1: public class DefaultFilesMiddleware

   2: {

   3:     public DefaultFilesMiddleware(RequestDelegate next, IHostingEnvironment hostingEnv, IOptions<DefaultFilesOptions> options);

   4:     public Task Invoke(HttpContext context);

   5: }

   6:  

   7: public class DefaultFilesOptions : SharedOptionsBase

   8: {

   9:     public IList<string> DefaultFileNames { get; set; }

  10:  

  11:     public DefaultFilesOptions() : this(new SharedOptions()){}

  12:     public DefaultFilesOptions(SharedOptions sharedOptions) : base(sharedOptions)

  13:     {

  14:         this.DefaultFileNames = new List<string> { "default.htm", "default.html", "index.htm", "index.html" };

  15:     }    

  16: }

   1: public class DefaultFilesMiddleware

   2: {

   3:     private RequestDelegate         _next;

   4:     private DefaultFilesOptions     _options;

   5:   

   6:     public DefaultFilesMiddleware(RequestDelegate next, IHostingEnvironment env, IOptions<DefaultFilesOptions> options)

   7:     {

   8:         _next                     = next;

   9:         _options                  = options.Value;

  10:         _options.FileProvider     = _options.FileProvider ?? env.WebRootFileProvider;

  11:     }

  12:  

  13:     public async Task Invoke(HttpContext context)

  14:     {

  15:         //只处理GET和HEAD请求

  16:         if (!new string[] { "GET", "HEAD" }.Contains(context.Request.Method,StringComparer.OrdinalIgnoreCase))

  17:         {

  18:             await _next(context);

  19:             return;

  20:         }

  21:  

  22:         //检验当前路径是否与注册的请求路径相匹配

  23:         PathString path = new PathString(context.Request.Path.Value.TrimEnd('/') + "/");

  24:         PathString subpath;

  25:         if (!path.StartsWithSegments(_options.RequestPath, out subpath))

  26:         {

  27:             await _next(context);

  28:             return;

  29:         }

  30:  

  31:         //检验目标目录是否存在

  32:         if (!_options.FileProvider.GetDirectoryContents(subpath).Exists)

  33:         {

  34:             await _next(context);

  35:             return;

  36:         }

  37:  

  38:         //检验当前目录是否包含默认文件

  39:         foreach (var fileName in _options.DefaultFileNames)

  40:         {

  41:             if (_options.FileProvider.GetFileInfo($"{subpath}{fileName}").Exists)

  42:             {

  43:                 //如果当前路径不以"/"作为后缀，会响应一个针对“标准”URL的重定向

  44:                 if (!context.Request.Path.Value.EndsWith("/"))

  45:                 {

  46:                     context.Response.StatusCode = 302;

  47:                     context.Response.GetTypedHeaders().Location = new Uri(path.Value + context.Request.QueryString);

  48:                     return;

  49:                 }

  50:                 //将针对目录的URL更新为针对默认文件的URL

  51:                 

  52:             }

  53:         }

  54:         await _next(context);

  55:     }

  56: }