Apple Push Notification Service - 推播服務

最近在研究怎麼收送push notification，以及怎麼架設notification server。


推播服務的介紹及運作方式可以參考：

• Local and Push Notification Programming Guide: Apple Push Notification Service

簡單來說就是每個iOS的app第一次開啓時會向apple註冊推播服務，然後得到專屬的device token，可以想像成擁有專屬的tunnel，再來只要向apple的server傳送message(JSON格式)，並帶上target device token，server就會自動幫你轉傳給對方。



寫一個小小的測試程式

• Programming Apple Push Notification Services | mobiForge

網站說明非常清楚，大致上的流程如下：

• 登入 iOS dev center 然後創建一個新的 App ID
• 開啓 push notification service
• 下載 "Development Push SSL Certificate" 及 "Provisioning Profile"

Receiver (iOS app):

• 安裝 provisioning profile
• 設定 identifier
• Write the code to register from remote notification server and get "device token"

範例：
要求使用者開啓 Push notification 服務

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [[UIApplication sharedApplication]registerForRemoteNotificationTypes:
  (UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound)];
}

Implement 3個 delegate

- (void)application:(UIApplication *)app didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken
{ 
    /* Get device token */ 
    NSString *strDevToken = [NSString stringWithFormat:@"%@", deviceToken];

    /* Replace '<', '>' and ' ' */
    NSCharacterSet *charDummy = [NSCharacterSet characterSetWithCharactersInString:@"<> "];
    strDevToken = [[strDevToken componentsSeparatedByCharactersInSet: charDummy] componentsJoinedByString: @""];
    NSLog(@"Device token=[%@]", strDevToken);

    /* 可以把token傳到server，之後server就可以靠它送推播給使用者了 */
}

- (void)application:(UIApplication *)app didFailToRegisterForRemoteNotificationsWithError:(NSError *)err
{
    NSLog(@"Error=[%@]", err);
    // TODO: when user do not allow push notification service, pop the warning message.
}

// This function called when receive notification and app is in the foreground.
- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo 
{
    /* 把收到的推播列舉出來 */
    for (id key in userInfo) {
        NSLog(@"Key=[%@], Value=[%@]", key, [userInfo objectForKey:key]); 
    }

    /* 印出 Badge number */
    NSLog(@"Badge: %@", [[userInfo objectForKey:@"aps"] objectForKey:@"badge"];

}

Sender (MacOS app):

• Base on sample code "PushMeBaby"
• Install "Development Push SSL Certificate"
• Set target device token then send

參考資料

• iPhone Software Development: APNS Client Development Certificate Available Now
• 怎样编写Apple Push Notification服务器

至於要如何架設APNS，可以參考下一篇：架設 Apple Push Notification Provider Server