LinkedIn Mobile Search iPhone Architecture

Dennis Byrne

Agenda

● Model View Controller Pattern● Retrieval

o Core Datao Typeaheado Federated Search

● Cell construction & the Builder pattern● Metrics● Full Screen Scrolling● Unit Testing

The Model - “if you can’t see it”

● Think nouns, not verbs● LISearchV3Model.m

o SearchData.mo NSArrayo NSDictionary

● Ridiculously Good Looking

The View - “if you can see it”

● LISearchV3ViewController.xib● LISearchT1Cell.xib● LISearchT1CellHigh.xib● LISearchT1CellUltraHigh.xib● LISearchT2Cell.xib● LISearchT2CellHigh.xib● LISearchV2FilterButton.xib

The Controller● LISearchV3ViewController.m● Think verbs, not nouns● Delegate Pattern● Event Listeners● Glue code● Logic

MVC … try to think of it as VCM

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TM

Agenda

● Model View Controller Pattern● Retrieval

o Core Datao Typeaheado Federated Search

● Cell construction & the Builder pattern● Metrics● Full Screen Scrolling● Unit Testing

Retrieval Data Sources● Local Cache

o Core Datao SQLite

● Typeaheado phone-feo Typeahead Restli server

● Federated Searcho phone-feo Federated Search Restli server

Retrieval - Core Data

Retrieval - Remote Results

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Retrieval - Threading Model

● Everything is on the main thread● Except …

o Core Data retrievalo Core Data callbackso HTTP requests

Retrieval Controller

phone-fe

Agenda

● Model View Controller Pattern● Retrieval

o Core Datao Typeaheado Federated Search

● Cell construction & the Builder pattern● Metrics● Full Screen Scrolling● Unit Testing

Cell Construction - Builder Pattern

● LISearchV3UITableViewCellBuilder.m

Cell Builder

Retrieval Controller

phone-fe

Agenda

● Model View Controller Pattern● Retrieval

o Core Datao Typeaheado Federated Search

● Cell construction & the Builder pattern● Metrics● Full Screen Scrolling● Unit Testing

Metrics● LISearchV3Metrics.m● Page Views & Actions● Performance

o Firsto Secondo Thirdo Platform

iPhone android touch web

Cell Builder

Metrics LPTimer

Retrieval Controller

Perf

phone-fe

Agenda

● Model View Controller Pattern● Retrieval

o Core Datao Typeaheado Federated Search

● Cell construction & the Builder pattern● Metrics● Full Screen Scrolling● Unit Testing

Full Screen Scrolling

Cell Builder

Full ScreenScrolling

Metrics LPTimer

Retrieval Controller

Perf

phone-fe

Agenda

● Model View Controller Pattern● Retrieval

o Core Datao Typeaheado Federated Search

● Cell construction & the Builder pattern● Metrics● Full Screen Scrolling● Unit Testing

Unit Testing

● SenTestCase● LISearchV3JobScheduler

o LISearchV3ProductionJobScheduler.mo LISearchV3TestJobScheduler.m

● OCMock

SenTest … similar to JUnit < 4.0

-(void)setUp {}-(void)testSomething {

STAssertEquals(YES, NO, @"msg here");STAssertEqualsWithAccuracy(1.0, 1.2, 0.1, @””);STFail(@”msg here”);}

Dependency Injection

// similar to an interface in Java@protocol LISearchV3JobScheduler <NSObject>

- (void)enqueueOnMainThread:(void(^)())block;

@end

OCMock

#import "OCMock.h"

id op = [OCMockObject mockForClass:[LINetworkOperation class]];

NSDictionary *tag = @{@”key”: @”value”};

[(LINetworkOperation *)[[op stub] andReturnValue:OCMOCK_VALUE(tag)] tag];

Cell Builder

Full ScreenScrolling

Metrics LPTimer

Retrieval Controller

Perf

phone-fe

Job Scheduler

The Napkin Test

Agenda

● Model View Controller Pattern● Retrieval

o Core Datao Typeaheado Federated Search

● Cell construction & the Builder pattern● Metrics● Full Screen Scrolling● Unit Testing