mcs/class/System.Web/System.Web.Caching/OutputCacheModule.cs

   1 //
   2 // System.Web.Caching.OutputCacheModule
   3 //
   4 // Authors:
   5 //  Jackson Harper (jackson@ximian.com)
   6 //
   7 // (C) 2003 Novell, Inc (http://www.novell.com)
   8 //
   9
  10 using System.Web;
  11 using System.Web.Util;
  12 using System.Collections;
  13
  14 namespace System.Web.Caching {
  15
  16         internal sealed class OutputCacheModule : IHttpModule {
  17
  18                 private CacheItemRemovedCallback response_removed;
  19
  20                 public OutputCacheModule ()
  21                 {
  22                 }
  23
  24                 public void Dispose ()
  25                 {
  26                 }
  27
  28                 public void Init (HttpApplication app)
  29                 {
  30                         app.AddOnResolveRequestCacheAsync (
  31                                 new BeginEventHandler (OnBeginRequestCache),
  32                                 new EndEventHandler (OnEndRequestCache));
  33
  34                         app.AddOnUpdateRequestCacheAsync (
  35                                 new BeginEventHandler (OnBeginUpdateCache),
  36                                 new EndEventHandler (OnEndUpdateCache));
  37
  38                         response_removed = new CacheItemRemovedCallback (OnRawResponseRemoved);
  39                 }
  40
  41                 IAsyncResult OnBeginRequestCache (object o, EventArgs args, AsyncCallback cb, object data)
  42                 {
  43                         HttpApplication app = (HttpApplication) o;
  44                         HttpContext context = app.Context;
  45
  46                         string vary_key = context.Request.FilePath;
  47                         CachedVaryBy varyby = context.Cache [vary_key] as CachedVaryBy;
  48                         string key;
  49                         CachedRawResponse c;
  50
  51                         if (varyby == null)
  52                                 goto leave;
  53
  54                         key = varyby.CreateKey (vary_key, context);
  55                         c = context.Cache [key] as CachedRawResponse;
  56
  57                         if (c != null) {
  58
  59                                 context.Response.ClearContent ();
  60                                 context.Response.BinaryWrite (c.GetData (), 0, c.ContentLength);
  61
  62                                 context.Response.ClearHeaders ();
  63                                 c.DateHeader.Value = TimeUtil.ToUtcTimeString (DateTime.Now);
  64                                 context.Response.SetCachedHeaders (c.Headers);
  65
  66                                 context.Response.StatusCode = c.StatusCode;
  67                                 context.Response.StatusDescription = c.StatusDescription;
  68
  69                                 app.CompleteRequest ();
  70                         } else if (c != null) {
  71                                 context.Cache.Remove (key);
  72                         }
  73
  74                 leave:
  75                         HttpAsyncResult result = new HttpAsyncResult (cb,this);
  76                         result.Complete (true, o, null);
  77
  78                         return result;
  79                 }
  80
  81                 void OnEndRequestCache (IAsyncResult result)
  82                 {
  83                 }
  84
  85                 IAsyncResult OnBeginUpdateCache (object o, EventArgs args, AsyncCallback cb, object data)
  86                 {
  87                         HttpApplication app = (HttpApplication) o;
  88                         HttpContext context = app.Context;
  89                         HttpAsyncResult result;
  90
  91                         if (context.Response.IsCached && context.Response.StatusCode == 200 &&
  92                             !context.Trace.IsEnabled)
  93                                 DoCacheInsert (context);
  94
  95                         result = new HttpAsyncResult (cb, this);
  96                         result.Complete (true, o, null);
  97                         return result;
  98                 }
  99
 100                 void OnEndUpdateCache (IAsyncResult result)
 101                 {
 102                 }
 103
 104                 private void DoCacheInsert (HttpContext context)
 105                 {
 106                         string vary_key = context.Request.FilePath;
 107                         string key;
 108                         CachedVaryBy varyby = context.Cache [vary_key] as CachedVaryBy;
 109                         CachedRawResponse prev = null;
 110                         bool lookup = true;
 111
 112                         if (varyby == null) {
 113                                 varyby = new CachedVaryBy (context.Response.Cache, vary_key);
 114                                 context.Cache.InsertPrivate (vary_key, varyby, null,
 115                                                 Cache.NoAbsoluteExpiration,
 116                                                 Cache.NoSlidingExpiration,
 117                                                 CacheItemPriority.Normal, null);
 118                                 lookup = false;
 119                         }
 120
 121                         key = varyby.CreateKey (vary_key, context);
 122
 123                         if (lookup)
 124                                 prev = context.Cache [key] as CachedRawResponse;
 125
 126                         if (prev == null) {
 127                                 CachedRawResponse c = context.Response.GetCachedResponse ();
 128                                 string [] files = new string [] { vary_key };
 129                                 string [] keys = new string [] { vary_key };
 130                                 bool sliding = context.Response.Cache.Sliding;
 131
 132                                 context.Cache.InsertPrivate (key, c, new CacheDependency (files, keys),
 133                                                 (sliding ? Cache.NoAbsoluteExpiration :
 134                                                                 context.Response.Cache.Expires),
 135                                                 (sliding ? TimeSpan.FromSeconds (
 136                                                         context.Response.Cache.Duration) :
 137                                                                 Cache.NoSlidingExpiration),
 138                                                 CacheItemPriority.Normal, response_removed);
 139                                 c.VaryBy = varyby;
 140                                 varyby.ItemList.Add (key);
 141                         }
 142                 }
 143
 144                 private void OnRawResponseRemoved (string key, object value, CacheItemRemovedReason reason)
 145                 {
 146                         CachedRawResponse c = (CachedRawResponse) value;
 147
 148                         c.VaryBy.ItemList.Remove (key);
 149                         if (c.VaryBy.ItemList.Count != 0)
 150                                 return;
 151
 152                         Cache cache = HttpRuntime.Cache;
 153                         cache.Remove (c.VaryBy.Key);
 154                 }
 155         }
 156 }
 157