isFeatureEnabled API (#207)

* Feature flag & rollout parsing

* New Models added

* variation variable usage mapping

* Feature variable and its usage parsing

* demoTestDatafile version upgraded to 4 and maintain compatibility to v3

* Test cases added for new models

* get back to Asynchronous Initialization of OPTLYManager

* CR updated

* Feature flag & rollout bucketing decision

* Decision Service Logic added

* Test cases for getVariationForFeatureExperiment

* Test cases for getVariationForFeatureRollout

* CR updated

* fix - file references

* replaced experimentId & variationId with their objects in FeatureDecision

* isFeatureEnabled API

* implemented API with test cases

* added a test case for mutex group experiments

* Fixed crash with nil check of completion block

* Removed xcode analyze warnings

*  Merge branch 'master' into arafay/isFeatureEnabled-API

* Merge branch 'master' into arafay/isFeatureEnabled-API

* master:
  Feature flag & rollout bucket decision (#206)
  Feature flag & rollout parsing (#205)

# Conflicts:
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYDecisionService.m
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureDecision.h
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureDecision.m
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureFlag.h
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureFlag.m
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureVariable.h
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureVariable.m
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYLoggerMessages.h
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYLoggerMessages.m
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYProjectConfig.m
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYRollout.h
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYRollout.m
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYVariableUsage.h
#	OptimizelySDKCore/OptimizelySDKCore/OPTLYVariableUsage.m
#	OptimizelySDKCore/OptimizelySDKCoreTests/OPTLYDecisionServiceTest.m
#	OptimizelySDKCore/OptimizelySDKCoreTests/OPTLYProjectConfigTest.m
#	OptimizelySDKCore/OptimizelySDKCoreTests/OptimizelyTest.m
#	OptimizelySDKCore/OptimizelySDKCoreTests/TestData/optimizely_6372300739_v4.json
#	OptimizelySDKCore/OptimizelySDKCoreTests/TestData/test_data_10_experiments.json
#	OptimizelySDKUniversal/OptimizelySDKUniversal.xcodeproj/project.pbxproj

* fixes - after merge

Author: arafay-folio3

OptimizelySDKCore/OptimizelySDKCore/OPTLYBuilder.h

@@ -16,7 +16,7 @@
 
 #import <Foundation/Foundation.h>
 
-@class OPTLYBucketer, OPTLYEventBuilder, OPTLYEventBuilderDefault, OPTLYProjectConfig;
+@class OPTLYBucketer, OPTLYEventBuilder, OPTLYEventBuilderDefault, OPTLYProjectConfig, OPTLYDecisionService;
 @protocol OPTLYDatafileManager, OPTLYErrorHandler, OPTLYEventBuilder, OPTLYEventDispatcher, OPTLYLogger, OPTLYUserProfileService;
 
 /**
@@ -36,6 +36,8 @@ typedef void (^OPTLYBuilderBlock)(OPTLYBuilder * _Nullable builder);
 @property (nonatomic, readonly, strong, nullable) OPTLYProjectConfig *config;
 /// The bucketer created by the builder.
 @property (nonatomic, readonly, strong, nullable) OPTLYBucketer *bucketer;
+/// The decision service created by the builder.
+@property (nonatomic, readonly, strong, nullable) OPTLYDecisionService *decisionService;
 /// The event builder created by the builder.
 @property (nonatomic, readonly, strong, nullable) OPTLYEventBuilderDefault *eventBuilder;
 /// The error handler is by default set to one that is created by Optimizely. This default error handler can be overridden by any object that conforms to the OPTLYErrorHandler protocol.

OptimizelySDKCore/OptimizelySDKCore/OPTLYBuilder.m

@@ -21,6 +21,7 @@
 #import "OPTLYEventDispatcherBasic.h"
 #import "OPTLYLogger.h"
 #import "OPTLYProjectConfig.h"
+#import "OPTLYDecisionService.h"
 
 @implementation OPTLYBuilder
 
@@ -71,6 +72,7 @@ - (id)initWithBlock:(OPTLYBuilderBlock)block {
     }
 
     _bucketer = [[OPTLYBucketer alloc] initWithConfig:_config];
+    _decisionService = [[OPTLYDecisionService alloc] initWithProjectConfig:_config bucketer:_bucketer];
     _eventBuilder = [[OPTLYEventBuilderDefault alloc] init];
 
     return self;

OptimizelySDKCore/OptimizelySDKCore/OPTLYDatafileKeys.h

@@ -80,6 +80,7 @@ extern NSString * const OPTLYDatafileKeysFeatureFlagKey;
 extern NSString * const OPTLYDatafileKeysFeatureFlagRolloutId;
 extern NSString * const OPTLYDatafileKeysFeatureFlagExperimentIds;
 extern NSString * const OPTLYDatafileKeysFeatureFlagVariables;
+extern NSString * const OPTLYDatafileKeysFeatureFlagGroupId;
 // Feature Variable
 extern NSString * const OPTLYDatafileKeysFeatureVariableId;
 extern NSString * const OPTLYDatafileKeysFeatureVariableKey;

OptimizelySDKCore/OptimizelySDKCore/OPTLYDatafileKeys.m

@@ -76,6 +76,7 @@
 NSString * const OPTLYDatafileKeysFeatureFlagRolloutId      = @"rolloutId";
 NSString * const OPTLYDatafileKeysFeatureFlagExperimentIds  = @"experimentIds";
 NSString * const OPTLYDatafileKeysFeatureFlagVariables      = @"variables";
+NSString * const OPTLYDatafileKeysFeatureFlagGroupId        = @"groupId";
 // Feature Variable
 NSString * const OPTLYDatafileKeysFeatureVariableId             = @"id";
 NSString * const OPTLYDatafileKeysFeatureVariableKey            = @"key";

OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureFlag.h

@@ -21,6 +21,7 @@
 #import <OptimizelySDKCore/OPTLYJSONModelLib.h>
 #endif
 
+@class OPTLYProjectConfig;
 @protocol OPTLYFeatureVariable;
 @protocol OPTLYFeatureFlag
 @end
@@ -40,4 +41,11 @@
 /// an NSString to hold the group Id the feature belongs to.
 @property (nonatomic, strong, nullable) NSString<Optional> *groupId;
 
+/**
+ * Determines whether all the experiments in the feature flag belongs to the same mutex group
+ * @param config The project config object.
+ * @return YES if feature belongs to the same mutex group.
+ */
+- (BOOL)isValid:(nonnull OPTLYProjectConfig *)config;
+
 @end

OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureFlag.m

@@ -16,6 +16,8 @@
 
 #import "OPTLYFeatureFlag.h"
 #import "OPTLYDatafileKeys.h"
+#import "OPTLYProjectConfig.h"
+#import "OPTLYExperiment.h"
 
 @implementation OPTLYFeatureFlag
 
@@ -25,8 +27,33 @@ + (OPTLYJSONKeyMapper*)keyMapper
                                                              OPTLYDatafileKeysFeatureFlagKey            : @"key",
                                                              OPTLYDatafileKeysFeatureFlagRolloutId      : @"rolloutId",
                                                              OPTLYDatafileKeysFeatureFlagExperimentIds  : @"experimentIds",
-                                                             OPTLYDatafileKeysFeatureFlagVariables      : @"variables"
+                                                             OPTLYDatafileKeysFeatureFlagVariables      : @"variables",
+                                                             OPTLYDatafileKeysFeatureFlagGroupId        : @"groupId"
                                                              }];
 }
 
+- (BOOL)isValid:(OPTLYProjectConfig *)config {
+    if ([OPTLYFeatureFlag isEmptyArray:self.experimentIds]) {
+        return true;
+    }
+    if (self.experimentIds.count == 1) {
+        return true;
+    }
+    
+    NSString *groupId = [config getExperimentForId:[self.experimentIds firstObject]].groupId;
+    
+    for (int i = 1; i < self.experimentIds.count; i++)
+    {
+        // Every experiment should have the same group Id.
+        if ([config getExperimentForId:self.experimentIds[i]].groupId != groupId)
+            return false;
+    }
+    return true;
+}
+
++ (BOOL)isEmptyArray:(NSObject*)array {
+    return (!array
+            || ![array isKindOfClass:[NSArray class]]
+            || (((NSArray *)array).count == 0));
+}
 @end

OptimizelySDKCore/OptimizelySDKCore/OPTLYLoggerMessages.h

@@ -26,6 +26,12 @@ extern NSString *const OPTLYLoggerMessagesVariationUserAssigned;
 // info
 extern NSString *const OPTLYLoggerMessagesActivationSuccess;
 extern NSString *const OPTLYLoggerMessagesConversionSuccess;
+// error
+extern NSString *const OPTLYLoggerMessagesFeatureDisabledUserIdInvalid;
+extern NSString *const OPTLYLoggerMessagesFeatureDisabledFlagKeyInvalid;
+extern NSString *const OPTLYLoggerMessagesFeatureDisabled;
+extern NSString *const OPTLYLoggerMessagesFeatureEnabledNotExperimented;
+extern NSString *const OPTLYLoggerMessagesFeatureEnabled;
 
 // ---- Bucketer ----
 // debug

OptimizelySDKCore/OptimizelySDKCore/OPTLYLoggerMessages.m

@@ -22,6 +22,12 @@
 // info
 NSString *const OPTLYLoggerMessagesActivationSuccess = @"[OPTIMIZELY] Activating user %@ in experiment %@.";
 NSString *const OPTLYLoggerMessagesConversionSuccess = @"[OPTIMIZELY] Tracking event %@ for user %@.";
+// error
+NSString *const OPTLYLoggerMessagesFeatureDisabledUserIdInvalid = @"[OPTIMIZELY] User ID must not be empty for feature enabled.";
+NSString *const OPTLYLoggerMessagesFeatureDisabledFlagKeyInvalid = @"[OPTIMIZELY] Feature flag key must not be empty for feature enabled.";
+NSString *const OPTLYLoggerMessagesFeatureDisabled = @"[OPTIMIZELY] Feature flag %@ is not enabled for user %@.";
+NSString *const OPTLYLoggerMessagesFeatureEnabledNotExperimented = @"[OPTIMIZELY] The user %@ is not being experimented on feature %@.";
+NSString *const OPTLYLoggerMessagesFeatureEnabled = @"[OPTIMIZELY] Feature flag %@ is enabled for user %@.";
 
 // ---- Bucketer ----
 // debug

OptimizelySDKCore/OptimizelySDKCore/Optimizely.h

@@ -27,7 +27,7 @@ extern NSString * _Nonnull const OptimizelyNotificationsUserDictionaryEventNameK
 extern NSString * _Nonnull const OptimizelyNotificationsUserDictionaryEventValueKey;
 extern NSString * _Nonnull const OptimizelyNotificationsUserDictionaryExperimentVariationMappingKey;
 
-@class OPTLYProjectConfig, OPTLYVariation;
+@class OPTLYProjectConfig, OPTLYVariation, OPTLYDecisionService;
 @protocol OPTLYBucketer, OPTLYErrorHandler, OPTLYEventBuilder, OPTLYEventDispatcher, OPTLYLogger;
 
 @protocol Optimizely <NSObject>
@@ -121,6 +121,18 @@ extern NSString * _Nonnull const OptimizelyNotificationsUserDictionaryExperiment
                     userId:(nonnull NSString *)userId
               variationKey:(nullable NSString *)variationKey;
 
+#pragma mark - Feature Flag Methods
+
+/**
+ * Determine whether a feature is enabled.
+ * Send an impression event if the user is bucketed into an experiment using the feature.
+ * @param featureKey The key for the feature flag.
+ * @param userId The user ID to be used for bucketing.
+ * @param attributes The user's attributes.
+ * @return YES if feature is enabled, false otherwise.
+ */
+- (BOOL)isFeatureEnabled:(nullable NSString *)featureKey userId:(nullable NSString *)userId attributes:(nullable NSDictionary<NSString *, NSString *> *)attributes;
+
 #pragma mark - trackEvent methods
 /**
  * Track an event
@@ -193,6 +205,7 @@ extern NSString * _Nonnull const OptimizelyNotificationsUserDictionaryExperiment
 @interface Optimizely : NSObject <Optimizely>
 
 @property (nonatomic, strong, readonly, nullable) id<OPTLYBucketer> bucketer;
+@property (nonatomic, strong, readonly, nullable) OPTLYDecisionService *decisionService;
 @property (nonatomic, strong, readonly, nullable) OPTLYProjectConfig *config;
 @property (nonatomic, strong, readonly, nullable) id<OPTLYErrorHandler> errorHandler;
 @property (nonatomic, strong, readonly, nullable) id<OPTLYEventBuilder> eventBuilder;

OptimizelySDKCore/OptimizelySDKCore/Optimizely.m

@@ -31,6 +31,9 @@
 #import "OPTLYProjectConfig.h"
 #import "OPTLYUserProfileServiceBasic.h"
 #import "OPTLYVariation.h"
+#import "OPTLYFeatureFlag.h"
+#import "OPTLYFeatureDecision.h"
+#import "OPTLYDecisionService.h"
 
 NSString *const OptimizelyDidActivateExperimentNotification = @"OptimizelyExperimentActivated";
 NSString *const OptimizelyDidTrackEventNotification = @"OptimizelyEventTracked";
@@ -57,6 +60,7 @@ - (instancetype)initWithBuilder:(OPTLYBuilder *)builder {
     if (self != nil) {
         if (builder != nil) {
             _bucketer = builder.bucketer;
+            _decisionService = builder.decisionService;
             _config = builder.config;
             _eventBuilder = builder.eventBuilder;
             _eventDispatcher = builder.eventDispatcher;
@@ -104,10 +108,11 @@ - (OPTLYVariation *)activate:(NSString *)experimentKey
                     callback:(void (^)(NSError *))callback {
 
     // get variation
-    OPTLYVariation *variation = [self variation:experimentKey
-                                         userId:userId
-                                     attributes:attributes];
+    OPTLYVariation *variation = [self variation:experimentKey userId:userId attributes:attributes];
 
+    // get experiment
+    OPTLYExperiment *experiment = [self.config getExperimentForKey:experimentKey];
+
     if (!variation) {
         NSError *error = [self handleErrorLogsForActivateUser:userId experiment:experimentKey];
         if (callback) {
@@ -117,38 +122,24 @@ - (OPTLYVariation *)activate:(NSString *)experimentKey
     }
 
     // send impression event
-    NSDictionary *impressionEventParams = [self.eventBuilder buildImpressionEventTicket:self.config
-                                                                                 userId:userId
-                                                                          experimentKey:experimentKey
-                                                                            variationId:variation.variationId
-                                                                             attributes:attributes];
+    __weak typeof(self) weakSelf = self;
+    OPTLYVariation *sentVariation = [self sendImpressionEventFor:experiment variation:variation userId:userId attributes:attributes callback:^(NSError *error) {
+        if (error) {
+            [weakSelf handleErrorLogsForActivateUser:userId experiment:experimentKey];
+        }
+        if (callback) {
+            callback(error);
+        }
+    }];
 
-    if ([impressionEventParams count] == 0) {
+    if (!sentVariation) {
         NSError *error = [self handleErrorLogsForActivateUser:userId experiment:experimentKey];
         if (callback) {
             callback(error);
         }
         return nil;
     }
 
-    NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesEventDispatcherAttemptingToSendImpressionEvent, userId, experimentKey];
-    [self.logger logMessage:logMessage withLevel:OptimizelyLogLevelInfo];
-    
-    __weak typeof(self) weakSelf = self;
-    [self.eventDispatcher dispatchImpressionEvent:impressionEventParams
-                                         callback:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
-                                             if (error) {
-                                                 [weakSelf handleErrorLogsForActivateUser:userId experiment:experimentKey];
-                                             } else {
-                                                 NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesEventDispatcherActivationSuccess, userId, experimentKey];
-                                                 [weakSelf.logger logMessage:logMessage
-                                                                   withLevel:OptimizelyLogLevelInfo];
-                                             }
-                                             if (callback) {
-                                                 callback(error);
-                                             }
-                                         }];
-    
     NSMutableDictionary *userInfo = [NSMutableDictionary dictionaryWithDictionary:@{
                                                                                     OptimizelyNotificationsUserDictionaryVariationKey: variation
                                                                                     }];
@@ -203,6 +194,48 @@ - (BOOL)setForcedVariation:(nonnull NSString *)experimentKey
                               variationKey:variationKey];
 }
 
+#pragma mark - Feature Flag Methods
+
+- (BOOL)isFeatureEnabled:(NSString *)featureKey userId:(NSString *)userId attributes:(nullable NSDictionary<NSString *, NSString *> *)attributes {
+    if ([Optimizely isEmptyString:userId]) {
+        [self.logger logMessage:OPTLYLoggerMessagesFeatureDisabledUserIdInvalid withLevel:OptimizelyLogLevelError];
+        return false;
+    }
+    if ([Optimizely isEmptyString:featureKey]) {
+        [self.logger logMessage:OPTLYLoggerMessagesFeatureDisabledFlagKeyInvalid withLevel:OptimizelyLogLevelError];
+        return false;
+    }
+    
+    OPTLYFeatureFlag *featureFlag = [self.config getFeatureFlagForKey:featureKey];
+    if ([Optimizely isEmptyString:featureFlag.key]) {
+        [self.logger logMessage:OPTLYLoggerMessagesFeatureDisabledFlagKeyInvalid withLevel:OptimizelyLogLevelError];
+        return false;
+    }
+    if (![featureFlag isValid:self.config]) {
+        return false;
+    }
+    
+    OPTLYFeatureDecision *decision = [self.decisionService getVariationForFeature:featureFlag userId:userId attributes:attributes];
+    
+    if (!decision) {
+        NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesFeatureDisabled, featureKey, userId];
+        [self.logger logMessage:logMessage withLevel:OptimizelyLogLevelInfo];
+        return false;
+    }
+    
+    if ([decision.source isEqualToString:DecisionSourceExperiment]) {
+        [self sendImpressionEventFor:decision.experiment variation:decision.variation userId:userId attributes:attributes callback:nil];
+    } else {
+        NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesFeatureEnabledNotExperimented, userId, featureKey];
+        [self.logger logMessage:logMessage withLevel:OptimizelyLogLevelInfo];
+    }
+    
+    NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesFeatureEnabled, featureKey, userId];
+    [self.logger logMessage:logMessage withLevel:OptimizelyLogLevelInfo];
+    
+    return true;
+}
+
 #pragma mark trackEvent methods
 - (void)track:(NSString *)eventKey userId:(NSString *)userId
 {
@@ -357,4 +390,51 @@ - (NSError *)handleErrorLogsForActivateUser:(NSString *)userId
 - (NSString *)description {
     return [NSString stringWithFormat:@"config:%@\nlogger:%@\nerrorHandler:%@\neventDispatcher:%@\nuserProfile:%@", self.config, self.logger, self.errorHandler, self.eventDispatcher, self.userProfileService];
 }
+
+- (OPTLYVariation *)sendImpressionEventFor:(OPTLYExperiment *)experiment
+                                 variation:(OPTLYVariation *)variation
+                                    userId:(NSString *)userId
+                                attributes:(NSDictionary<NSString *,NSString *> *)attributes
+                                  callback:(void (^)(NSError *))callback {
+    
+    // send impression event
+    NSDictionary *impressionEventParams = [self.eventBuilder buildImpressionEventTicket:self.config
+                                                                                 userId:userId
+                                                                          experimentKey:experiment.experimentKey
+                                                                            variationId:variation.variationId
+                                                                             attributes:attributes];
+    
+    if ([Optimizely isEmptyDictionary:impressionEventParams]) {
+        return nil;
+    }
+    
+    NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesEventDispatcherAttemptingToSendImpressionEvent, userId, experiment.experimentKey];
+    [self.logger logMessage:logMessage withLevel:OptimizelyLogLevelInfo];
+    
+    __weak typeof(self) weakSelf = self;
+    [self.eventDispatcher dispatchImpressionEvent:impressionEventParams
+                                         callback:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
+                                             if (!error) {
+                                                 NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesEventDispatcherActivationSuccess, userId, experiment.experimentKey];
+                                                 [weakSelf.logger logMessage:logMessage
+                                                                   withLevel:OptimizelyLogLevelInfo];
+                                             }
+                                             if (callback) {
+                                                 callback(error);
+                                             }
+                                         }];
+    return variation;
+}
+
++ (BOOL)isEmptyString:(NSObject*)string {
+    return (!string
+            || ![string isKindOfClass:[NSString class]]
+            || [(NSString *)string isEqualToString:@""]);
+}
+
++ (BOOL)isEmptyDictionary:(NSObject*)dict {
+    return (!dict
+            || ![dict isKindOfClass:[NSDictionary class]]
+            || (((NSDictionary *)dict).count == 0));
+}
 @end