public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        //This middleware is used reports app runtime errors in development environment.
        app.UseDeveloperExceptionPage();
    }
    else
    {
        //This middleware is catches exceptions thrown in production environment.
        app.UseExceptionHandler("/Error");
        // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
        app.UseHsts(); //adds the Strict-Transport-Security header.
    }
    //This middleware is used to redirects HTTP requests to HTTPS.
    app.UseHttpsRedirection();
    //This middleware is used to returns static files and short-circuits further request processing.
    app.UseStaticFiles();
    //This middleware is used to route requests.
    app.UseRouting();
    //This middleware is used to authorizes a user to access secure resources.
    app.UseAuthorization();
    //This middleware is used to add Razor Pages endpoints to the request pipeline.
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapRazorPages();
    });
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.Use(async (context, next) =>
    {
        await context.Response.WriteAsync("Before Invoke from 1st app.Use()\n");
        await next();
        await context.Response.WriteAsync("After Invoke from 1st app.Use()\n");
    });
    app.Use(async (context, next) =>
    {
        await context.Response.WriteAsync("Before Invoke from 2nd app.Use()\n");
        await next();
        await context.Response.WriteAsync("After Invoke from 2nd app.Use()\n");
    });
    app.Run(async (context) =>
    {
        await context.Response.WriteAsync("Hello from 1st app.Run()\n");
    });
    // the following will never be executed
    app.Run(async (context) =>
    {
        await context.Response.WriteAsync("Hello from 2nd app.Run()\n");
    });
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.Map("/m1", HandleMapOne);
    app.Map("/m2", appMap => {
        appMap.Run(async context =>
        {
            await context.Response.WriteAsync("Hello from 2nd app.Map()");
        });
    });
    app.Run(async (context) =>
    {
        await context.Response.WriteAsync("Hello from app.Run()");
    });
}
private static void HandleMapOne(IApplicationBuilder app)
{
    app.Run(async context =>
    {
        await context.Response.WriteAsync("Hello from 1st app.Map()");
    });
}

public class LogURLMiddleware
{
    private readonly RequestDelegate _next;
    private readonly ILogger<LogURLMiddleware> _logger;
    public LogURLMiddleware(RequestDelegate next, ILoggerFactory loggerFactory)
    {
        _next = next;
        _logger = loggerFactory?.CreateLogger<LogURLMiddleware>() ??
        throw new ArgumentNullException(nameof(loggerFactory));
    }
    public async Task InvokeAsync(HttpContext context)
    {
        _logger.LogInformation($"Request URL: {Microsoft.AspNetCore.Http.Extensions.UriHelper.GetDisplayUrl(context.Request)}");
        await this._next(context);
    }
}

public static class LogURLMiddlewareExtensions
{
    public static IApplicationBuilder UseLogUrl(this IApplicationBuilder app)
    {
        return app.UseMiddleware<LogURLMiddleware>();
    }
}

app.UseLogUrl();

app.UseDirectoryBrowser(new DirectoryBrowserOptions
{
    FileProvider = new PhysicalFileProvider(Path.Combine(Directory.GetCurrentDirectory(), "wwwroot", "images")),
    RequestPath = "/images"
});