使用Simple Injector将依赖项注入OWIN中间件并按Web请求

问题描述

我正在尝试找出如何将所有依赖项最好地注入到我为Web API应用程序编写的自定义OWIN中间件中。一个简单的例子就是我正在使用的DbContext。我有一些可能需要根据请求进行查询的中间件。我遇到的问题是，我希望我的DbContext具有WebApiRequestLifestyle范围。我的DbContext是这样注册的：

I am trying to work out how to best inject all of my dependencies into the custom OWIN Middleware I have written for a Web API Application. A simple example would be the DbContext I am using. I have some middleware that needs to potentially query based on the request. The issue I have is that I want my DbContext to otherwise have a WebApiRequestLifestyle scope. My DbContext is registered as such:

container.Register<MobileDbContext>(Lifestyle.Scoped);

显然，这不起作用：

container.Options.DefaultScopedLifestyle = new WebApiRequestLifestyle();

因为我在中间件中需要使用MobileDbContext，例如：

Because I need the MobileDbContext in my Middleware using something like:

app.CreatePerOwinContext(() =>
{
    return container.GetInstance<MobileDbContext>();
};

我尝试了混合生活方式，但这也没有用，因为我认为中间件不是从技术上讲，这可能属于范围内的生活方式。我想它可能更接近单例。

I tried a hybrid lifestyle, but that also didn't work because I don't think the Middleware is technically something that can fall under a "scoped" lifestyle. It is probably closer to a singleton, I would think.

是否有更好的方法来设计我的应用以避免

Is there a better way to design my app to avoid this problem or address it with some sort of custom scoped lifestyle?

推荐答案

显示了如何在范围内包装OWIN请求的示例：

The documentation shows an example of how to wrap an OWIN request in a scope:

public void Configuration(IAppBuilder app) {
    app.Use(async (context, next) => {
        using (AsyncScopedLifedtyle.BeginScope (container)) {
            await next();
        }
    });
}

这是在执行上下文范围内包装OWIN请求。现在您要做的就是将执行竞赛范围设置为默认范围内的生活方式，如下所示：

What this does is wrapping an OWIN request in an execution context scope. All you have to do now is make the execution contest scope the default scoped lifestyle as follows:

container.Options.DefaultScopedLifestyle = new AsyncScopedLifestyle();

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