我正在使用带有服务总线触发器的 Azure 函数应用程序来读取服务总线并处理服务总线消息的内容。服务总线接收 JSON 序列化对象，然后我将 JSON 消息反序列化回函数应用程序中的对象。但是，由于某种原因，每当有东西被发送到服务总线时，触发器就会触发两次，一次是 JSON 消息，另一次是包含文本“服务总线消息”的消息。
我不知道是什么导致了第二条消息，所以我想出的只是反序列化服务总线消息，当它因“服务总线消息”而失败时，我只会捕获异常并忽略它。但是，我认为这不是处理此问题的正确方法，并且 JSON 反序列化中的实际错误将被忽略。处理第二条消息的正确方法是什么？
示例代码：
using Newtonsoft.Json;
public static void Run(string myQueueItem, ILogger log, out SendGridMessage mailMessage)
{
MyClass myObject = null;
try
{
myObject = JsonConvert.DeserializeObject<MyClass>(myQueueItem);
// do stuff
}
catch (JsonException je)
{
// ignore this exception
}
catch (Exception e)
{
// handle the other exceptions and send an alert
}
}
编辑：我在原帖中遗漏的一件事是我也有一个 SendGrid 输出。我不明白为什么这会对触发器产生任何影响，这就是我忽略它的原因。但是，我现在添加它以防万一它可能是出于某种奇怪的原因。
编辑 2：添加了突出问题的完整工作代码
// Sender
using System;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Azure.ServiceBus;
using Newtonsoft.Json;
namespace myapp
{
class Program
{
static void Main(string[] args) => MainAsync().GetAwaiter().GetResult();
static async Task MainAsync()
{
string serviceBusConnectionString = "<your servicebus connectionstring>";
string queueName = "<your queue name>";
IQueueClient queueClient = new QueueClient(serviceBusConnectionString, queueName);
string messageBody = JsonConvert.SerializeObject(new Test());
var message = new Message(Encoding.UTF8.GetBytes(messageBody));
await queueClient.SendAsync(message);
await queueClient.CloseAsync();
}
class Test
{
public string Text { get; set; } = "test";
}
}
}
// Receiver
#r "Newtonsoft.Json"
using System;
using System.Threading.Tasks;
using Newtonsoft.Json;
public static void Run(string myQueueItem, ILogger log)
{
try
{
Test test = JsonConvert.DeserializeObject<Test>(myQueueItem);
log.LogInformation($"C# ServiceBus queue trigger function processed message: {test.Text}");
}
catch (Exception e)
{
log.LogInformation($"Exception: {e.Message}");
}
}
class Test
{
public string Text { get; set; } = "test";
}
结果：
2019-11-04T08:38:10.544 [Information] Executing 'Functions.test' (Reason='This function was programmatically called via the host APIs.', Id=06e10006-baa6-430f-b5db-9a5eae5c154c)
2019-11-04T08:38:10.659 [Information] Exception: Unexpected character encountered while parsing value: S. Path '', line 0, position 0. // This here is caused by "Service bus message"
2019-11-04T08:38:10.659 [Information] Executed 'Functions.test' (Succeeded, Id=06e10006-baa6-430f-b5db-9a5eae5c154c)
2019-11-04T08:39:02.582 [Information] Executing 'Functions.test' (Reason='New ServiceBus message detected on 'test'.', Id=5d7622a7-cc8d-44c9-8720-626fdbb8cabb)
2019-11-04T08:39:02.583 [Information] Trigger Details: MessageId: 13bba779fd524fa1a0098acd6634aded, DeliveryCount: 1, EnqueuedTime: 11/4/2019 8:39:02 AM, LockedUntil: 11/4/2019 8:39:07 AM
2019-11-04T08:39:02.584 [Information] C# ServiceBus queue trigger function processed message: test // This here is the actual message
2019-11-04T08:39:02.584 [Information] Executed 'Functions.test' (Succeeded, Id=5d7622a7-cc8d-44c9-8720-626fdbb8cabb)
