在 ASP.Net Core 中添加中间件到 Pipe

Question

Previously in ASP.Net I would have written a Generic Http Handler to do this but it looks like in ASP.Net Core you write Middleware.

I am trying to get my Middleware to be called when the page GetUser is requested.

I've tried to understand how from this page https://learn.microsoft.com/en-us/as.net/core/fundamentals/middleware/?view=as.netcore-7.0 - but have only got so far.

The Middleware code is as follows;

public class GetUser
{
    public GetUser(RequestDelegate next)
    {
        // note this is a handler so no need to store the next
    }

    public async Task Invoke(HttpContext context)
    {
        String response = String.Empty;

        try
        {
            response = GenerateResponse(context);

            context.Response.ContentType = "text/plain";
            context.Response.StatusCode = 200;

            await context.Response.WriteAsync(response);
        }
        catch ( System.Exception ex)
        {
            response = ex.Message;
        }
    }

    public String GenerateResponse(HttpContext context)
    {
        String response = "";

        response = "a response";

        return response;
    }

     
}

public static class GetUserExtension
{
    public static IApplicationBuilder UseGetUser(this IApplicationBuilder builder)
    {
        return builder.UseMiddleware<GetUser>();
    }

}

In Program.cs I have added the following line;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorPages();

var app = builder.Build();

app.Map("/GetUser",GetUserExtension.UseGetUser(builder));

Which fails because builder is a WebApplicationBuilder and not IApplicationBuilder.

So how can I use app.Map so that it calls GetUserExtension.UseGetUser when the GetUser Page is requested.

Answer 1

Make sure your middleware is correctly placed in the program.cs file, which when it is called contains all the resources that it needs to return the request. This is not much but hopes this helps.