// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using Microsoft.AspNetCore.HostFiltering;

namespace Microsoft.AspNetCore.Builder
{
    /// <summary>
    /// Extension methods for the HostFiltering middleware.
    /// </summary>
    public static class HostFilteringBuilderExtensions
    {
        /// <summary>
        /// Adds middleware for filtering requests by allowed host headers. Invalid requests will be rejected with a
        /// 400 status code.
        /// </summary>
        /// <param name="app">The <see cref="IApplicationBuilder"/> instance this method extends.</param>
        /// <returns>The original <see cref="IApplicationBuilder"/>.</returns>
        public static IApplicationBuilder UseHostFiltering(this IApplicationBuilder app)
        {
            if (app == null)
            {
                throw new ArgumentNullException(nameof(app));
            }

            app.UseMiddleware<HostFilteringMiddleware>();

            return app;
        }
    }
}
