.NET7的第三个预览版发布了，同样带来了mini api的更新，这次带来了路由过滤器，与mvc版的action 过滤器相似。具体见https://devblogs.microsoft.com/dotnet/asp-net-core-updates-in-dotnet-7-preview-3/
用官方的代码，跑不起来，这样那样的问题，比如下面的代码，直接报空引用的异常。
app.MapGet("/data0/{no}", (string no) => { Console.WriteLine($"Get方法中：no={no}"); return new Data { No = no, Name = "test" + DateTime.Now }; }).AddFilter((RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next) => { var no = (string?)context.Parameters[0]; Console.WriteLine($"Get方法前：no={no}"); if (no != null && !no.StartsWith("NO")) { return new ValueTask<object?>("no is error!"); } var result = next(context); if (result.IsCompleted) { Console.WriteLine($"Get方法后：结果={result.Result}"); } return result; });
经过一阵折腾，终于正常的跑了起来，需要把map的方法独立出来写才可以。同时这里使用了三种方式来使用过滤器，换汤不换药，本质一样。
var builder = WebApplication.CreateBuilder(args); var app = builder.Build(); Data GetData(string no) { Console.WriteLine($"Get方法中：no={no}"); return new Data { No = no, Name = "test" + DateTime.Now }; }; //第一种方式 app.MapGet("/data1/{no}", GetData) .AddFilter((RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next) => { var no = (string?)context.Parameters[0]; Console.WriteLine($"Get方法前：no={no}"); if (no != null && !no.StartsWith("NO")) { return new ValueTask<object?>("no is error!"); } var result = next(context); if (result.IsCompleted) { Console.WriteLine($"Get方法后：结果={result.Result}"); } return result; }); string AddTest(Data data) { Console.WriteLine($"Post方法中：no={data.No}"); return "OK"; } app.MapPost("/data1", AddTest) .AddFilter((RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next) => { var data = (Data?)context.Parameters[0]; Console.WriteLine($"Post方法前：data={data}"); var result = next(context); if (result.IsCompleted) { Console.WriteLine($"Post方法后：结果={result.Result}"); } return result; }); //第二种方式 app.MapGet("/data2/{no}", GetData) .AddFilter((RouteHandlerContext routeHandlerContext, RouteHandlerFilterDelegate next) => { return (context) => { var no = (string?)context.Parameters[0]; if (no != null && !no.StartsWith("NO")) { return new ValueTask<object?>("no is error!"); } return next(context); }; }); //第三种方式 app.MapGet("/data3/{name}", GetData).AddFilter<MyFilter>(); app.Run(); public class MyFilter : IRouteHandlerFilter { public ValueTask<object?> InvokeAsync(RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next) { var no = (string?)context.Parameters[0]; if (no != null && !no.StartsWith("NO")) { return new ValueTask<object?>("no is error!"); } return next(context); } } public record Data { public string No { get; set; } public string Name { get; set; } }
