Recreate an NSURLSession for updates to the fetch timeout. (#3683)

Author: dmandar

FirebaseRemoteConfig/Sources/FIRRemoteConfig.m

@@ -168,6 +168,8 @@ - (instancetype)initWithAppName:(NSString *)appName
     /// Serial queue for read and write lock.
     _queue = [FIRRemoteConfig sharedRemoteConfigSerialQueue];
 
+    // Initialize with default config settings.
+    [self setDefaultConfigSettings];
     _configFetch = [[RCNConfigFetch alloc] initWithContent:_configContent
                                                  DBManager:_DBManager
                                                   settings:_settings
@@ -178,12 +180,17 @@ - (instancetype)initWithAppName:(NSString *)appName
                                                    options:options];
 
     [_settings loadConfigFromMetadataTable];
-    self->_settings.fetchTimeout = RCNHTTPDefaultConnectionTimeout;
-    self->_settings.minimumFetchInterval = RCNDefaultMinimumFetchInterval;
   }
   return self;
 }
 
+// Initialize with default config settings.
+- (void)setDefaultConfigSettings {
+  // Set the default config settings.
+  self->_settings.fetchTimeout = RCNHTTPDefaultConnectionTimeout;
+  self->_settings.minimumFetchInterval = RCNDefaultMinimumFetchInterval;
+}
+
 - (void)ensureInitializedWithCompletionHandler:
     (nonnull FIRRemoteConfigInitializationCompletion)completionHandler {
   __weak FIRRemoteConfig *weakSelf = self;
@@ -592,6 +599,8 @@ - (FIRRemoteConfigSettings *)configSettings {
       [[FIRRemoteConfigSettings alloc] initWithDeveloperModeEnabled:developerModeEnabled];
   settings.minimumFetchInterval = minimumFetchInterval;
   settings.fetchTimeout = fetchTimeout;
+  /// The NSURLSession needs to be recreated whenever the fetch timeout may be updated.
+  [_configFetch recreateNetworkSession];
   return settings;
 }
 
@@ -607,6 +616,8 @@ - (void)setConfigSettings:(FIRRemoteConfigSettings *)configSettings {
     self->_settings.customVariables = settingsToSave;
     self->_settings.minimumFetchInterval = configSettings.minimumFetchInterval;
     self->_settings.fetchTimeout = configSettings.fetchTimeout;
+    /// The NSURLSession needs to be recreated whenever the fetch timeout may be updated.
+    [self->_configFetch recreateNetworkSession];
     FIRLogDebug(kFIRLoggerRemoteConfig, @"I-RCN000067",
                 @"Successfully set configSettings. Developer Mode: %@, Minimum Fetch Interval:%f, "
                 @"Fetch timeout:%f",

FirebaseRemoteConfig/Sources/RCNConfigFetch.h

@@ -53,6 +53,9 @@ typedef void (^RCNConfigFetcherTestBlock)(RCNConfigFetcherCompletion completion)
 - (void)fetchAllConfigsWithExpirationDuration:(NSTimeInterval)expirationDuration
                             completionHandler:(FIRRemoteConfigFetchCompletion)completionHandler;
 
+/// Add the ability to update NSURLSession's timeout after a session has already been created.
+- (void)recreateNetworkSession;
+
 /// Sets the test block to mock the fetch response instead of performing the fetch task from server.
 + (void)setGlobalTestBlock:(RCNConfigFetcherTestBlock)block;
 

FirebaseRemoteConfig/Sources/RCNFetch.m

@@ -110,6 +110,19 @@ - (instancetype)initWithContent:(RCNConfigContent *)content
   return self;
 }
 
+/// Force a new NSURLSession creation for updated config.
+- (void)recreateNetworkSession {
+  if (_fetchSession) {
+    [_fetchSession invalidateAndCancel];
+  }
+  _fetchSession = [self newFetchSession];
+}
+
+/// Return the current session. (Tests).
+- (NSURLSession *)currentNetworkSession {
+  return _fetchSession;
+}
+
 - (void)dealloc {
   [_fetchSession invalidateAndCancel];
 }

FirebaseRemoteConfig/Tests/Unit/RCNRemoteConfigTest.m

@@ -49,6 +49,7 @@ - (NSURLSessionDataTask *)URLSessionDataTaskWithContent:(NSData *)content
 - (void)fetchWithUserProperties:(NSDictionary *)userProperties
               completionHandler:(FIRRemoteConfigFetchCompletion)completionHandler;
 - (NSString *)constructServerURL;
+- (NSURLSession *)currentNetworkSession;
 @end
 
 @interface FIRRemoteConfig (ForTest)
@@ -1138,6 +1139,10 @@ - (void)testSetFetchTimeoutConfigSetting {
     settings.fetchTimeout = 1;
     [_configInstances[i] setConfigSettings:settings];
     XCTAssertEqual([_configInstances[i] configSettings].fetchTimeout, 1);
+    NSURLSession *networkSession = [_configFetch[i] currentNetworkSession];
+    XCTAssertNotNil(networkSession);
+    XCTAssertEqual(networkSession.configuration.timeoutIntervalForResource, 1);
+    XCTAssertEqual(networkSession.configuration.timeoutIntervalForRequest, 1);
   }
 }