我正在使用Amazon Web Services的简单通知服务(SNS)开发iOS应用程序.此时,应用程序将设备注册到主题,并可以接收推送通知,这些通知将发布到主题.可以将设备订阅到许多主题.
现在我正在尝试从特定主题取消订阅设备,但SNSUnsubscribeRequest需要SubscriptionARN.我试图从设备中使用EndpointARN,但似乎我要为EndpointARN和TopicARN的组合使用额外的SubscriptionARN.我如何获得此ARN？
在这篇文章中：How do you get the arn of a subscription?他们要求提供整个订阅者列表,并将每个EndpointARN与设备的EndpointARN进行比较.这不可能是我想的正确方法.
// Check if endpoint exist
if (endpointARN == nil) {
dispatch_async(dispatch_get_main_queue(),^{
[[self universalAlertsWithTitle:@"endpointARN not found!" andMessage:@"Please create an endpoint for this device before subscribe to topic"] show];
});
return NO;
}
// Create topic if not exist
NSString *topicARN = [self findTopicARNFor:topic];
if (!topicARN) {
[self createTopic:topic];
topicARN = [self findTopicARNFor:topic];
}
// Subscribe to topic if exist
if (topicARN) {
SNSSubscribeRequest *subscribeRequest = [[SNSSubscribeRequest alloc] initWithTopicArn:topicARN andProtocol:@"application" andEndpoint:endpointARN];
SNSSubscribeResponse *subscribeResponse = [snsClient subscribe:subscribeRequest];
if (subscribeResponse.error != nil) {
NSLog(@"Error: %@",subscribeResponse.error);
dispatch_async(dispatch_get_main_queue(),^{
[[self universalAlertsWithTitle:@"Subscription Error" andMessage:subscribeResponse.error.userInfo.description] show];
});
return NO;
}
}
return YES;
findTopicARNForTopic方法已遍历主题列表,并将后缀与主题名称进行比较.我真的不知道这是不是最好的做法.
NSString *topicARN = [self findTopicARNFor:topic];
if (topicARN) {
SNSUnsubscribeRequest *unsubscribeRequest = [[SNSUnsubscribeRequest alloc] initWithSubscriptionArn:topicARN];
SNSUnsubscribeResponse *unsubscribeResponse = [snsClient unsubscribe:unsubscribeRequest];
if (unsubscribeResponse.error) {
NSLog(@"Error: %@",unsubscribeResponse.error);
}
}
解决方法
现在我要求整个订户列表并将EndpointARN与设备的EndpointARN进行比较.使用以下方法我得到订阅arn：
- (NSString *)findSubscriptionARNForTopicARN:(NSString *)topicARN
{
// Iterate over each subscription arn list for a topic arn
NSString *nextToken = nil;
do {
SNSListSubscriptionsByTopicRequest *listSubscriptionRequest = [[SNSListSubscriptionsByTopicRequest alloc] initWithTopicArn:topicARN];
SNSListSubscriptionsByTopicResponse *response = [snsClient listSubscriptionsByTopic:listSubscriptionRequest];
if (response.error) {
NSLog(@"Error: %@",response.error);
return nil;
}
// Compare endpoint arn of subscription arn with endpoint arn of this device
for (SNSSubscription *subscription in response.subscriptions) {
if ([subscription.endpoint isEqualToString:endpointARN]) {
return subscription.subscriptionArn;
}
}
nextToken = response.nextToken;
} while (nextToken != nil);
return nil;
}
- (void)unsubscribeDeviceFromTopic:(NSString *)topic
{
NSString *subscriptionARN = [self findSubscriptionARNForTopic:topic];
if (subscriptionARN) {
SNSUnsubscribeRequest *unsubscribeRequest = [[SNSUnsubscribeRequest alloc] initWithSubscriptionArn:subscriptionARN];
SNSUnsubscribeResponse *unsubscribeResponse = [snsClient unsubscribe:unsubscribeRequest];
if (unsubscribeResponse.error) {
NSLog(@"Error: %@",unsubscribeResponse.error);
}
}
}
