c# - 有什么方法可以使 ITicketStore 有范围吗？

Question

我正在使用 ITicketStore按照这个article .每当需要执行任何数据库操作时，都会在此创建 DbContext。

在我的代码中，不是通过 using() 语法创建 DbContext，而是通过构造函数注入(inject)。在代码投入生产之前，一切都运行良好。当流量增加时开始出现以下异常。

• System.InvalidOperationException 在上一个操作完成之前在此上下文中启动了第二个操作。
• Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException

这可能是因为 ITicketStore 是单例并且使用在多个线程之间共享相同 DbContext 实例的 DI 注入(inject) DbContext。

我更改了代码以通过 using() 创建 DbContext 实例，现在它工作正常。

但我正在尝试通过 DI 注入(inject)来找出使 DbContext 工作的任何方法。

Answer 1

我是这样做的

//in Startup.cs ConfigureServices method  

//I tried using the PostConfigure methods, but it didn't to work for me
services.TryAddEnumerable(ServiceDescriptor.Singleton<IPostConfigureOptions<CookieAuthenticationOptions>, PostConfigureCookieAuthenticationOptionsTicketStore>());

    //This sets the store to the options.
    public class PostConfigureCookieAuthenticationOptionsTicketStore : IPostConfigureOptions<CookieAuthenticationOptions>
    {
        private readonly SingletonTicketStore _store;

        public PostConfigureCookieAuthenticationOptionsTicketStore(SingletonTicketStore store) => _store = store;

        public void PostConfigure(string name, CookieAuthenticationOptions options) => options.SessionStore = _store;
    }
    
    //This implemenation is singleton compatible
    public class SingletonTicketStore : ITicketStore
    {
        private readonly IServiceProvider _services;

        public SingletonTicketStore(IServiceProvider services)
        {
            _services = services;
        }

        public async Task RemoveAsync(string key) => await WithScopeAsync(s => s.RemoveAsync(key));
        public async Task RenewAsync(string key, AuthenticationTicket ticket) => await WithScopeAsync(s => s.RenewAsync(key, ticket));
        public async Task<AuthenticationTicket> RetrieveAsync(string key) => await WithScopeAsync(s => s.RetrieveAsync(key));
        public async Task<string> StoreAsync(AuthenticationTicket ticket) => await WithScopeAsync(s => s.StoreAsync(ticket));

        private async Task WithScopeAsync(Func<ITicketStore, Task> action) => await WithScopeAsync(async t => { await action(t); return true; });
        private async Task<T> WithScopeAsync<T>(Func<ITicketStore, Task<T>> action)
        {
            //This opens a new scope, allowing you to use scoped dependencies
            using (var scope = _services.CreateScope())
            {
                //don't forget to await the result here, of stuff (dbcontext) could be disposed otherwise
                return await action(scope.ServiceProvider.GetRequiredService<ITicketStore>());
            }
        }
    }

    public class ScopedTicketStore : ITicketStore
    {
        //your implementation
    }

希望这有帮助；)