GCM(Google Cloud Messaging)

GCM이란? 말그대로 구글에서 제공하는 알림 메시지 기능이다.

서버측에서 데이터를 조작하여 앱에 알림바 형태로 제공할 수 있는 기능이며,

이전에는 IOS에서는 APNS Android에서는 GCM을 이용하곤 했는데,

몇년전에 통합되어 GCM으로 두 서비스 제공이 가능해졌다.

//AppDelegate.h

#import <Google/CloudMessaging.h>
#import <UIKit/UIKit.h>
 
@interface AppDelegate : UIResponder <UIApplicationDelegate, GGLInstanceIDDelegate, GCMReceiverDelegate>
 
@property(nonatomic, strong) UIWindow *window;
@property(nonatomic, readonly, strong) NSString *registrationKey;
@property(nonatomic, readonly, strong) NSString *messageKey;
@property(nonatomic, readonly, strong) NSString *gcmSenderID;
@property(nonatomic, readonly, strong) NSDictionary *registrationOptions;
 
@end
 

//AppDelegate.m

//
//  Copyright (c) 2015 Google Inc.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//
 
#import "AppDelegate.h"
 
@interface AppDelegate ()
@property(nonatomic, strong) void (^registrationHandler)
    (NSString *registrationToken, NSError *error);
@property(nonatomic, assign) BOOL connectedToGCM;
@property(nonatomic, strong) NSString* registrationToken;
@property(nonatomic, assign) BOOL subscribedToTopic;
@end
 
NSString *const SubscriptionTopic = @"/topics/global";
 
@implementation AppDelegate
 
// [START register_for_remote_notifications]
- (BOOL)application:(UIApplication *)application
      didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  // [START_EXCLUDE]
  _registrationKey = @"onRegistrationCompleted";
  _messageKey = @"onMessageReceived";
  // Configure the Google context: parses the GoogleService-Info.plist, and initializes
  // the services that have entries in the file
  NSError* configureError;
  [[GGLContext sharedInstance] configureWithError:&configureError];
  NSAssert(!configureError, @"Error configuring Google services: %@", configureError);
  _gcmSenderID = [[[GGLContext sharedInstance] configuration] gcmSenderID];
  // Register for remote notifications
  if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_7_1) {
    // iOS 7.1 or earlier
    UIRemoteNotificationType allNotificationTypes =
        (UIRemoteNotificationTypeSound | UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeBadge);
    [application registerForRemoteNotificationTypes:allNotificationTypes];
  } else {
    // iOS 8 or later
    // [END_EXCLUDE]
    UIUserNotificationType allNotificationTypes =
        (UIUserNotificationTypeSound | UIUserNotificationTypeAlert | UIUserNotificationTypeBadge);
    UIUserNotificationSettings *settings =
        [UIUserNotificationSettings settingsForTypes:allNotificationTypes categories:nil];
    [[UIApplication sharedApplication] registerUserNotificationSettings:settings];
    [[UIApplication sharedApplication] registerForRemoteNotifications];
  }
  // [END register_for_remote_notifications]
  // [START start_gcm_service]
  GCMConfig *gcmConfig = [GCMConfig defaultConfig];
  gcmConfig.receiverDelegate = self;
  [[GCMService sharedInstance] startWithConfig:gcmConfig];
  // [END start_gcm_service]
  __weak typeof(self) weakSelf = self;
  // Handler for registration token request
  _registrationHandler = ^(NSString *registrationToken, NSError *error){
    if (registrationToken != nil) {
      weakSelf.registrationToken = registrationToken;
      NSLog(@"Registration Token: %@", registrationToken);
      [weakSelf subscribeToTopic];
      NSDictionary *userInfo = @{@"registrationToken":registrationToken};
      [[NSNotificationCenter defaultCenter] postNotificationName:weakSelf.registrationKey
                                                          object:nil
                                                        userInfo:userInfo];
    } else {
      NSLog(@"Registration to GCM failed with error: %@", error.localizedDescription);
      NSDictionary *userInfo = @{@"error":error.localizedDescription};
      [[NSNotificationCenter defaultCenter] postNotificationName:weakSelf.registrationKey
                                                          object:nil
                                                        userInfo:userInfo];
    }
  };
  return YES;
}
 
- (void)subscribeToTopic {
  // If the app has a registration token and is connected to GCM, proceed to subscribe to the
  // topic
  if (_registrationToken && _connectedToGCM) {
    [[GCMPubSub sharedInstance] subscribeWithToken:_registrationToken
                                             topic:SubscriptionTopic
                                           options:nil
                                           handler:^(NSError *error) {
                                             if (error) {
                                               // Treat the "already subscribed" error more gently
                                               if (error.code == 3001) {
                                                 NSLog(@"Already subscribed to %@",
                                                       SubscriptionTopic);
                                               } else {
                                                 NSLog(@"Subscription failed: %@",
                                                       error.localizedDescription);
                                               }
                                             } else {
                                               self.subscribedToTopic = true;
                                               NSLog(@"Subscribed to %@", SubscriptionTopic);
                                             }
                                           }];
  }
}
 
// [START connect_gcm_service]
- (void)applicationDidBecomeActive:(UIApplication *)application {
  // Connect to the GCM server to receive non-APNS notifications
  [[GCMService sharedInstance] connectWithHandler:^(NSError *error) {
    if (error) {
      NSLog(@"Could not connect to GCM: %@", error.localizedDescription);
    } else {
      _connectedToGCM = true;
      NSLog(@"Connected to GCM");
      // [START_EXCLUDE]
      [self subscribeToTopic];
      // [END_EXCLUDE]
    }
  }];
}
// [END connect_gcm_service]
 
// [START disconnect_gcm_service]
- (void)applicationDidEnterBackground:(UIApplication *)application {
  [[GCMService sharedInstance] disconnect];
  // [START_EXCLUDE]
  _connectedToGCM = NO;
  // [END_EXCLUDE]
}
// [END disconnect_gcm_service]
 
// [START receive_apns_token]
- (void)application:(UIApplication *)application
    didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken {
// [END receive_apns_token]
  // [START get_gcm_reg_token]
  // Create a config and set a delegate that implements the GGLInstaceIDDelegate protocol.
  GGLInstanceIDConfig *instanceIDConfig = [GGLInstanceIDConfig defaultConfig];
  instanceIDConfig.delegate = self;
  // Start the GGLInstanceID shared instance with the that config and request a registration
  // token to enable reception of notifications
  [[GGLInstanceID sharedInstance] startWithConfig:instanceIDConfig];
  _registrationOptions = @{kGGLInstanceIDRegisterAPNSOption:deviceToken,
                           kGGLInstanceIDAPNSServerTypeSandboxOption:@YES};
  [[GGLInstanceID sharedInstance] tokenWithAuthorizedEntity:_gcmSenderID
                                                      scope:kGGLInstanceIDScopeGCM
                                                    options:_registrationOptions
                                                    handler:_registrationHandler];
  // [END get_gcm_reg_token]
}
 
// [START receive_apns_token_error]
- (void)application:(UIApplication *)application
    didFailToRegisterForRemoteNotificationsWithError:(NSError *)error {
  NSLog(@"Registration for remote notification failed with error: %@", error.localizedDescription);
// [END receive_apns_token_error]
  NSDictionary *userInfo = @{@"error" :error.localizedDescription};
  [[NSNotificationCenter defaultCenter] postNotificationName:_registrationKey
                                                      object:nil
                                                    userInfo:userInfo];
}
 
// [START ack_message_reception]
- (void)application:(UIApplication *)application
    didReceiveRemoteNotification:(NSDictionary *)userInfo {
  NSLog(@"Notification received: %@", userInfo);
  // This works only if the app started the GCM service
  [[GCMService sharedInstance] appDidReceiveMessage:userInfo];
  // Handle the received message
  // [START_EXCLUDE]
  [[NSNotificationCenter defaultCenter] postNotificationName:_messageKey
                                                      object:nil
                                                    userInfo:userInfo];
  // [END_EXCLUDE]
}
 
- (void)application:(UIApplication *)application
    didReceiveRemoteNotification:(NSDictionary *)userInfo
    fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))handler {
  NSLog(@"Notification received: %@", userInfo);
  // This works only if the app started the GCM service
  [[GCMService sharedInstance] appDidReceiveMessage:userInfo];
  // Handle the received message
  // Invoke the completion handler passing the appropriate UIBackgroundFetchResult value
  // [START_EXCLUDE]
  [[NSNotificationCenter defaultCenter] postNotificationName:_messageKey
                                                      object:nil
                                                    userInfo:userInfo];
  handler(UIBackgroundFetchResultNoData);
  // [END_EXCLUDE]
}
// [END ack_message_reception]
 
// [START on_token_refresh]
- (void)onTokenRefresh {
  // A rotation of the registration tokens is happening, so the app needs to request a new token.
  NSLog(@"The GCM registration token needs to be changed.");
  [[GGLInstanceID sharedInstance] tokenWithAuthorizedEntity:_gcmSenderID
                                                      scope:kGGLInstanceIDScopeGCM
                                                    options:_registrationOptions
                                                    handler:_registrationHandler];
}
// [END on_token_refresh]
 
// [START upstream_callbacks]
- (void)willSendDataMessageWithID:(NSString *)messageID error:(NSError *)error {
  if (error) {
    // Failed to send the message.
  } else {
    // Will send message, you can save the messageID to track the message
  }
}
 
- (void)didSendDataMessageWithID:(NSString *)messageID {
  // Did successfully send message identified by messageID
}
// [END upstream_callbacks]
 
- (void)didDeleteMessagesOnServer {
  // Some messages sent to this device were deleted on the GCM server before reception, likely
  // because the TTL expired. The client should notify the app server of this, so that the app
  // server can resend those messages.
}
 
@end

//ViewController.m

//
//  Copyright (c) 2015 Google Inc.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//
 
#import "AppDelegate.h"
#import "ViewController.h"
 
@implementation ViewController
 
- (void)viewDidLoad {
  [super viewDidLoad];
  AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
 
  //NotificationCenter 등록
  [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(updateRegistrationStatus:)
                                               name:appDelegate.registrationKey
                                             object:nil];
  [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(showReceivedMessage:)
                                               name:appDelegate.messageKey
                                             object:nil];
  _registrationProgressing.hidesWhenStopped = YES;
  [_registrationProgressing startAnimating];
}
 
- (void) updateRegistrationStatus:(NSNotification *) notification {
  [_registrationProgressing stopAnimating];
  if ([notification.userInfo objectForKey:@"error"]) {
    _registeringLabel.text = @"Error registering!";
    [self showAlert:@"Error registering with GCM" withMessage:notification.userInfo[@"error"]];
  } else {
    _registeringLabel.text = @"Registered!";
    NSString *message = @"Check the xcode debug console for the registration token that you can"
        " use with the demo server to send notifications to your device";
    [self showAlert:@"Registration Successful" withMessage:message];
  };
}
 
- (void) showReceivedMessage:(NSNotification *) notification {
  NSString *message = notification.userInfo[@"aps"][@"alert"];
  [self showAlert:@"Message received" withMessage:message];
}
 
- (void)showAlert:(NSString *)title withMessage:(NSString *) message{
  if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_7_1) {
    // iOS 7.1 or earlier
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title
                                                    message:message
                                                   delegate:nil
                                          cancelButtonTitle:@"Dismiss"
                                          otherButtonTitles:nil];
    [alert show];
  } else {
    //iOS 8 or later
    UIAlertController *alert =
        [UIAlertController alertControllerWithTitle:title
                                            message:message
                                     preferredStyle:UIAlertControllerStyleAlert];
 
    UIAlertAction *dismissAction = [UIAlertAction actionWithTitle:@"Dismiss"
                                                            style:UIAlertActionStyleDestructive
                                                          handler:nil];
 
    [alert addAction:dismissAction];
    [self presentViewController:alert animated:YES completion:nil];
  }
}
 
- (UIStatusBarStyle)preferredStatusBarStyle {
  return UIStatusBarStyleLightContent;
}
 
- (void)dealloc {
  [[NSNotificationCenter defaultCenter] removeObserver:self];
}
 
@end

//podfile

 
pod 'Google/CloudMessaging'