辛格尔顿每调用上下文（网络请求）在Unity

问题描述

前几天我曾与ASP.Net线程这​​个问题。我想有每个Web请求一个单独的对象。我确实需要这对我的工作单位。我想，这样的身份地图是有效的通过了要求每个实例化Web请求的工作单元。这样，我可以用一个IoC透明地注入我​​自己IUnitOfWork我的库类，我可以使用相同的实例来查询，然后更新我的实体。

A few days ago I had this issue with ASP.Net threading. I wanted to have a singleton object per web request. I actually need this for my unit of work. I wanted to instantiate a unit of work per web request so that identity map is valid through out the request. This way I could use an IoC to inject my own IUnitOfWork to my repository classes transparently, and I could use the same instance to query and then update my entities.

由于我使用的统一，我错误地使用了PerThreadLifeTimeManager。我很快意识到，ASP.Net线程模型不支持我想acheive什么。基本上，它采用了theadpool并回收线程，这意味着我得到每线程间的UnitOfWork！不过，我想是每web请求一个工作单元。

Since I am using Unity, I mistakenly used PerThreadLifeTimeManager. I soon realised that ASP.Net threading model does not support what I want to acheive. Basically it uses a theadpool and recycles threads, and that means that I get one UnitOfWork per thread!! However, what I wanted was one unit of work per web request.

google搜索的一点给我的。这正是我想要的;除了这是很容易acheive团结一部分。

A bit of googling gave me this great post. That was exactly what I wanted; except for the unity part which was quite easy to acheive.

这是我的执行PerCallContextLifeTimeManager团结：

This is my implementation for PerCallContextLifeTimeManager for unity:

public class PerCallContextLifeTimeManager : LifetimeManager
{
    private const string Key = "SingletonPerCallContext";

    public override object GetValue()
    {
        return CallContext.GetData(Key);
    }

    public override void SetValue(object newValue)
    {
        CallContext.SetData(Key, newValue);
    }

    public override void RemoveValue()
    {
    }
}

当然，我用这个来我工作的单位有一个类似的code寄存器：

And of course I use this to register my unit of work with a code similar to this:

unityContainer
            .RegisterType<IUnitOfWork, MyDataContext>(
            new PerCallContextLifeTimeManager(),
            new InjectionConstructor());

希望这样可以节省别人一点时间。

Hope it saves someone a bit of time.

推荐答案

巧妙的解决办法，但LifetimeManager的每个实例应该使用一个唯一的密钥，而不是一个常量：

Neat solution, but each instance of LifetimeManager should use a unique key rather than a constant:

private string _key = string.Format("PerCallContextLifeTimeManager_{0}", Guid.NewGuid());

否则，如果您有PerCallContextLifeTimeManager注册了多个对象，他们共享同一个密钥来访问CallContext中，你不会得到你的预期目标了。

Otherwise if you have more than one object registered with PerCallContextLifeTimeManager, they're sharing the same key to access CallContext, and you won't get your expected object back.

另外值得一实施RemoveValue确保对象清理：

Also worth implementing RemoveValue to ensure objects are cleaned up:

public override void RemoveValue()
{
     CallContext.FreeNamedDataSlot(_key);
}

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