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MAKING MEETUP

Matthew Bischoff (@mb) • Lickability Paul Bruneau (@ethicalpaul) • Meetup

THE HISTORY

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MEETUP 6.0

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THE GOAL COMPLETELY REDESIGN THE IOS EXPERIENCE OF MEETUP

REWRITE OR RE-SKIN?

WHY REWRITE? > Legacy Objective-C codebase > Completely new design > New APIs (v 3.0) > New team > Swift

HOW LONG?

HOW LONG? LONGER THAN WE THOUGHT

HOW LONG? LONGER THAN WE THOUGHT A FEW TIMES

WAS IT THE RIGHT CALL? WE THINK SO.

THE CODE

MacBookRetina:Meetup mb$ cloc . 1250 text files. 1202 unique files. 339 files ignored. http://cloc.sourceforge.net v 1.64 T=4.36 s (208.9 files/s, 21111.0 lines/s) ------------------------------------------------------------------------------- Language files blank comment code ------------------------------------------------------------------------------- Swift 771 20479 20124 48891 JSON 134 0 0 2194 Objective C 2 46 15 137 C/C++ Header 4 61 74 59 ------------------------------------------------------------------------------- SUM: 911 20586 20213 51281 -------------------------------------------------------------------------------

USE LIBRARIES BUT ISOLATE THEM

platform :ios, '9.0' source 'https://github.com/CocoaPods/Specs.git' use_frameworks! target 'Meetup' do pod 'RealmSwift', '~> 1.1.0' pod 'Alamofire', '~> 3.5.0' pod 'SocketRocket', '~> 0.5.0' pod 'SwiftyJSON', :git => 'https://github.com/Navdy/SwiftyJSON.git', :branch => 'xcode8b6' pod 'BuddyBuildSDK', '~> 1.0.12' pod 'RMStore', '~> 0.7' pod 'Static', git: 'https://github.com/venmo/Static.git' pod 'CLTokenInputView', '~> 2.3.0' pod 'KeychainAccess', '~> 2.4.0' pod 'XLForm', '~> 3.1.1' pod '1PasswordExtension', '~> 1.8' pod 'FormatterKit/TimeIntervalFormatter', '~> 1.8' pod 'Nuke', '~> 3.2.0' pod 'KVOController', '~> 1.1.0' pod 'BRYHTMLParser', '~> 2.1.0' pod 'AcknowList', :git => 'https://github.com/vtourraine/AcknowList.git', :branch => 'swift-2-3' pod 'ReachabilitySwift', '~> 2.4.0' pod 'NSAttributedString+CCLFormat', '~> 1.2.0' pod 'NYTPhotoViewer/Core', '~> 1.1.0' pod 'RSKGrowingTextView', '~> 1.2.0' pod 'Google/SignIn', '~> 2.0.3' pod 'FBSDKLoginKit', '~> 4.16' pod 'UIColor_Hex_Swift', :git => 'https://github.com/yeahdongcn/UIColor-Hex-Swift.git', :branch => 'Swift-2.3' pod 'DeepLinkKit', '~> 1.2.1' target 'MeetupTests' do inherit! :search_paths pod 'OHHTTPStubs', '~> 5.0.0' end end

KEY DEPENDENCIES > Persistence > RealmSwift > Networking > Alamofire > JSON Parsing > SwiftyJSON

PATTERNS > Storyboards, size classes, stack views, auto layout > private and final by default > Document anything internal or public > Protocols define interfaces > Dependencies are injected > Logic is unit tested (1403 tests)

TYPES MANY SMALL TYPES THAT DO FEW THINGS

MODEL HOLDS DATA AND MODELS BUSINESS LOGIC

/// Model representing a location where Meetups may take place. final class Location: Object { // MARK: - Public API /// The name of the city. dynamic var name = "" /// The full name of the city, as returned by query search, if applicable. dynamic var fullName: String? // MARK: - LocationGenerating var city: String { return name } /// The state which contains the city, if applicable. dynamic var state = "" /// The ISO_3166-1 country code for the country which contains the city. dynamic var country = "" /// Localized name of country based on request's language information. dynamic var localizedCountryName: String? /// The latitude of the city. dynamic var latitude: Double = kCLLocationCoordinate2DInvalid.latitude /// The longitude of the city. dynamic var longitude: Double = kCLLocationCoordinate2DInvalid.longitude /// The zip code of the city. For cities in countries without ZIP codes, a placeholder will be returned. dynamic var zipCode = "" } extension Location: NSCoding { … }

REQUEST DESCRIBES AN API REQUEST IN TERMS OF THE DOMAIN

/// An enum encapsulating types of location requests. enum LocationRequest: MeetupRequest { /// Request locations nearby a specified set of coordinates. case ByCoordinate(coordinate: CLLocationCoordinate2D, bearerToken: String?, pageSize: Int) /// Request locations corresponding to a queried city name or zip code. case ByQuery(query: String, bearerToken: String?) /// Request the authenticated or pre-registation user's current country. case Country(bearerToken: String?) // MARK: - MeetupRequest var path: String? { switch self { case .ByCoordinate, .ByQuery: return "find/locations" case .Country: return "members/self" } } var parameters: [String: AnyObject]? { switch self { case let ByCoordinate(coordinate, _, pageSize): return ["lat": coordinate.latitude, "lon": coordinate.longitude, "page": pageSize] case let ByQuery(query, _): return ["query": query] case .Country: return ["only": "country"] } } var URLRequest: NSURLRequest { if let bearerToken = bearerToken { return defaultRequestWithPreRegistrationAuthorizationHeader(bearerToken: bearerToken) } else { return defaultURLRequest() } } }

UPDATER MAKES A NETWORK REQUEST, PERSISTS INFORMATION, CALLS COMPLETION

/// Downloads objects related to nearby location requests. final class LocationUpdater { typealias Completion = (result: Result<[Location]>) -> Void /// The bearer token used to create authenticated requests. private let bearerToken: String? init(bearerToken: String? = nil) { self.bearerToken = bearerToken } func fetchLocationsNearby(coordinate: CLLocationCoordinate2D, pageSize: Int = 10, completion: Completion) { let request = LocationRequest.ByCoordinate(coordinate: coordinate, bearerToken: bearerToken, pageSize: pageSize) performLocationRequest(request, completion: completion) } func fetchLocationsMatchingQuery(query: String, completion: Completion) { let request = LocationRequest.ByQuery(query: query, bearerToken: bearerToken) performLocationRequest(request, completion: completion) } func fetchCountry(completion: (result: Result) -> Void) { let request = LocationRequest.Country(bearerToken: bearerToken) NetworkController.request(request).responseObject { (request, response, result: Result) in completion(result: result) } } private func performLocationRequest(locationRequest: LocationRequest, completion: Completion) { NetworkController.request(locationRequest).responseObject { (_, _, result: Result<[Location]>) in completion(result: result) } } }

PARSER TRANSFORMS JSON INTO MODELS

/// Parses a `Location` object from a JSON dictionary, or `nil` if no identifier is found. struct LocationParser: Parser { static func parse(dictionaryRepresentation: [String : AnyObject]) -> Location? { let JSONObject = JSON(dictionaryRepresentation) let location = Location() location.name = JSONObject["city"].stringValue location.fullName = JSONObject["name_string"].string location.localizedCountryName = JSONObject["localized_country_name"].string location.state = JSONObject["state"].stringValue location.country = JSONObject["country"].stringValue location.zipCode = JSONObject["zip"].stringValue if let latitude = JSONObject["lat"].double, longitude = JSONObject["lon"].double { location.latitude = latitude location.longitude = longitude } return location } } extension Location: Parseable { typealias ParserType = LocationParser }

VIEW MODEL MODELS ONLY THE VIEW NEEDS TO DISPLAY AND FORMAT

/// The view model containing all view-related data necessary to lay out an `LocationCell`. struct ViewModel { /// The configuration style for the cell based on a specified location status. enum LocationStatus { /// Cell configuration for an unknown location. case Unknown case Known(location: Location?, style: DisplayStyle) private var title: String { switch self { case .Unknown: return NSLocalizedString("Current location", comment: "…") case let .Known(_, style): return style.title } } private var image: UIImage { switch self { case .Unknown: return UIImage(named: "LocationServices")! case let .Known(_, style): return style.image } } } /// The location status for which to configure the cell. let locationStatus: LocationStatus }

DATA SOURCE TABLE AND COLLECTION VIEW DATA SOURCES AS SEPARATE OBJECTS

/// A data source object that acts as the table view data source for nearby locations, or optionally a loading interface. final class LocationDataSource : NSObject, UITableViewDataSource { /// An enum representing the table section. Do not initialize directly. Instead, call `sectionForSectionIndex`. enum Section { /// The section when a loading indicator is displayed. case Loading /// The section containing a cell displaying the user's current device location. case CurrentLocation(rows: [Meetup.LocationDataSource.CurrentLocationRow]) /// The section containing locations nearby the user's current location. case NearbyLocations(rows: [Meetup.LocationDataSource.LocationRow]) /// The number of rows in the section. var numberOfRows: Int { get } } typealias CellConfiguration = (tableView: UITableView, indexPath: NSIndexPath, section: Section, authorizationStatus: CLAuthorizationStatus?) -> UITableViewCell init(loading: Bool, cellConfiguration: CellConfiguration) func sectionForSectionIndex(index: Int) -> Meetup.LocationDataSource.Section? }

CELL CREATOR TAKES MODELS AND PRODUCES CELLS FOR THE DATA SOURCE

/// Sets up the table view and creates configured cells for location editing. final class LocationCellCreator { init(tableView: UITableView) { tableView.registerNibForClass(LoadingCell.self, reuseIdentifier: self.dynamicType.LoadingCellIdentifier) … } func cell(tableView: UITableView, indexPath: NSIndexPath, section: LocationDataSource.Section, authorizationStatus: CLAuthorizationStatus?) -> UITableViewCell { let cell: UITableViewCell? switch section { case .Loading: cell = loadingCell(tableView: tableView, indexPath: indexPath) } return cell } } // MARK: - Private methods private func currentLocationCell(tableView tableView: UITableView, indexPath: NSIndexPath, authorizationStatus: CLAuthorizationStatus?, location: Location?, isNearOtherLocations: Bool, isOnboarding: Bool) -> UITableViewCell { … } private func onboardingLocationCell(tableView tableView: UITableView, indexPath: NSIndexPath) -> UITableViewCell { … } }

WHAT WE LEARNED > The best way to learn Swift is to write a lot of it > Lack of refactoring makes architecture more important > Doing all-swift removed inter-op challenges > Swift 2.2 -> 2.3 migration went smoothly > Compile times are still terrible

AND FINALLY...

YOU CAN HIRE CAN HIRE YOU

THANK YOU WE’D LOVE TO ANSWER YOUR QUESTIONS — @MB AND @ETHICALPAUL