[ASP.NET Core Middleware 存取 SPA 網頁資源] 搭配 SPA 前端框架使用，將網頁導向至 index.html #dotnet #angular

SpaMiddleware.cs

using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;

namespace DemoApp.Middleware
{
    /// <summary>SPA 中介程序</summary>
    public class SpaMiddleware
    {
        private readonly RequestDelegate _next;

        /// <summary>建構式</summary>
        public SpaMiddleware(RequestDelegate next)
        {
            _next = next;
        }
        /// <summary>任務調用</summary>
        /// <remarks>使用 index.html 存取網頁資源</remarks>
        public async Task Invoke(HttpContext context)
        {
            await _next.Invoke(context);

            if (context.Response.StatusCode == 404 &&                       // 該資源不存在
                !System.IO.Path.HasExtension(context.Request.Path.Value) && // 網址最後沒有帶副檔名
                !context.Request.Path.Value.StartsWith("/api"))             // 網址不是 /api 開頭（不是發送 API 需求）
            {
                context.Request.Path = "/index.html";                       // 將網址改成 /index.html
                context.Response.StatusCode = 200;                          // 並將 HTTP 狀態碼修改為 200 成功

                await _next.Invoke(context);
            }
        }
    }
    /// <summary>SPA 中介程序的擴充方法</summary>
    public static class SpaExtensions
    {
        /// <summary>存取 SPA 網頁資源</summary>
        /// <param name="builder">中介程序建構器</param>
        public static IApplicationBuilder UseSpaStaticFiles(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<SpaMiddleware>();
        }
    }
}

Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using DemoApp.Middleware;

namespace DemoApp
{
    public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();
            Configuration = builder.Build();
        }

        public IConfigurationRoot Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddMvc();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            // 存取 SPA 網頁資源
            app.UseSpaStaticFiles();

            app.UseDefaultFiles();
            app.UseStaticFiles();

            app.UseMvc();
        }
    }
}