Azure WebJob ProcessQueueMessage無法讀取CloudQueueMessage

Question

總之，我使用CloudQueueMessage參數類型，通過WebJobs SDK的ProcessQueueMessage機制將一個Azure Web作業鏈接到CloudQueue。當通過QueueTrigger觸發時，這給了我一個FunctionInvocationException。

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詳細

項被使用AddMessageAsync方法成功添加到CloudQueue：

await queue.AddMessageAsync(new CloudQueueMessage(JsonConvert.SerializeObject(myObject))); 

並且在隊列中作爲我的對象的預期JSON表示出現（從消息在Cloud Explorer中的文本預覽）：

{"EmailAddress":"example@mail.com", 
"Subject":"Test", 
"TemplateId":"00-00-00-00-00", 
"Model":{"PropertyName1":"Test1","PropertyName2":"Test2"} 
} 

然而，當ProcessQueueMessage方法被觸發：

public static async void ProcessQueueMessage(
    [QueueTrigger(queueName)] CloudQueueMessage message, TextWriter log) 

...我得到一個FunctionInvocationException：

Microsoft.Azure.WebJobs.Host.FunctionInvocationException: Exception while executing function: Functions.ProcessQueueMessage ---> System.InvalidOperationException: Exception binding parameter 'message' ---> System.ArgumentNullException: String reference not set to an instance of a String. 
Parameter name: s 
at System.Text.Encoding.GetBytes(String s) 
at Microsoft.WindowsAzure.Storage.Queue.CloudQueueMessage.get_AsBytes() in c:\Program Files (x86)\Jenkins\workspace\release_dotnet_master\Lib\Common\Queue\CloudQueueMessage.Common.cs:line 146 
at Microsoft.Azure.WebJobs.Host.PropertyHelper.CallPropertyGetter[TDeclaringType,TValue](Func`2 getter, Object this) 
at Microsoft.Azure.WebJobs.Host.PropertyHelper.GetValue(Object instance) 
at Microsoft.Azure.WebJobs.Host.Bindings.BindingDataProvider.GetBindingData(Object value) 
at Microsoft.Azure.WebJobs.Host.Queues.Triggers.UserTypeArgumentBindingProvider.UserTypeArgumentBinding.BindAsync(IStorageQueueMessage value, ValueBindingContext context) 
at Microsoft.Azure.WebJobs.Host.Queues.Triggers.QueueTriggerBinding.<BindAsync>d__0.MoveNext() 
--- End of stack trace from previous location where exception was thrown --- 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at Microsoft.Azure.WebJobs.Host.Triggers.TriggeredFunctionBinding`1.<BindCoreAsync>d__7.MoveNext() 
--- End of inner exception stack trace --- 
at Microsoft.Azure.WebJobs.Host.Executors.DelayedException.Throw() 
at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<ExecuteWithWatchersAsync>d__31.MoveNext() 
--- End of stack trace from previous location where exception was thrown 

這似乎表明，message參數無法讀取JSON入CloudQueueMessage對象......但它並不表示它是我控制的東西。

有沒有人有任何建議，爲什麼這可能會發生？

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版本信息

Microsoft.Azure.Webjobs 1.1.1

WindowsAzure.Storage 6.2.2預覽

DNX 4.5。1

背景

Troy Hunt - Web Job primer

MSDN - How to... article

Answer 1

改變你的ProcessQueueMessage接受一個字符串（這是你真正傳遞什麼樣的CloudQueuMessage），然後採取和它反序列化到對象：

public static async void ProcessQueueMessage(
    [QueueTrigger(queueName)] string message, TextWriter log) 
{ 
    JsonConvert.DeserializeObject<YourObjectType>(json); 
} 

或事件好，如果這是一個POCO對象，那麼所有你所要做的就是，與其使用：

public static async void ProcessQueueMessage 
(
    [QueueTrigger(queueName)] YourObjectType message, 
    TextWriter log 
) 
{  //.... } 

更新： 雖然這將是很好得到的CloudQueueMessage對象整個事情，但要獲得在CloudQueueMessage中發送的屬性可以將以下參數添加到webjob方法中：

public static async void ProcessQueueMessage(
     [QueueTrigger(queueName)] string logMessage, 
     DateTimeOffset expirationTime, 
     DateTimeOffset insertionTime, 
     DateTimeOffset nextVisibleTime, 
     string id, 
     string popReceipt, 
     int dequeueCount, 
     string queueTrigger, 
     CloudStorageAccount cloudStorageAccount, 
     TextWriter logger) 
    { 
     logger.WriteLine(
      "logMessage={0}\n" + 
     "expirationTime={1}\ninsertionTime={2}\n" + 
      "nextVisibleTime={3}\n" + 
      "id={4}\npopReceipt={5}\ndequeueCount={6}\n" + 
      "queue endpoint={7} queueTrigger={8}", 
      logMessage, expirationTime, 
      insertionTime, 
      nextVisibleTime, id, 
      popReceipt, dequeueCount, 
      cloudStorageAccount.QueueEndpoint, 
      queueTrigger); 
    }