Launch Darkly

Tested with Launch Darkly version 9.12.0 (iOS)

Using Appfigurate remote properties instead of Launch Darkly flag evaluation APIs directly allows for the following:

• locally change Launch Darkly flags without affecting your entire customer base.

• compile time type safety - Appfigurate remote properties are typed.

• avoids hardcoding duplicated flag names throughout your app.

• avoids hardcoding duplicated default values throughout your app.

• deleting a flag from Launch Darkly Console won't affect existing apps, they'll continue to use the default value provided in the reset method.

We assume you already have Appfigurate Library and Launch Darkly integrated into your app with the following example remote properties created in the Launch Darkly console:

Add remote properties into your Configuration subclass

Update your configuration subclass to include your remote configuration properties. Provide default values for the properties in the overridden reset method. See also Supported property types.

Swift

Swift Configuration example

import Foundation
import AppfigurateLibrary

@objcMembers class MyConfiguration: APLConfiguration {
...
    @RemoteBoolProperty(key: "alwaysDarkMode", description: "Force dark mode to be always set")
    var alwaysDarkMode: Bool

    @RemoteStringPropertyEdit(key: "appTitle", description: "Title of application")
    var appTitle: String

    @RemoteIntPropertyEdit(key: "bookingDuration", description: "Duration (days) for reservation bookings")
    var bookingDuration: Int

    @RemoteDoublePropertyEdit(key: "fontSize", description: "Size of font throughout app")
    var fontSize: Double
...
    override func reset() {
        alwaysDarkMode = false
        appTitle = "Holiday finder"
        bookingDuration = 30
        fontSize = 13.0
    }
...
}

Objective-C

Objective-C Configuration header example

@import Foundation;
@import AppfigurateLibrary;

@interface MyConfiguration : APLConfiguration
...
@property(nonatomic, assign) BOOL alwaysDarkMode;
@property(nonatomic, strong) NSString* appTitle;
@property(nonatomic, assign) NSInteger bookingDuration;
@property(nonatomic, assign) double fontSize;
...
@end

Objective-C Configuration implementation example

#import "MyConfiguration.h"

@implementation MyConfiguration
...
REMOTE_BOOL_PROPERTY(alwaysDarkMode, @"alwaysDarkMode", @"Force dark mode to be always set");
REMOTE_STRING_PROPERTY_EDIT(appTitle, @"appTitle", @"Title of application");
REMOTE_INT_PROPERTY_EDIT(bookingDuration, @"bookingDuration", @"Duration (days) for reservation bookings");
REMOTE_DOUBLE_PROPERTY_EDIT(fontSize, @"fontSize", @"Size of font throughout app");
...
- (void) reset {
    self.alwaysDarkMode = NO;
    self.appTitle = @"Holiday finder";
    self.bookingDuration = 30;
    self.fontSize = 13.0;
}
...
@end

Provide remote configuration values to Appfigurate Library when requested

Appfigurate Library needs to be able to read the current remote flags from Launch Darkly. Copy and paste the following code into your app.

Swift

Swift example

APLFetchRemoteConfiguration { propertyKey, propertyType, defaultValue in
    if propertyType == .bool {
        return NSNumber(value: (LDClient.get()!.boolVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).boolValue)))
    } else if propertyType == .int {
        return NSNumber(value: (LDClient.get()!.intVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).intValue)))
    } else if propertyType == .double {
        return NSNumber(value: (LDClient.get()!.doubleVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).doubleValue)))
    } else { // .string 
        return NSString(string: LDClient.get()!.stringVariation(forKey: propertyKey, defaultValue: (defaultValue as! String)))
    }
}

Objective-C

Objective-C example

APLFetchRemoteConfiguration(^NSObject* (NSString* propertyKey, APLRemotePropertyType propertyType, NSObject* defaultValue) {
    if (propertyType == APLRemotePropertyTypeBool) {
        return [NSNumber numberWithBool: [[LDClient get] boolVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) boolValue]]];
    } else if (propertyType == APLRemotePropertyTypeInt) {
        return [NSNumber numberWithInteger: [[LDClient get] integerVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) integerValue]]];
    } else if (propertyType == APLRemotePropertyTypeDouble) {
        return [NSNumber numberWithDouble: [[LDClient get] doubleVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) doubleValue]]];
    } else { // APLRemotePropertyTypeString 
        return [[LDClient get] stringVariationForKey: propertyKey defaultValue: (NSString*) defaultValue];
    }
});

Notify Appfigurate Library when Launch Darkly has received flags

We need to tell Appfigurate Library that Launch Darkly has received flags, so that it can keep your Configuration subclasses remote properties in sync.

Swift

Add a call to APLFlushRemoteConfiguration in any existing Launch Darkly start(config, startWaitSeconds, completion) and observeAll(owner, handler) blocks.

Swift example

LDClient.start(config: config, startWaitSeconds: 5.0) { timedOut in
    ...
    APLFlushRemoteConfiguration() // add this line
}
...
LDClient.get()?.observeAll(owner: self) { keys in
    ...
    APLFlushRemoteConfiguration() // add this line
}

Objective-C

Add a call to APLFlushRemoteConfiguration in any existing Launch Darkly startWithConfiguration:startWaitSeconds:completion: and observeAllKeysWithOwner:handler: blocks.

Objective-C example

[LDClient startWithConfiguration:config startWaitSeconds:5.0 completion:^(bool timedOut) {
    ...
    APLFlushRemoteConfiguration(); // add this line
}];
...
[[LDClient get] observeAllKeysWithOwner: self handler:^(NSDictionary<NSString *,LDChangedFlag *> *handler) {
    ...
    APLFlushRemoteConfiguration(); // add this line
}];

Complete initialisation example

Swift

Swift complete initialisation example

let config = LDConfig(mobileKey: "<YOUR-KEY>", autoEnvAttributes: .enabled)

// add this block of code
APLFetchRemoteConfiguration { propertyKey, propertyType, defaultValue in
    if propertyType == .bool {
        return NSNumber(value: (LDClient.get()!.boolVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).boolValue)))
    } else if propertyType == .int {
        return NSNumber(value: (LDClient.get()!.intVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).intValue)))
    } else if propertyType == .double {
        return NSNumber(value: (LDClient.get()!.doubleVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).doubleValue)))
    } else {
        return NSString(string: LDClient.get()!.stringVariation(forKey: propertyKey, defaultValue: (defaultValue as! String)))
    }
}

LDClient.start(config: config, startWaitSeconds: 5.0) { timedOut in
    if !timedOut {
        APLFlushRemoteConfiguration() // add this line
    }
}
LDClient.get()?.observeAll(owner: self) { keys in
    APLFlushRemoteConfiguration() // add this line
}

Objective-C

Objective-C complete initialisation example

LDConfig* config = [[LDConfig alloc] initWithMobileKey: @"<YOUR-KEY>" autoEnvAttributes:AutoEnvAttributesEnabled];

// add this block of code 
APLFetchRemoteConfiguration(^NSObject* (NSString* propertyKey, APLRemotePropertyType propertyType, NSObject* defaultValue) {
    if (propertyType == APLRemotePropertyTypeBool) {
        return [NSNumber numberWithBool: [[LDClient get] boolVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) boolValue]]];
    } else if (propertyType == APLRemotePropertyTypeInt) {
        return [NSNumber numberWithInteger: [[LDClient get] integerVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) integerValue]]];
    } else if (propertyType == APLRemotePropertyTypeDouble) {
        return [NSNumber numberWithDouble: [[LDClient get] doubleVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) doubleValue]]];
    } else {
        return [[LDClient get] stringVariationForKey: propertyKey defaultValue: (NSString*) defaultValue];
    }
});

LDContext* context = [[[[LDContextBuilder alloc] initWithKey: @"<YOUR-CONTEXT>"] build] success];
[LDClient startWithConfiguration:config context:context startWaitSeconds:5.0 completion:^(bool timedOut) {
    if (!timedOut) {
        APLFlushRemoteConfiguration(); // add this line
    }
}];

[[LDClient get] observeAllKeysWithOwner: self handler: ^(NSDictionary<NSString *,LDChangedFlag *> *handler) {
    APLFlushRemoteConfiguration(); // add this line
}];

Best practice and usage

Swift

Replace all calls to Launch Darkly boolVariation(forKey:defaultValue:), intVariation(forKey:defaultValue:), doubleVariation(forKey:defaultValue), stringVariation(forKey:defaultValue:)

if (LDClient.get()!.boolVariation(forKey: "alwaysDarkMode", defaultValue: false)) {
    ...

with the following:

if (CONFIGURATION().alwaysDarkMode) {
    ...

Objective-C

Replace all calls to Launch Darkly boolVariationForKey:defaultValue:, intVariationForKey:defaultValue:, doubleVariationForKey:defaultValue, stringVariationForKey:defaultValue:

if ([[LDClient get] boolVariationForKey: @"alwaysDarkMode" defaultValue: NO]) {
    ...

with the following:

if (CONFIGURATION.alwaysDarkMode) {
    ...