Diff ABT Experiments for real-time RC

FirebaseRemoteConfig/Sources/RCNConfigContent.m

@@ -25,6 +25,8 @@
 
 #import "FirebaseCore/Extension/FirebaseCoreInternal.h"
 
+static NSString *const kAffectedParameterKeys = @"affectedParameterKeys";
+
 @implementation RCNConfigContent {
   /// Active config data that is currently used.
   NSMutableDictionary *_activeConfig;
@@ -398,13 +400,108 @@ - (BOOL)checkAndWaitForInitialDatabaseLoad {
   return true;
 }
 
+/// Load active and fetched experiment payloads and return them in a map.
+- (NSDictionary<NSString *, NSMutableArray<NSData *> *> *)loadExperimentsPayloads {
+  __block NSMutableArray *activeExperimentPayloads = [[NSMutableArray alloc] init];
+  __block NSMutableArray *experimentPayloads = [[NSMutableArray alloc] init];
+
+  /// Load experiments from DB.
+  RCNDBCompletion completionHandler = ^(BOOL success, NSDictionary<NSString *, id> *result) {
+    if (result[@RCNExperimentTableKeyPayload]) {
+      experimentPayloads = [result[@RCNExperimentTableKeyPayload] mutableCopy];
+    }
+    if (result[@RCNExperimentTableKeyActivePayload]) {
+      activeExperimentPayloads = [result[@RCNExperimentTableKeyActivePayload] mutableCopy];
+    }
+  };
+  [_DBManager loadExperimentWithCompletionHandler:completionHandler];
+
+  return @{
+    @RCNExperimentTableKeyPayload : experimentPayloads,
+    @RCNExperimentTableKeyActivePayload : activeExperimentPayloads
+  };
+}
+
+/// Creates a map where the key is the config key and the value if the experiment description.
+- (NSMutableDictionary *)createExperimentsMap:(NSMutableArray<NSData *> *)experiments {
+  NSMutableDictionary<NSString *, NSMutableDictionary *> *experimentsMap =
+      [[NSMutableDictionary alloc] init];
+
+  /// Iterate through all the experiments and check if they contain `affectedParameterKeys`.
+  for (NSData *experiment in experiments) {
+    NSError *error;
+    NSDictionary *experimentJSON =
+        [NSJSONSerialization JSONObjectWithData:experiment
+                                        options:NSJSONReadingMutableContainers
+                                          error:&error];
+    if (!error && experimentJSON) {
+      if ([experimentJSON objectForKey:kAffectedParameterKeys]) {
+        NSMutableArray *configKeys =
+            (NSMutableArray *)[experimentJSON objectForKey:kAffectedParameterKeys];
+        NSMutableDictionary *experimentCopy = [experimentJSON mutableCopy];
+        /// Remove `affectedParameterKeys` because the values come out of order and could affect the
+        /// diffing.
+        [experimentCopy removeObjectForKey:kAffectedParameterKeys];
+
+        /// Map experiments to config keys.
+        for (NSString *key in configKeys) {
+          [experimentsMap setObject:experimentCopy forKey:key];
+        }
+      }
+    }
+  }
+
+  return experimentsMap;
+}
+
+/// Returns keys that were affected by experiment changes.
+- (NSMutableSet<NSString *> *)
+    getKeysAffectedByChangedExperiments:(NSMutableArray *)activeExperimentPayloads
+              fetchedExperimentPayloads:(NSMutableArray *)experimentPayloads {
+  NSMutableSet<NSString *> *changedKeys = [[NSMutableSet alloc] init];
+
+  /// Create config keys to experiments map.
+  NSMutableDictionary *activeExperimentsMap = [self createExperimentsMap:activeExperimentPayloads];
+  NSMutableDictionary *fetchedExperimentsMap = [self createExperimentsMap:experimentPayloads];
+
+  /// Iterate through active experiment's keys and compare them to fetched experiment's keys.
+  for (NSString *key in [activeExperimentsMap allKeys]) {
+    if (![fetchedExperimentsMap objectForKey:key]) {
+      [changedKeys addObject:key];
+    } else {
+      if (![[activeExperimentsMap objectForKey:key]
+              isEqualToDictionary:[fetchedExperimentsMap objectForKey:key]]) {
+        [changedKeys addObject:key];
+      }
+    }
+  }
+
+  /// Iterate through fetched experiment's keys and compare them to active experiment's keys.
+  for (NSString *key in [fetchedExperimentsMap allKeys]) {
+    if (![activeExperimentsMap objectForKey:key]) {
+      [changedKeys addObject:key];
+    } else {
+      if (![[fetchedExperimentsMap objectForKey:key]
+              isEqualToDictionary:[activeExperimentsMap objectForKey:key]]) {
+        [changedKeys addObject:key];
+      }
+    }
+  }
+
+  return changedKeys;
+}
+
 // Compare fetched config with active config and output what has changed
 - (FIRRemoteConfigUpdate *)getConfigUpdateForNamespace:(NSString *)FIRNamespace {
-  // TODO: handle diff in experiment metadata
-
   FIRRemoteConfigUpdate *configUpdate;
   NSMutableSet<NSString *> *updatedKeys = [[NSMutableSet alloc] init];
 
+  NSDictionary *experiments = [self loadExperimentsPayloads];
+  NSMutableSet *changedExperimentKeys = [self
+      getKeysAffectedByChangedExperiments:[experiments
+                                              objectForKey:@RCNExperimentTableKeyActivePayload]
+                fetchedExperimentPayloads:[experiments objectForKey:@RCNExperimentTableKeyPayload]];
+
   NSDictionary *fetchedConfig =
       _fetchedConfig[FIRNamespace] ? _fetchedConfig[FIRNamespace] : [[NSDictionary alloc] init];
   NSDictionary *activeConfig =
@@ -439,6 +536,11 @@ - (FIRRemoteConfigUpdate *)getConfigUpdateForNamespace:(NSString *)FIRNamespace
     }
   }
 
+  // Add params affected by changed experiments.
+  for (NSString *key in changedExperimentKeys) {
+    [updatedKeys addObject:key];
+  }
+
   configUpdate = [[FIRRemoteConfigUpdate alloc] initWithUpdatedKeys:updatedKeys];
   return configUpdate;
 }

FirebaseRemoteConfig/Tests/Unit/RCNConfigContentTest.m

@@ -26,6 +26,9 @@
 #import "FirebaseRemoteConfig/Tests/Unit/RCNTestUtilities.h"
 
 @interface RCNConfigContent (Testing)
+- (NSMutableSet<NSString *> *)
+    getKeysAffectedByChangedExperiments:(NSMutableArray *)activeExperimentPayloads
+              fetchedExperimentPayloads:(NSMutableArray *)experimentPayloads;
 - (BOOL)checkAndWaitForInitialDatabaseLoad;
 @end
 
@@ -349,6 +352,129 @@ - (void)testConfigUpdate_noChange_emptyResponse {
   XCTAssertTrue([update updatedKeys].count == 0);
 }
 
+- (void)testConfigUpdate_noParamChange_butExperimentChange {
+  NSString *namespace = @"test_namespace";
+  RCNConfigContent *configContent = [[RCNConfigContent alloc] initWithDBManager:nil];
+  NSMutableSet<NSString *> *experimentKeys = [[NSMutableSet alloc] init];
+  [experimentKeys addObject:@"key_2"];
+  id configMock = OCMPartialMock(configContent);
+  OCMStub([configMock getKeysAffectedByChangedExperiments:OCMOCK_ANY
+                                fetchedExperimentPayloads:OCMOCK_ANY])
+      .andReturn(experimentKeys);
+
+  // populate fetched config
+  NSMutableDictionary *fetchResponse =
+      [self createFetchResponseWithConfigEntries:@{@"key1" : @"value1"} p13nMetadata:nil];
+  [configMock updateConfigContentWithResponse:fetchResponse forNamespace:namespace];
+
+  // active config is the same as fetched config
+  FIRRemoteConfigValue *value =
+      [[FIRRemoteConfigValue alloc] initWithData:[@"value1" dataUsingEncoding:NSUTF8StringEncoding]
+                                          source:FIRRemoteConfigSourceRemote];
+  NSDictionary *namespaceToConfig = @{namespace : @{@"key1" : value}};
+  [configMock copyFromDictionary:namespaceToConfig
+                        toSource:RCNDBSourceActive
+                    forNamespace:namespace];
+
+  FIRRemoteConfigUpdate *update = [configMock getConfigUpdateForNamespace:namespace];
+
+  XCTAssertTrue([update updatedKeys].count == 1);
+  XCTAssertTrue([[update updatedKeys] containsObject:@"key_2"]);
+}
+
+- (void)testExperimentDiff_addedExperiment {
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  NSMutableArray *activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  NSError *dataError;
+  NSMutableDictionary *payload =
+      [NSJSONSerialization JSONObjectWithData:payloadData1
+                                      options:NSJSONReadingMutableContainers
+                                        error:&dataError];
+  [payload setValue:@"exp_2" forKey:@"experimentId"];
+  NSError *jsonError;
+  NSData *payloadData2 = [NSJSONSerialization dataWithJSONObject:payload
+                                                         options:kNilOptions
+                                                           error:&jsonError];
+  NSMutableArray *experimentPayloads = [@[ payloadData1, payloadData2 ] mutableCopy];
+
+  RCNConfigContent *configContent = [[RCNConfigContent alloc] initWithDBManager:nil];
+  NSMutableSet<NSString *> *changedKeys =
+      [configContent getKeysAffectedByChangedExperiments:activeExperimentPayloads
+                               fetchedExperimentPayloads:experimentPayloads];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_1"]);
+}
+
+- (void)testExperimentDiff_changedExperimentMetadata {
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  NSMutableArray *activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  NSError *dataError;
+  NSMutableDictionary *payload =
+      [NSJSONSerialization JSONObjectWithData:payloadData1
+                                      options:NSJSONReadingMutableContainers
+                                        error:&dataError];
+  [payload setValue:@"var_2" forKey:@"variantId"];
+  NSError *jsonError;
+  NSData *payloadData2 = [NSJSONSerialization dataWithJSONObject:payload
+                                                         options:kNilOptions
+                                                           error:&jsonError];
+  NSMutableArray *experimentPayloads = [@[ payloadData1, payloadData2 ] mutableCopy];
+
+  RCNConfigContent *configContent = [[RCNConfigContent alloc] initWithDBManager:nil];
+  NSMutableSet<NSString *> *changedKeys =
+      [configContent getKeysAffectedByChangedExperiments:activeExperimentPayloads
+                               fetchedExperimentPayloads:experimentPayloads];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_1"]);
+}
+
+- (void)testExperimentDiff_changedExperimentKeys {
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  NSMutableArray *activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  NSError *dataError;
+  NSMutableDictionary *payload =
+      [NSJSONSerialization JSONObjectWithData:payloadData1
+                                      options:NSJSONReadingMutableContainers
+                                        error:&dataError];
+  [payload setValue:@[ @"test_key_1", @"test_key_2" ] forKey:@"affectedParameterKeys"];
+  NSError *jsonError;
+  NSData *payloadData2 = [NSJSONSerialization dataWithJSONObject:payload
+                                                         options:kNilOptions
+                                                           error:&jsonError];
+  NSMutableArray *experimentPayloads = [@[ payloadData1, payloadData2 ] mutableCopy];
+
+  RCNConfigContent *configContent = [[RCNConfigContent alloc] initWithDBManager:nil];
+  NSMutableSet<NSString *> *changedKeys =
+      [configContent getKeysAffectedByChangedExperiments:activeExperimentPayloads
+                               fetchedExperimentPayloads:experimentPayloads];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_2"]);
+}
+
+- (void)testExperimentDiff_deletedExperiment {
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  NSMutableArray *activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+  NSMutableArray *experimentPayloads = [@[] mutableCopy];
+
+  RCNConfigContent *configContent = [[RCNConfigContent alloc] initWithDBManager:nil];
+  NSMutableSet<NSString *> *changedKeys =
+      [configContent getKeysAffectedByChangedExperiments:activeExperimentPayloads
+                               fetchedExperimentPayloads:experimentPayloads];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_1"]);
+}
+
+- (void)testExperimentDiff_noChange {
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  NSMutableArray *activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+  NSMutableArray *experimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  RCNConfigContent *configContent = [[RCNConfigContent alloc] initWithDBManager:nil];
+  NSMutableSet<NSString *> *changedKeys =
+      [configContent getKeysAffectedByChangedExperiments:activeExperimentPayloads
+                               fetchedExperimentPayloads:experimentPayloads];
+  XCTAssertTrue([changedKeys count] == 0);
+}
+
 - (void)testConfigUpdate_paramAdded_returnsNewKey {
   NSString *namespace = @"test_namespace";
   NSString *newParam = @"key2";
@@ -501,4 +627,29 @@ - (NSMutableDictionary *)createFetchResponseWithConfigEntries:(NSDictionary *)co
   return fetchResponse;
 }
 
++ (NSData *)payloadDataFromTestFile {
+#if SWIFT_PACKAGE
+  NSBundle *bundle = SWIFTPM_MODULE_BUNDLE;
+#else
+  NSBundle *bundle = [NSBundle bundleForClass:[self class]];
+#endif
+  NSString *testJsonDataFilePath = [bundle pathForResource:@"TestABTPayload" ofType:@"txt"];
+  NSError *readTextError = nil;
+  NSString *fileText = [[NSString alloc] initWithContentsOfFile:testJsonDataFilePath
+                                                       encoding:NSUTF8StringEncoding
+                                                          error:&readTextError];
+
+  NSData *fileData = [fileText dataUsingEncoding:kCFStringEncodingUTF8];
+
+  NSError *jsonDictionaryError = nil;
+  NSMutableDictionary *jsonDictionary =
+      [[NSJSONSerialization JSONObjectWithData:fileData
+                                       options:kNilOptions
+                                         error:&jsonDictionaryError] mutableCopy];
+  NSError *jsonDataError = nil;
+  return [NSJSONSerialization dataWithJSONObject:jsonDictionary
+                                         options:kNilOptions
+                                           error:&jsonDataError];
+}
+
 @end

FirebaseRemoteConfig/Tests/Unit/TestABTPayload.txt

@@ -15,5 +15,6 @@
     {
       "experimentId": "exp_1"
     }
-  ]
+  ],
+  "affectedParameterKeys": ["test_key_1"]
 }