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.IO;
  11 using System.Web;
  12 using System.Web.Util;
  13 using System.Collections;
  14
  15 namespace System.Web.Caching {
  16
  17         internal sealed class OutputCacheModule : IHttpModule {
  18
  19                 private CacheItemRemovedCallback response_removed;
  20
  21                 public OutputCacheModule ()
  22                 {
  23                 }
  24
  25                 public void Dispose ()
  26                 {
  27                 }
  28
  29                 public void Init (HttpApplication app)
  30                 {
  31                         app.AddOnResolveRequestCacheAsync (
  32                                 new BeginEventHandler (OnBeginRequestCache),
  33                                 new EndEventHandler (OnEndRequestCache));
  34
  35                         app.AddOnUpdateRequestCacheAsync (
  36                                 new BeginEventHandler (OnBeginUpdateCache),
  37                                 new EndEventHandler (OnEndUpdateCache));
  38
  39                         response_removed = new CacheItemRemovedCallback (OnRawResponseRemoved);
  40                 }
  41
  42                 IAsyncResult OnBeginRequestCache (object o, EventArgs args, AsyncCallback cb, object data)
  43                 {
  44                         HttpApplication app = (HttpApplication) o;
  45                         HttpContext context = app.Context;
  46
  47                         string vary_key = context.Request.FilePath;
  48                         CachedVaryBy varyby = context.Cache [vary_key] as CachedVaryBy;
  49                         string key;
  50                         CachedRawResponse c;
  51
  52                         if (varyby == null)
  53                                 goto leave;
  54
  55                         key = varyby.CreateKey (vary_key, context);
  56                         c = context.Cache [key] as CachedRawResponse;
  57
  58                         if (c != null) {
  59
  60                                 context.Response.ClearContent ();
  61                                 context.Response.BinaryWrite (c.GetData (), 0, c.ContentLength);
  62
  63                                 context.Response.ClearHeaders ();
  64                                 c.DateHeader.Value = TimeUtil.ToUtcTimeString (DateTime.Now);
  65                                 context.Response.SetCachedHeaders (c.Headers);
  66
  67                                 context.Response.StatusCode = c.StatusCode;
  68                                 context.Response.StatusDescription = c.StatusDescription;
  69
  70                                 app.CompleteRequest ();
  71                         } else if (c != null) {
  72                                 context.Cache.Remove (key);
  73                         }
  74
  75                 leave:
  76                         HttpAsyncResult result = new HttpAsyncResult (cb,this);
  77                         result.Complete (true, o, null);
  78
  79                         return result;
  80                 }
  81
  82                 void OnEndRequestCache (IAsyncResult result)
  83                 {
  84                 }
  85
  86                 IAsyncResult OnBeginUpdateCache (object o, EventArgs args, AsyncCallback cb, object data)
  87                 {
  88                         HttpApplication app = (HttpApplication) o;
  89                         HttpContext context = app.Context;
  90                         HttpAsyncResult result;
  91
  92                         if (context.Response.IsCached && context.Response.StatusCode == 200 &&
  93                             !context.Trace.IsEnabled)
  94                                 DoCacheInsert (context);
  95
  96                         result = new HttpAsyncResult (cb, this);
  97                         result.Complete (true, o, null);
  98                         return result;
  99                 }
 100
 101                 void OnEndUpdateCache (IAsyncResult result)
 102                 {
 103                 }
 104
 105                 private void DoCacheInsert (HttpContext context)
 106                 {
 107                         string vary_key = context.Request.FilePath;
 108                         string key;
 109                         CachedVaryBy varyby = context.Cache [vary_key] as CachedVaryBy;
 110                         CachedRawResponse prev = null;
 111                         bool lookup = true;
 112
 113                         if (varyby == null) {
 114                                 string path = context.Request.MapPath (vary_key);
 115                                 string [] files = new string [] { path };
 116                                 string [] keys = new string [0];
 117                                 varyby = new CachedVaryBy (context.Response.Cache, vary_key);
 118                                 context.Cache.InsertPrivate (vary_key, varyby,
 119                                                 new CacheDependency (files, keys),
 120                                                 Cache.NoAbsoluteExpiration,
 121                                                 Cache.NoSlidingExpiration,
 122                                                 CacheItemPriority.Normal, null);
 123                                 lookup = false;
 124                         }
 125
 126                         key = varyby.CreateKey (vary_key, context);
 127
 128                         if (lookup)
 129                                 prev = context.Cache [key] as CachedRawResponse;
 130
 131                         if (prev == null) {
 132                                 CachedRawResponse c = context.Response.GetCachedResponse ();
 133                                 string [] files = new string [] { };
 134                                 string [] keys = new string [] { vary_key };
 135                                 bool sliding = context.Response.Cache.Sliding;
 136
 137                                 context.Cache.InsertPrivate (key, c, new CacheDependency (files, keys),
 138                                                 (sliding ? Cache.NoAbsoluteExpiration :
 139                                                                 context.Response.Cache.Expires),
 140                                                 (sliding ? TimeSpan.FromSeconds (
 141                                                         context.Response.Cache.Duration) :
 142                                                                 Cache.NoSlidingExpiration),
 143                                                 CacheItemPriority.Normal, response_removed);
 144                                 c.VaryBy = varyby;
 145                                 varyby.ItemList.Add (key);
 146                         }
 147                 }
 148
 149                 private void OnRawResponseRemoved (string key, object value, CacheItemRemovedReason reason)
 150                 {
 151                         CachedRawResponse c = (CachedRawResponse) value;
 152
 153                         c.VaryBy.ItemList.Remove (key);
 154                         if (c.VaryBy.ItemList.Count != 0)
 155                                 return;
 156
 157                         Cache cache = HttpRuntime.Cache;
 158                         cache.Remove (c.VaryBy.Key);
 159                 }
 160         }
 161 }
 162