WebApi:如何使用IoC实现每个请求每个操作的DbSession?

我们现有的数据库部署有一个“主”和一个只读副本。使用ASP。NET的Web API2和IoC容器,我想创建控制器操作,其属性(或缺少属性)指示该请求将使用哪个数据库连接(请参阅下面的控制器和服务使用情况)。。。

public MyController :  ApiController
{
    public MyController(IService1 service1, IService2 service2) { ... }

    // this action just needs the read only connection
    // so no special attribute is present
    public Foo GetFoo(int id)
    {
        var foo = this.service1.GetFoo(id);
        this.service2.GetSubFoo(foo);
        return foo;
    }

    // This attribute indicates a readwrite db connection is needed
    [ReadWrteNeeded]
    public Foo PostFoo(Foo foo)
    {
        var newFoo = this.service1.CreateFoo(foo);
        return newFoo;
    }
}

public Service1 : IService1
{
    // The dbSession instance injected here will be
    // based off of the action invoked for this request
    public Service1(IDbSession dbSession) { ... }

    public Foo GetFoo(int id) 
    { 
        return this.dbSession.Query<Foo>(...);
    }

    public Foo CreateFoo(Foo newFoo)
    {
        this.dbSession.Insert<Foo>(newFoo);
        return newFoo;
    }
}

然而,我不确定如何为请求生成IDbSession实例的类型,以关闭匹配控制器动作的指示器属性(或缺少)。我假设我需要创建一个ActionFilter,它将查找指示符属性,并使用该信息识别或创建正确类型的IDbSession(只读或读写)。但是,如何确保创建的IDbSession的生命周期由容器管理?你不在运行时将实例注入容器,那将是愚蠢的。我知道过滤器在启动时创建一次(使其成为单例),所以我无法将值注入过滤器的向量。

思想?

更新:

我开始使用史蒂文提出的制作DbSessionProxy的建议。这很管用,但我真的在寻找一个纯粹的国际奥委会解决方案。必须使用HttpContext和/或(在我的情况下)请求。我只是觉得这里有点脏。所以,如果我不得不脏的话,我最好一路走,对吗?

注射 将当前HttpRequestMessage导入服务(这很重要)。以下是我所做的。。。

IoC容器设置:

For<IDbSession>().Use(() => DbSession.ReadOnly()).Named("ReadOnly");
For<IDbSession>().Use(() => DbSession.ReadWrite()).Named("ReadWrite");
For<ISampleService>().Use<SampleService>();

public class DbAccessAttribute : ActionFilterAttribute
{
    private readonly DbSessionType dbType;

    public DbAccessAttribute(DbSessionType dbType)
    {
        this.dbType = dbType;
    }

    public override bool AllowMultiple => false;

    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        var container = (IContainer)actionContext.GetService<IContainer>();
        var dbSession = this.dbType == DbSessionType.ReadOnly ?
                container.GetInstance<IDbSession>("ReadOnly") :
                container.GetInstance<IDbSession>("ReadWrite");

        // if this is a ReadWrite HttpRequest start an Request long
        // database transaction
        if (this.dbType == DbSessionType.ReadWrite)
        {
            dbSession.Begin();
        }

        actionContext.Request.Properties["DbSession"] = dbSession;
    }

    public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
    {
        var dbSession = (IDbSession)actionExecutedContext.Request.Properties["DbSession"];
        if (this.dbType == DbSessionType.ReadWrite)
        {
            // if we are responding with 'success' commit otherwise rollback
            if (actionExecutedContext.Response != null &&
                actionExecutedContext.Response.IsSuccessStatusCode &&
                actionExecutedContext.Exception == null)
            {
                dbSession.Commit();                    
            }
            else
            {
                dbSession.Rollback();
            }
        }
    }
}

更新的服务1:

public class Service1: IService1
{
    private readonly HttpRequestMessage request;
    private IDbSession dbSession;

    public SampleService(HttpRequestMessage request)
    {
        // WARNING: Never attempt to access request.Properties[Constants.RequestProperty.DbSession]
        // in the ctor, it won't be set yet.
        this.request = request;
    }

    private IDbSession Db => (IDbSession)request.Properties["DbSession"];

    public Foo GetFoo(int id) 
    { 
        return this.Db.Query<Foo>(...);
    }

    public Foo CreateFoo(Foo newFoo)
    {
        this.Db.Insert<Foo>(newFoo);
        return newFoo;
    }
}