[英]ASP.NET Core 2.1 - Memory cache - value set in middleware cannot be accessed by controller
我在Asp.Net Core 2.1 Webapi項目中使用IMemoryCache臨時存儲從RabbitMq通道接收的一些數據。 我在定制的中間件中有一個頻道監聽器。 但是,當我嘗試從控制器訪問緩存中的數據時,其中沒有數據。 我正在使用Autofac作為我的DI框架。
如果將值設置為控制器中的內存緩存,則可以從其他類中獲取該值,例如與此控制器關聯的服務(也在Autofac DI中注冊)。
我的實現如下:
services.AddMemoryCache();
然后使用中間件作為
app.UseMiddleware<RabbitMqConsumerMiddleware>();
app.UseCors("default")
.UseAuthentication()
.UseMvc();`
我的Autofac注冊如下:
這是我的Autofac注冊
public IServiceProvider ConfigureServices(IServiceCollection services)
{
RabbitMqConfiguration rabbitMqConfiguration = new RabbitMqConfiguration();
Configuration.GetSection("RabbitMq").Bind(rabbitMqConfiguration);
services.AddSingleton(rabbitMqConfiguration);
services.AddMvcCore()
.AddAuthorization()
.AddJsonFormatters()
.SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
.AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix)
.AddDataAnnotationsLocalization()
.AddControllersAsServices()
.AddApiExplorer();
services.AddRabbitMq(rabbitMqConfiguration);
services.AddMemoryCache();
ContainerBuilder builder = new ContainerBuilder();
builder.Populate(services);
IContainer container = builder.Build();
return new AutofacServiceProvider(container);
}
在中間件中,我有
public RabbitMqConsumerMiddleware(RequestDelegate next, IMemoryCache memoryCache, RabbitMqConfiguration configuration, IModel messageBodyReceiverChannel) { _next = next; _memoryCache = memoryCache; _configuration = configuration; _messageBodyReceiverChannel = messageBodyReceiverChannel; } public async Task Invoke(HttpContext context) { bool isMessageBodyReceiverConsumerExist = _memoryCache.TryGetValue("message-body-receiver-consumer", out EventingBasicConsumer messageBodyReceiverConsumer); if (!isMessageBodyReceiverConsumerExist) { var messageBodyReceiverConsumer = new EventingBasicConsumer(_messageBodyReceiverChannel); messageBodyReceiverConsumer.Received += (ch, ea) => { MessageBody messageBody = JsonConvert.DeserializeObject<MessageBody>(Encoding.Default.GetString(ea.Body)); if (_memoryCache.TryGetValue("Message Body", out List<MessageBody> cacheMessageBodies)) { cacheMessageBodies.Add(messageBody); } else { _memoryCache.Set("Message Body", new List<MessageBody> { messageBody }); } }; _memoryCache.Set("message-body-receiver-consumer", messageBodyReceiverConsumer); } _messageBodyReceiverChannel.BasicConsume(_configuration.MessageReceiverQueue, false, messageBodyReceiverConsumer); await _next(context); }
messageBody
來自RabbitMq的位置
在控制器中我有
[Authorize] [Route("[controller]")] [ApiController] public class MessageBodyController : ControllerBase { private readonly IApplicationService<Dto.MessageBody> _messageBodyPresenter; private readonly IMemoryCache _memoryCache; public MessageBodyController(IApplicationService<Dto.MessageBody> messageBodyPresenter, IMemoryCache memoryCache) { _messageBodyPresenter = messageBodyPresenter; _memoryCache = memoryCache; } [HttpGet] [Route("Stop")] public IActionResult Stop() { ((MessageBodyPresenter)_messageBodyPresenter).Stop(); return Ok(); } }
但是_memoryCache
始終為空。
我在中間件中放置了一個斷點,並確認已將數據設置為緩存。
我是否以錯誤的方式使用內存緩存? 謝謝
不知道您的完整配置,我想一個問題可能是您在Mvc中間件之后注冊了新的中間件。
您的注冊應如下所示:
app.UseMiddleware<RabbitMqConsumerMiddleware>();
app.UseMvc();
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