????????????ASP.NET Core????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????HTTP????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????HTTP?????????

??????
??????HttpApplication
?????? FeatureCollection
?????? HostingApplication
??????HttpContext
?????? DefaultHttpContext
?????? HostingApplication
?????? ??????
???????????????
?????? HttpListenerServer
?????? ServerFactory
?????? ??????

ASP.NET Core???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????HttpApplication???????????????????????????????????????Server???HttpApplication?????????????????????5????????????Server??????????????????HTTP???????????????HttpApplication???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????HttpApplication?????????????????????????????????????????????

?????????????????????????????????IHttpApplication<TContext>????????????????????????HttpApplication???????????????TContext?????????????????????????????????????????????HttpApplication??????????????????Server???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

   1: public interface IHttpApplication<TContext>

   2: {

   3:     TContext CreateContext(IFeatureCollection contextFeatures); 

   4:     Task ProcessRequestAsync(TContext context);

   5:     void DisposeContext(TContext context, Exception exception);

   6: }

????????????????????????CreateContext???????????????????????????IFeatureCollection??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Vaue???????????????????????????Key??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Get??????????????????????????????????????????????????????????????????????????????Set??????????????????FeatureCollection??????????????????????????????????????????????????????

   1: public interface IFeatureCollection

   2: {

   3:     TFeature Get<TFeature>();

   4:     void Set<TFeature>(TFeature instance);

   5: }

   6:?? 

   7: public class FeatureCollection : IFeatureCollection

   8: {

   9:     private ConcurrentDictionary<Type, object> features = new ConcurrentDictionary<Type, object>();

  10:?? 

  11:     public TFeature Get<TFeature>()

  12:     {

  13:         object feature;

  14:         return features.TryGetValue(typeof(TFeature), out feature) 

  15:             ? (TFeature)feature 

  16:             : default(TFeature);

  17:     }

  18:?? 

  19:     public void Set<TFeature>(TFeature instance)

  20:     {

  21:         features[typeof(TFeature)] = instance;

  22:     }

  23: }

?????????????????????HttpApplication?????????????????? HostingApplication????????????????????????????????????????????????????????????????????????IHttpApplication<Context>???????????????Context??????????????????????????????????????????????????????Context????????????HttpContext???????????????????????????????????????HTTP????????????????????????????????????Context?????????Scope???StartTimestamp????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Logger???BeginScope??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

   1: public class HostingApplication : IHttpApplication<Context>

   2: {

   3:     //??????????????????

   4: }

   5:?? 

   6: public class Context

   7: {

   8:     public HttpContext     HttpContext { get; set; }

   9:     public IDisposable     Scope { get; set; }

  10:     public long            StartTimestamp { get; set; }

  11: }

???????????????UML????????????HttpApplication?????????????????????/?????????????????????????????????????????????????????????IHttpApplication<TContext>??????HttpApplication????????????????????????????????????HttpApplication????????????????????????????????????????????????????????????????????????????????????????????????????????????HTTP??????????????????????????????????????????????????????????????????IFeatureCollection????????????FeatureCollection?????????????????????????????????ASP.NET Core ???????????????HttpApplication?????????HostingApplication???????????????????????????????????????Context?????????Context??????????????????HttpContext???????????????????????????????????????????????????

??????????????????HTTP?????????????????????HttpContext??????ASP .NET Core??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????HttpContext?????????????????????????????????????????????HTTP????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Requst???Response?????????

   1: public abstract class HttpContext

   2: {

   3:     public abstract HttpRequest     Request { get; }

   4:     public abstract HttpResponse    Response { get; }

   5: }

????????????????????????HttpRequest???HttpResponse?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????HttpRequest????????????????????????????????????Url???????????????HttpResponse??????????????????????????????????????????????????????OutputStream?????????????????????ContentType????????????????????????StatusCode??????

   1: public abstract class HttpRequest

   2: {

   3:     public abstract Uri Url { get; }

   4: }

   5:?? 

   6: public abstract class HttpResponse

   7: {

   8:     public abstract Stream     OutputStream { get; }

   9:     public abstract string     ContentType { get; set; }

  10:     public abstract int        StatusCode { get; set; }

  11:?? 

  12:     public void WriteFile(string fileName, string contentType)

  13:     {

  14:         if (File.Exists(fileName))

  15:         {

  16:             byte[] content         = File.ReadAllBytes(fileName);

  17:             this.ContentType       = contentType;

  18:             this.OutputStream.Write(content, 0, content.Length);

  19:         }

  20:         this.StatusCode = 404;

  21:     }

  22: }

ASP.NET Core???????????????HttpContext??????????????????DefaultHttpContext??????????????????DefaultContext??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????DefaultHttpContext?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????FeatureCollection?????????????????????

??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????FeatureCollection?????????????????????????????????DefaultHttpContext??????????????????????????????????????????DefaultHttpContext???????????????????????????????????????????????????????????????????????????????????????????????????????????????

????????????DefaultHttpContext?????????????????????HTTP????????????????????????DefaultHttpContext???????????????????????????????????????????????????????????????DefaultHttpContext????????????IFeatureCollection???????????????HttpContextFeatures????????????????????????????????????????????????????????????HTTP????????????????????????FeatureCollection????????????????????????????????????????????????????????????DefaultHttpContext??????????????????????????????????????????????????????DefaultHttpRequst???HttpResponse?????????

   1: public class DefaultHttpContext : HttpContext

   2: { 

   3:    public IFeatureCollection HttpContextFeatures { get;}

   4:?? 

   5:     public DefaultHttpContext(IFeatureCollection httpContextFeatures)

   6:     {

   7:         this.HttpContextFeatures = httpContextFeatures;

   8:         this.Request             = new DefaultHttpRequest(this);

   9:         this.Response            = new DefaultHttpResponse(this);

  10:     }   

  11:     public override HttpRequest     Request { get; }

  12:     public override HttpResponse    Response { get; }

  13: }

??????????????????HTTP?????????????????????????????????DefaultHttpContext??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????IHttpRequestFeature???IHttpResponseFeature????????????HttpRequest???HttpResponse??????????????????????????????

   1: public interface IHttpRequestFeature

   2: {

   3:     Uri Url { get; }

   4: }

   5:?? 

   6: public interface IHttpResponseFeature

   7: {

   8:     Stream     OutputStream { get; }

   9:     string     ContentType { get; set; }

  10:     int        StatusCode { get; set; }

  11: }

?????????DefaultHttpContext?????????????????????????????????DefaultHttpRequest???DefaultHttpResponse????????????????????????????????????FeatureCollection????????????HttpRequestFeature???HttpResponseFeature??????????????????????????????????????????????????????????????????

   1: public class DefaultHttpRequest : HttpRequest

   2: {

   3:     public IHttpRequestFeature RequestFeature { get; }

   4:     public DefaultHttpRequest(DefaultHttpContext context)

   5:     {

   6:         this.RequestFeature = context.HttpContextFeatures.Get<IHttpRequestFeature>();

   7:     }

   8:     public override Uri Url

   9:     {

  10:         get { return this.RequestFeature.Url; }

  11:     }

  12: }

  13:?? 

  14: public class DefaultHttpResponse : HttpResponse

  15: {

  16:     public IHttpResponseFeature ResponseFeature { get; }

  17:?? 

  18:     public override Stream OutputStream

  19:     {

  20:         get { return this.ResponseFeature.OutputStream; }

  21:     }

  22:?? 

  23:     public override string ContentType

  24:     {

  25:         get { return this.ResponseFeature.ContentType; }

  26:         set { this.ResponseFeature.ContentType = value; }

  27:     }

  28:?? 

  29:     public override int StatusCode

  30:     {

  31:         get { return this.ResponseFeature.StatusCode; }

  32:         set { this.ResponseFeature.StatusCode = value; }

  33:     }

  34:?? 

  35:     public DefaultHttpResponse(DefaultHttpContext context)

  36:     {

  37:         this.ResponseFeature = context.HttpContextFeatures.Get<IHttpResponseFeature>();

  38:     }

  39: }

????????????DefaultHttpContext???????????????????????????????????????????????????????????????HttpApplication?????????HostingApplication??????????????????????????????????????????????????????HttpContext??????????????????????????????????????????????????????????????????????????????????????????????????????RequestDelegate??????????????????????????????HttpApplication????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Application?????????RequestDelegate?????????

   1: public class HostingApplication : IHttpApplication<Context>

   2: {

   3:     public RequestDelegate Application { get; }

   4:?? 

   5:     public HostingApplication(RequestDelegate application)

   6:     {

   7:         this.Application = application;

   8:     }

   9:?? 

  10:     public Context CreateContext(IFeatureCollection contextFeatures)

  11:     {

  12:         HttpContext httpContext = new DefaultHttpContext(contextFeatures);

  13:         return new Context

  14:         {

  15:             HttpContext     = httpContext,

  16:             StartTimestamp     = Stopwatch.GetTimestamp()

  17:         };

  18:     }

  19:?? 

  20:     public void DisposeContext(Context context, Exception exception) 

  21:        => context.Scope?.Dispose();

  22:?? 

  23:     public Task ProcessRequestAsync(Context context) 

  24:        => this.Application(context.HttpContext);

  25: }

?????????????????????HostingApplication??????????????????????????????????????????????????????????????????RequestDelegate???????????????????????????????????????????????????????????????ProcessRequestAsync????????????????????????????????????????????????????????????CreateContext?????????????????????????????????????????????????????????HTTP????????????FeatureCollection??????????????????DefaultHttpContext??????????????????????????????Context?????????????????????DisposeContext?????????????????????????????????Context?????????Scope?????????Dispose???????????????Scope????????????????????????????????????Context??????????????????Scope????????????????????????

????????????????????????UML?????????HTTP????????????????????????/??????????????????????????????????????????????????????????????????????????????HTTP????????????????????????HttpContext???????????????????????????HttpContext???????????????????????????????????????????????????????????????????????????HttpRequest???HttpResponse?????????ASP.NET Core ???????????????HttpContext?????????DefaultHttpContext?????????????????????????????????????????????DefaultHttpRequst???DefaultHttpResponse???????????????DefaultHttpContext?????????????????????HTTP??????????????????????????????????????????????????????????????????????????????????????????IHttpRequestFeature???IHttpResponseFeature?????????DefaultHttpRequst???DefaultHttpResponse????????????????????????????????????

?????????????????????????????????IServer??????????????????????????????????????????????????????????????????????????????????????????Start??????????????????Start?????????????????????????????????????????????????????????????????????HTTP??????????????????????????????????????????????????????HttpApplication???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????HttpApplication????????????????????????????????????????????????????????????

   1: public interface IServer

   2: {

   3:     void Start<TContext>(IHttpApplication<TContext> application);

   4: }

???????????????????????????????????????????????????????????????????????????HttpListenerServer??????????????????????????????????????????????????????????????????HttpListener?????????????????????????????????????????????????????????????????????????????????????????????????????????HttpListenerServer??????????????????HttpListener???????????????????????????????????????????????????????????????????????????????????????https://localhost:3721/?????????

   1: public class HttpListenerServer : IServer

   2: {

   3:     public HttpListener Listener { get; }

   4:?? 

   5:     public HttpListenerServer(string url)

   6:     {

   7:         this.Listener = new HttpListener();

   8:         this.Listener.Prefixes.Add(url ?? "https://localhost:3721/");

   9:     }

  10:?? 

  11:     public void Start<TContext>(IHttpApplication<TContext> application)

  12:     {

  13:         this.Listener.Start();

  14:         while (true)

  15:         {

  16:             HttpListenerContext httpListenerContext = this.Listener.GetContext();

  17:?? 

  18:             HttpListenerContextFeature feature = new HttpListenerContextFeature(httpListenerContext);

  19:             FeatureCollection contextFeatures = new FeatureCollection();

  20:             contextFeatures.Set<IHttpRequestFeature>(feature);

  21:             contextFeatures.Set<IHttpResponseFeature>(feature);

  22:             TContext context = application.CreateContext(contextFeatures);

  23:?? 

  24:             application.ProcessRequestAsync(context)

  25:                 .ContinueWith(_ => httpListenerContext.Response.Close())

  26:                 .ContinueWith(_ => application.DisposeContext(context, _.Exception));

  27:         }

  28:     }

  29: }

???Start????????????????????????HttpListener???Start?????????????????????????????????HTTP?????????HTTP?????????????????????????????????????????????HttpListenerContext??????????????????HttpListener???GetContext??????????????????????????????????????????????????????????????????????????????HttpListenerContextFeature????????????????????????????????????IHttpRequestFeature???IHttpResponseFeature??????????????????FeatureCollection???????????????????????????HttpApplication??????????????????????????????CreateContext?????????????????????????????????ProcessRequestAsync????????????????????????????????????????????????????????????????????????????????????????????????????????????HttpApplication?????????DisposeContext????????????????????????????????????

???WebHost???????????????????????????????????????????????????????????????????????????????????????????????????ServerFactory????????????ServerFactory?????????????????????IServerFactory???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????CreateServer????????????????????????HttpListenerServer???????????????HttpListenerServerFactory????????????????????????????????????????????????????????????CreateServer??????????????????HttpListenerServer?????????

   1: public interface IServerFactory

   2: {

   3:     IServer CreateServer();

   4: }

   5:?? 

   6: public class HttpListenerServerFactory : IServerFactory

   7: {

   8:     private string listenUrl;

   9:?? 

  10:     public HttpListenerServerFactory(string listenUrl = null)

  11:     {

  12:         this.listenUrl = listenUrl?? "https://localhost:3721/";

  13:     }

  14:?? 

  15:     public IServer CreateServer()

  16:     {

  17:         return new HttpListenerServer(listenUrl);

  18:     }

  19: }

???????????????UML????????????????????????????????????/????????????????????????????????????IServer???????????????????????????????????????????????????????????????????????????????????????????????????HttpListenerServer????????????HttpListener????????????????????????????????????HttpListenerServer??????????????????HTTP????????????????????????????????????HTTP?????????????????????????????????HttpListenerContextFeature?????????HttpListenerContextFeature?????????????????????????????????????????????????????????IHttpRequestFeature???IHttpResponseFeature???HostingApplication??????????????????HttpListenerContextFeature???????????????DefaultHttpContext?????????

??

????????????????????????HTTP??????
?????????????????????????????????????????????????????????????????????????????????
????????????????????????HTTP?????????
???????????????????????????????????????