如何从amazon SNS主题取消订阅iOS设备？

我正在从AmazonWeb服务开发一个带有简单通知服务（SNS）的iOS应用程序。此时，应用程序将设备注册到某个主题，并可以接收推送通知，这些通知将发布到该主题。可以为设备订阅多个主题

现在我正试图从特定主题中取消订阅设备，但SNSUnsubscriberRequest需要一个SubscriptionARN。我尝试从设备中使用EndpointARN，但似乎我必须使用额外的SubscriptionARN来组合EndpointARN和TopicARN。我怎么得到这个阿恩

在本文中：他们要求提供订阅者的完整列表，并将每个EndpointARN与设备的EndpointARN进行比较。我认为这不可能是正确的方式

订阅主题

// 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;

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);
    }
}

findTopicARNForTopic方法已经迭代主题列表，并将后缀与主题名称进行比较。我真的不知道这是否是最好的做法

取消订阅主题

// 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;

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);
    }
}

---

现在，我要求提供整个订户列表，并将EndpointARN与设备的EndpointARN进行比较。我使用以下方法获得订阅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;
}

使用此方法，我将设备从主题中删除：

- (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);
        }
    }
}

---

您还可以将SubscriptionArn存储在SubscriberResponse中，并在UnSubscribeRequest中使用此值。

现在，我要求提供整个订户列表，并将EndpointARN与设备的EndpointARN进行比较。我将在等待8个小时后发布代码…我也遇到了同样的问题，并且在订阅列表中进行了迭代。我担心的是安全问题：我们如何确保只有当前设备被取消订阅？是否有可能其他设备被取消订阅？另外：回答您的解决方案和新代码可能会对其他设备有所帮助。这是不好的。订阅请求返回的arn只是“待定确认”。只有在其他服务确认订阅后，才能创建实际的ARN。@b您可以使用ReturnSubscriptionArn布尔值返回实际的主题ARN。此外，apns/fcm订阅的afaik无需确认。