CouchConf-SF-Developing-Native-iOS-Apps-with-Couchbase-Mobile

FOR iOSJens Al-e jens@couchbase.com

FOR LOLCATSJens Al-e jens@couchbase.com

I’M GOING TO TALK ABOUT…• The structure of Couchbase Mobile• How to build it into your iOS app• How to start it up & call it• Introduc=on to the CouchCocoa API 3

I’M ASSUMING…• You know a bit about CouchDB – Databases, Documents – Replica=on• You know a bit about Xcode and Objec=ve-‐C – Project build seLngs – Classes & methods 4

CLOUD vs. DESKTOP vs. MOBILE COUCHBASE TOPOLOGIES 5

“TRADITIONAL” USAGE: WEB APP STORAGE 6

“SORTA TRADITIONAL” USAGE: COUCHAPP 7

DESKTOP COUCHDB:UBUNTU / GNOME 8

COUCHBASE MOBILE:iPHONE / iPAD / ANDROID 9

COUCHBASE MOBILE: COUCH-‐IN-‐A-‐BOX• Reliable – 100% connec=vity to the database – Data available while oﬄine – Couchbase code is rev-‐locked to your app• Fast – No network lag or server load• Secure – Protected within app sandbox – Local-‐only TCP connec=on via loopback interface – No need to conﬁgure authen=ca=on 10

IMPLEMENTATION CHALLENGES ON iOS• No dynamic libraries – Solu=on: sta=c framework• Can’t spawn processes – Solu=on: Run Erlang & JavaScript in background thread• Very limited backgrounding – No syncing in background – No periodic maintenance tasks 11

WORK LOCALLY, SYNC GLOBALLY• The app has to work on the subway! – Local CouchDB database is your app’s persistent store – The UI displays & edits local documents• To sync, trigger replica=on – React to _changes by upda=ng UI, resolving conﬂicts• Sync when online, with the user’s permission – On launch or reac=va=on – When connec=vity changes – Give user control, e.g. manual mode – Consider using push no=ﬁca=ons 12

EMBEDDING COUCHBASE How to do it 13

INSTALLING THE FRAMEWORK• Download & unzip – hjp://ﬁles.couchbase.com/developer-‐previews/ mobile/iOS-‐Couchbase-‐developer-‐preview.zip• Put it somewhere – Inside your app’s folder – or in a shared loca=on 14

INSIDE THE FRAMEWORK Sta=c library (link with this) Run=me ﬁles (copy into app bundle) Basic API (#import this) 15

ADDING THE FRAMEWORK TO YOUR APP1. Drag2. Link 3. Copy (This stuﬀ is described in the README) 16

1. ADD FRAMEWORK TO PROJECT This is in the README! 17

2. ADD STDC++ LIBRARY TO TARGET This is in the README! 18

3. ADD BUILD PHASE This is in the README! 19

4. photo by ﬂickr user sashawolﬀ 20

5. START CODING#import <Couchbase/CouchbaseEmbeddedServer.h>@implementation DemoAppDelegate-‐ (BOOL) application: (UIApplication*)application didFinishLaunchingWithOptions: (NSDictionary*)launchOptions{ [CouchbaseEmbeddedServer start: self];}-‐ (void) couchbaseDidStart: (NSURL*)serverURL{ // Your code goes here!} 21

6. START CODING-‐ (void) couchbaseDidStart: (NSURL*)serverURL{ Jus tw r i te you r co de her e! ^_^ 22

OBJECTIVE-‐C APISThree ways to write your code 23

APPROACH #1: D.I.Y.• Save the server’s URL• Use Cocoa’s NSURLConnec=on*• Calling modes: – Synchronous – Asynchronous – Mul=threaded * 24

APPROACH #1: D.I.Y.• Pros: – No 3rd-‐party APIs to learn – No dependencies on 3rd party API code• Cons: – NSURLConnec=on can be awkward – Lots of code to write – You’ll need a JSON parser too – Synchronous mode can hurt responsiveness – Requires good knowledge of HTTP and CouchDB API 25

APPROACH #2: USE AN OBJECTIVE-‐C LIBRARY• Your choices: – CouchCocoa — Couchbase’s API in development hjps://github.com/couchbaselabs/CouchCocoa – Trundle hjps://github.com/TouchCode/trundle 26

APPROACH #2: USE AN OBJECTIVE-‐C LIBRARY• Pros: – Custom OOP API based on CouchDB model – Smaller, simpler code – Need less knowledge of CouchDB HTTP API• Cons: – Dependency on 3rd party library 27

APPROACH #3: HYBRID• Lots of iOS apps use UIWebView for some content• Easy to host a CouchApp in such a view – Just point UIWebView at the CouchApp’s URL – Changes made by CouchApp show up on _changes – Your changes show up on the CouchApp’s _changes – Syncing Just Works™ 28

APPROACH #3: HYBRID• Pros: – Web view is great for complex text layouts – Cross-‐plasorm development (standard Web stack) – Combines easily with na=ve code• Cons: – UIWebView is expensive – Can take work to get na=ve look & feel 29

COUCHCOCOA API 30

COUCHCOCOA LAYERS Your App Code Couchbase Mobile API REST API NSURLConnec=on 31

REST API 32

RESTResource• Represents an HTTP resource at a given URL• Forms hierarchies• Can remember state (eTag)• HTTP methods – GET:, PUT:, POST:, DELETE: – Easy to add query params & headers 33

RESTOpera`on• Represents an HTTP request/response• Created by a RESTResource• Basically asynchronous – Check state by geLng .isComplete – Add -‐onComple=on: block• …But can be used synchronously – Call -‐wait – Response proper=es will block =ll ready • .hjpStatus, .responseBody, etc. 34

USING RESTOpera`onRESTResource* server = [RESTResource resourceWithURL: serverURL];RESTOperation* op = [server GET];…Here a miracle occurs...?versionField.text = version; Returns immediately! 35

SYNCHRONOUS RESTOpera`onRESTResource* server = [RESTResource resourceWithURL: serverURL];RESTOperation* op = [server GET]; waits for a responseNSDictionary* stats = op.responseBody.fromJSON;NSString* version = [stats objectForKey: @"version"];versionField.text = version; 36

ASYNCHRONOUS RESTOpera`onRESTResource* server = [RESTResource resourceWithURL: serverURL];RESTOperation* op = [server GET]; code block* is scheduled to run later [op onCompletion: ^{ NSDictionary* stats = op.responseBody.fromJSON; NSString* version = [stats objectForKey: @"version"]; versionField.text = version;}]; execu=on con=nues without wai=ng! * 37

Couchbase API 38

COUCHBASE CLASSES:CONTAINMENT HIERARCHY CouchServer CouchDatabase CouchDatabase CouchDocument CouchDocument CouchQuery CouchQuery CouchRevision CouchRevision CouchQueryRow CouchQuery CouchAjachment CouchAjachment 39

CouchServer MAKES IT EASIERCouchServer* server = [CouchServer resourceWithURL: serverURL];NSString* version = server.version;versionField.text = version; 40

CRUD(Create, Read, Update, Delete) 41

CRUDCouchDatabase* db = [server databaseNamed: @"shopping"];[[db create] wait];CouchDocument* doc = [db untitledDocument];NSDictionary* item = [NSDictionary dictionaryWithObjectsAndKeys: @"Rutabagas", @"text", nil];[[doc putProperties: item] wait];NSString* ident = doc.documentID; 42

CRUDCouchDocument* doc = [db documentWithID: ident];NSDictionary* item = doc.properties;nameField.text = [item objectForKey: @"text"]; 43

CRUDNSMutableDictionary* item = [doc.properties mutableCopy];[item setObject: nameField.text forKey: @"text"];[[doc putProperties: item] start];[item release]; 44

CRUD[[doc DELETE] start]; 45

NOW YOU KNOW ABOUT…• The structure of Couchbase Mobile• How to build it into your iOS app• How to start it up & call it• Basics of the CouchCocoa API 46

★couchbase.org/get/couchbase-‐mobile-‐for-‐ios★github.com/couchbaselabs/iOS-‐Couchbase/★github.com/couchbaselabs/iOS-‐Couchbase-‐Demo/★github.com/couchbaselabs/CouchCocoa/ FINJens Al-ejens@couchbase.com 47

CouchConf-SF-Developing-Native-iOS-Apps-with-Couchbase-Mobile

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