在 .net core 1.0 中解析 AWS SNS 通知

Question

我有一个VisualStudio17无服务器应用程序项目，正在使用.net core Web Api。

我想确认我的 SNS 订阅，但我遇到一个问题，即 AWS 发送标头content-type设置为text/plain; charset=UTF-8的 POST 请求，而正文为 JSON。

以下是他们文档中的示例请求：

POST / HTTP/1.1
x-amz-sns-message-type: Notification
x-amz-sns-message-id: da41e39f-ea4d-435a-b922-c6aae3915ebe
x-amz-sns-topic-arn: arn:aws:sns:us-west-2:123456789012:MyTopic
x-amz-sns-subscription-arn: arn:aws:sns:us-west-2:123456789012:MyTopic:2bcfbf39-05c3-41de-beaa-fcfcc21c8f55
Content-Length: 761
Content-Type: text/plain; charset=UTF-8
Host: ec2-50-17-44-49.compute-1.amazonaws.com
Connection: Keep-Alive
User-Agent: Amazon Simple Notification Service Agent
{
"Type" : "Notification",
"MessageId" : "da41e39f-ea4d-435a-b922-c6aae3915ebe",
"TopicArn" : "arn:aws:sns:us-west-2:123456789012:MyTopic",
"Subject" : "test",
"Message" : "test message",
"Timestamp" : "2012-04-25T21:49:25.719Z",
"SignatureVersion" : "1",
"Signature" : "EXAMPLElDMXvB8r9R83tGoNn0ecwd5UjllzsvSvbItzfaMpN2nk5HVSw7XnOn/49IkxDKz8YrlH2qJXj2iZB0Zo2O71c4qQk1fMUDi3LGpij7RCW7AW9vYYsSqIKRnFS94ilu7NFhUzLiieYr4BKHpdTmdD6c0esKEYBpabxDSc=",
"SigningCertURL" : "https://sns.us-west-2.amazonaws.com/SimpleNotificationService-f3ecfb7224c7233fe7bb5f59f96de52f.pem",
"UnsubscribeURL" : "https://sns.us-west-2.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-west-2:123456789012:MyTopic:2bcfbf39-05c3-41de-beaa-fcfcc21c8f55"
} 

内容类型：文本、正文 JSON。这使得解析变得相当困难，而且简单

public void Post([FromBody] string t) // or dynamic t for the matter

不起作用并引发Request was short circuited at action filter 'Microsoft.AspNetCore.Mvc.ModelBinding.UnsupportedContentTypeFilter'.异常。

我错过了什么吗？他们为什么要这样做，我该如何使用它？

Answer 1

我通过向JsonInputFormatter应该格式化的格式添加text/plain，使它像我在这个答案中描述的那样工作。

public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(config =>
{
foreach (var formatter in config.InputFormatters)
{
if (formatter.GetType() == typeof(JsonInputFormatter))
((JsonInputFormatter)formatter).SupportedMediaTypes.Add(
MediaTypeHeaderValue.Parse("text/plain"));
}
});
...
}

Answer 2

现在，Amazon SNS 中有一个内置解决方案，它刚刚启动了对从主题传送的 HTTP 消息的自定义Content-Type标头的支持。这是发布帖子：https://aws.amazon.com/about-aws/whats-new/2023/03/amazon-sns-content-type-request-headers-http-s-notifications/

您必须修改 Amazon SNS 订阅的DeliveryPolicy属性，将headerContentType属性设置为application/json或支持的任何其他值。您可以在此处找到支持的所有值：https://docs.aws.amazon.com/sns/latest/dg/sns-message-delivery-retries.html#creating-delivery-policy

{
"healthyRetryPolicy": {
"minDelayTarget": 1,
"maxDelayTarget": 60,
"numRetries": 50,
"numNoDelayRetries": 3,
"numMinDelayRetries": 2,
"numMaxDelayRetries": 35,
"backoffFunction": "exponential"
},
"throttlePolicy": {
"maxReceivesPerSecond": 10
},
"requestPolicy": {
"headerContentType": "application/json"
}
}

您可以通过调用Subscribe或SetSubscriptionAttributesAPI 操作来设置DeliveryPolicy属性：

• https://docs.aws.amazon.com/sns/latest/api/API_Subscribe.html
• https://docs.aws.amazon.com/sns/latest/api/API_SetSubscriptionAttributes.html

或者，您也可以使用 AWS CloudFormation 来设置此策略，并使用AWS::SNS::Subscription资源。