我有一个普通的。net web API项目,为了学习事件驱动的架构,我开始了一个小项目。我是公共交通的新手,我使用他们的文档编写了代码。我使用bus.Send(command)命令和bus.Publish(event)事件。当我发送命令时,我在命令处理程序中接收到所有期望的值,但在发布时,一些属性为空。当我出于某种原因发布消息时,Id和EntityThatTookAction为空,但填充了其他属性。我不明白这种行为的原因。我错过什么了吗?如果你能帮我解决这个问题,我将非常感激。
配置services.AddMassTransit(massTransitConfig =>
{
massTransitConfig.AddConsumer<UserEventConsumer>();
massTransitConfig.AddConsumer<UserCommandHandler>();
massTransitConfig.AddConsumer<TodoListEventConsumer>();
massTransitConfig.AddConsumer<TodoListCommandHandler>();
massTransitConfig.UsingRabbitMq((context, rabbitMqConfig) =>
{
rabbitMqConfig.Host(new Uri(busConfig["Url"]), h =>
{
h.Username(busConfig["Username"]);
h.Password(busConfig["Password"]);
});
rabbitMqConfig.ReceiveEndpoint(nameof(UserEventConsumer), cfg =>
{
cfg.PurgeOnStartup = true;
cfg.PrefetchCount = 10;
cfg.Bind<UserCreatedEvent>();
cfg.Bind<UserUpdatedEvent>();
cfg.Bind<UserDeletedEvent>();
cfg.ConfigureConsumer(context, typeof(UserEventConsumer));
});
rabbitMqConfig.ReceiveEndpoint(nameof(UserCommandHandler), cfg =>
{
cfg.PurgeOnStartup = true;
cfg.PrefetchCount = 10;
cfg.Bind<CreateUserCommand>();
cfg.Bind<UpdateUserCommand>();
cfg.Bind<DeleteUserCommand>();
cfg.ConfigureConsumer(context, typeof(UserCommandHandler));
EndpointConvention.Map<CreateUserCommand>(cfg.InputAddress);
EndpointConvention.Map<UpdateUserCommand>(cfg.InputAddress);
EndpointConvention.Map<DeleteUserCommand>(cfg.InputAddress);
});
rabbitMqConfig.ReceiveEndpoint(nameof(TodoListEventConsumer), cfg =>
{
cfg.PurgeOnStartup = true;
cfg.PrefetchCount = 10;
cfg.ConfigureConsumer(context, typeof(TodoListEventConsumer));
});
rabbitMqConfig.ReceiveEndpoint(nameof(TodoListCommandHandler), cfg =>
{
cfg.PurgeOnStartup = true;
cfg.PrefetchCount = 10;
cfg.ConfigureConsumer(context, typeof(TodoListCommandHandler));
EndpointConvention.Map<CreateTodoListCommand>(cfg.InputAddress);
EndpointConvention.Map<UpdateTodoListCommand>(cfg.InputAddress);
EndpointConvention.Map<DeleteTodoListCommand>(cfg.InputAddress);
});
});
});
事件public class UserCreatedEvent : IBaseEvent
{
public string Id { get; }
public string Message { get; }
public string EntityThatTookAction { get; }
public DateTimeOffset CreatedOn { get; }
public EntityType EntityType { get; }
public Guid CorrelationId { get; }
public UserCreatedEvent(string entityId, string entity, EntityType entityType, Guid correlationId, DateTimeOffset createdOn)
{
Id = entityId;
EntityThatTookAction = entity;
CreatedOn = createdOn;
EntityType = entityType;
CorrelationId = correlationId;
Message = "User list created";
}
}
界面public interface IBaseEvent : CorrelatedBy<Guid>
{
public string Id { get; }
public string Message { get;}
public string EntityThatTookAction { get;}
public DateTimeOffset CreatedOn { get;}
public EntityType EntityType { get; }
}
发布var message = new UserCreatedEvent(entityId, entity, EntityType.User, correlationId, DateTimeOffset.UtcNow);
await _bus.Publish(message);
您没有发布可以工作的命令契约,但是我会查找两者之间的任何差异,以查看可能发生的情况。可能你的属性上没有{ get; private set; }
,但我不记得是否需要。我认为它需要是可设置的,以便反序列化工作。如果你使用。net 5,你可以指定{ get; init; }
。
另外,我清理了您的总线配置,您很可能不想使用PurgeOnStartup
,而EndpointConvention
是不受欢迎的。
services.AddMassTransit(massTransitConfig =>
{
massTransitConfig.AddConsumer<UserEventConsumer>();
massTransitConfig.AddConsumer<UserCommandHandler>();
massTransitConfig.AddConsumer<TodoListEventConsumer>();
massTransitConfig.AddConsumer<TodoListCommandHandler>();
massTransitConfig.UsingRabbitMq((context, rabbitMqConfig) =>
{
rabbitMqConfig.Host(new Uri(busConfig["Url"]), h =>
{
h.Username(busConfig["Username"]);
h.Password(busConfig["Password"]);
});
rabbitMqConfig.ReceiveEndpoint(nameof(UserEventConsumer), cfg =>
{
cfg.PrefetchCount = 10;
cfg.ConfigureConsumer<UserEventConsumer>(context);
});
rabbitMqConfig.ReceiveEndpoint(nameof(UserCommandHandler), cfg =>
{
cfg.PrefetchCount = 10;
cfg.ConfigureConsumer<UserCommandHandler>(context);
});
rabbitMqConfig.ReceiveEndpoint(nameof(TodoListEventConsumer), cfg =>
{
cfg.PrefetchCount = 10;
cfg.ConfigureConsumer<TodoListEventConsumer>(context);
});
rabbitMqConfig.ReceiveEndpoint(nameof(TodoListCommandHandler), cfg =>
{
cfg.PrefetchCount = 10;
cfg.ConfigureConsumer<TodoListCommandHandler>(context);
});
});
});