仅当使用 rest API 队列不可用时才在 azure 队列中创建队列

Question

我只想在队列在 Azure 存储中不可用时创建队列。我正在使用此 PutMessage 方法在队列中创建消息。这种方法工作正常，但问题出在我身上，我需要附加 CreateQueue 方法。

我的 createqueue 方法也工作正常，但我无法确定需要添加的位置，因为当 PutMessage 调用 request.GetResponse() 时，如果队列是错误的。谢谢

public static void PutMessage(String queueName, String message)
        {
            String requestMethod = "POST";

            String urlPath = $"{queueName}/messages";

            String storageServiceVersion = "2017-11-09";
            String dateInRfc1123Format = DateTime.UtcNow.ToString("R", CultureInfo.InvariantCulture);

            String messageText = $"<QueueMessage><MessageText>{message}</MessageText></QueueMessage>";
            UTF8Encoding utf8Encoding = new UTF8Encoding();
            Byte[] messageContent = utf8Encoding.GetBytes(messageText);
            Int32 messageLength = messageContent.Length;

            String canonicalizedHeaders = String.Format(
                    "x-ms-date:{0}\nx-ms-version:{1}",
                    dateInRfc1123Format,
                    storageServiceVersion);
            String canonicalizedResource = $"/{StorageAccountName}/{urlPath}";
            String stringToSign = $"{requestMethod}\n\n\n{messageLength}\n\n\n\n\n\n\n\n\n{canonicalizedHeaders}\n{canonicalizedResource}";
                    
            String authorizationHeader = CreateAuthorizationHeader(stringToSign);

            Uri uri = new Uri("https://" + StorageAccountName + ".queue.Azure.com/" + urlPath);
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
            request.Method = requestMethod;
            request.Headers.Add("x-ms-date", dateInRfc1123Format);

            request.Headers.Add("x-ms-version", storageServiceVersion);

            request.Headers.Add("Authorization", authorizationHeader);
            request.ContentLength = messageLength;

            using (Stream requestStream = request.GetRequestStream())
            {
                requestStream.Write(messageContent, 0, messageLength);
            }

            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
            {
                String requestId = response.Headers["x-ms-request-id"];
            }
        }

Answer 1

您可以将以下代码放在 try/catch 块中并检查 WebException.

using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
    String requestId = response.Headers["x-ms-request-id"];
}

如果队列不存在，那么您将收到 404 (Not Found) 响应状态的错误。在这种情况下，您应该尝试创建队列，一旦收到成功的响应，您应该再次调用您的放置消息。

您的代码将类似于：


try
{
    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    {
        String requestId = response.Headers["x-ms-request-id"];
    }
}
catch (WebException exception)
{
    HttpWebResponse response = (HttpWebResponse) exception.Response;
    if (response.StatusCode == HttpStatusCode.NotFound)
    {
        //Call your create queue method here...
        CreateQueue(queueName);
        //Once the operation is successful, call PutMessage again.
        PutMessage(queueName, message);
    }
    else 
    {
        throw;
    }
}

请注意，您也可以获得其他异常，但是在此操作的上下文中，我们不会尝试处理它们，而只是重新抛出这些异常。

仅当使用 rest API 队列不可用时才在 azure 队列中创建队列

Create queue in azure queue only if queue not available using rest API

api

rest

azure

azure-storage

azure-storage-queues