double coefficientFriction;

/** Returns a query for all the rockets in a database. */ + (CBLQuery*) queryRocketsInDatabase: (CBLDatabase*)db;

/** Returns a query for all the rockets with name in a database */ + (CBLQuery*) findInDatabase:(CBLDatabase*)db byName:(NSString *)name;

@end

CBLModel• No types in documents

• convention is to use type field

• Map functions can pick out docs with the right type

if (doc.type == “rocket”){

emit(doc.created, doc.text)

};

Demo

• https://github.com/mwhagedorn/couchbase_ios_rockettown

• https://github.com/mwhagedorn/couchbase_osx_rockettown

• Two platforms synching to one database

Questions?

• @mwhagedorn