Miniapi of. Net7 (special section): NET7 Preview3

.NET7 The third preview version of has been released , It also brings mini api Update , This time we bring the routing filter , And mvc Version of action Filter similarity . Specific view https://devblogs.microsoft.com/dotnet/asp-net-core-updates-in-dotnet-7-preview-3/

Use the official code , Can't run , Such and such questions , Consider the following code , Directly report the exception of null reference .

app.MapGet("/data0/{no}", (string no) =>
{
    Console.WriteLine($"Get In the method ：no={no}");
    return new Data { No = no, Name = "test" + DateTime.Now };


}).AddFilter((RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next) =>
    {
        var no = (string?)context.Parameters[0];
        Console.WriteLine($"Get Before the method ：no={no}");
        if (no != null && !no.StartsWith("NO"))
        {
            return new ValueTask<object?>("no is error!");
        }
        var result = next(context);
        if (result.IsCompleted)
        {
            Console.WriteLine($"Get After the method ： result ={result.Result}");
        }
        return result;
    });

After a while of tossing and turning , Finally, I started running normally , Need to put map The method of writing can be written independently . At the same time, there are three ways to use filters , The soup does not change the dressing , The essence is the same .

var builder = WebApplication.CreateBuilder(args);


var app = builder.Build();


Data GetData(string no)
{
    Console.WriteLine($"Get In the method ：no={no}");
    return new Data { No = no, Name = "test" + DateTime.Now };
};
// The first way 
app.MapGet("/data1/{no}", GetData)
    .AddFilter((RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next) =>
    {
        var no = (string?)context.Parameters[0];
        Console.WriteLine($"Get Before the method ：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 After the method ： result ={result.Result}");
        }
        return result;
    });


string AddTest(Data data)
{
    Console.WriteLine($"Post In the method ：no={data.No}");
    return "OK";
}
app.MapPost("/data1", AddTest)
    .AddFilter((RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next) =>
    {
        var data = (Data?)context.Parameters[0];
        Console.WriteLine($"Post Before the method ：data={data}");
        var result = next(context);
        if (result.IsCompleted)
        {
            Console.WriteLine($"Post After the method ： result ={result.Result}");
        }
        return result;
    });
// The second way 
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);
    };
});
// The third way 
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; }
}