在ASP.NET 5 MVC 6应用程序中使用Web API

Question

我有一个包含自定义错误页面的ASP.NET 5 MVC 6应用程序.如果我现在想在/api路径下添加API控制器,我使用Map方法看到了以下模式:

public class Startup
{
    public void Configure(IApplicationBuilder application)
    {
        application.Map("/api", ConfigureApi);

        application.UseStatusCodePagesWithReExecute("/error/{0}");

        application.UseMvc();
    }

    private void ConfigureApi(IApplicationBuilder application)
    {
        app.Run(async (context) =>
        {
            await context.Response.WriteAsync("Hello World from API!");
        });
    }
}

上面的代码在/api路径下创建了一个全新的独立应用程序.这很棒,因为您不希望Web API有自定义错误页面,但确实希望它们适用于您的MVC应用程序.

我是否正确地认为在ConfigureApi中,我应该再次添加MVC以便我可以使用控制器？另外,如何针对此子应用程序专门配置服务,选项和过滤器？有没有办法ConfigureServices(IServiceCollection services)为这个子应用程序？

private void ConfigureApi(IApplicationBuilder app)
{
    application.UseMvc();
}

Answer 1

以下是如何使用启用“条件中间件执行”的小扩展方法：

public class Startup {
    public void Configure(IApplicationBuilder app) {
        app.UseWhen(context => !context.Request.Path.StartsWithSegments(new PathString("/api")), branch => {
            // Register the status code middleware, but only for non-API calls.
            branch.UseStatusCodePagesWithReExecute("/error/{0}");
        });

        app.UseMvc();
   }
}


public static class AppBuilderExtensions {
    public static IApplicationBuilder UseWhen(this IApplicationBuilder app,
        Func<HttpContext, bool> condition, Action<IApplicationBuilder> configuration) {
        if (app == null) {
            throw new ArgumentNullException(nameof(app));
        }

        if (condition == null) {
            throw new ArgumentNullException(nameof(condition));
        }

        if (configuration == null) {
            throw new ArgumentNullException(nameof(configuration));
        }

        var builder = app.New();
        configuration(builder);

        return app.Use(next => {
            builder.Run(next);

            var branch = builder.Build();

            return context => {
                if (condition(context)) {
                    return branch(context);
                }

                return next(context);
            };
        });
    }
}