mcs/class/System/System.Net/ServicePointManager.cs

   1 //\r
   2 // System.Net.ServicePointManager\r
   3 //\r
   4 // Author:\r
   5 //   Lawrence Pit (loz@cable.a2000.nl)\r
   6 //\r
   7 \r
   8 using System;\r
   9 using System.Collections;\r
  10 using System.Collections.Specialized;\r
  11 using System.Security.Cryptography.X509Certificates;\r
  12 \r
  13 //\r
  14 // notes:\r
  15 // A service point manager manages service points (duh!).\r
  16 // A service point maintains a list of connections (per scheme + authority).\r
  17 // According to HttpWebRequest.ConnectionGroupName each connection group\r
  18 // creates additional connections. therefor, a service point has a hashtable\r
  19 // of connection groups where each value is a list of connections.\r
  20 // \r
  21 // when we need to make an HttpWebRequest, we need to do the following:\r
  22 // 1. find service point, given Uri and Proxy \r
  23 // 2. find connection group, given service point and group name\r
  24 // 3. find free connection in connection group, or create one (if ok due to limits)\r
  25 // 4. lease connection\r
  26 // 5. execute request\r
  27 // 6. when finished, return connection\r
  28 //\r
  29 \r
  30 \r
  31 namespace System.Net \r
  32 {\r
  33         public class ServicePointManager\r
  34         {\r
  35                 private static HybridDictionary servicePoints = new HybridDictionary ();\r
  36                 \r
  37                 // Static properties\r
  38                 \r
  39                 private static ICertificatePolicy policy = null;\r
  40                 private static int defaultConnectionLimit = DefaultPersistentConnectionLimit;\r
  41                 private static int maxServicePointIdleTime = 900000; // 15 minutes\r
  42                 private static int maxServicePoints = 0;\r
  43                 \r
  44                 // Fields\r
  45                 \r
  46                 public const int DefaultNonPersistentConnectionLimit = 4;\r
  47                 public const int DefaultPersistentConnectionLimit = 2;\r
  48                 \r
  49                 // Constructors\r
  50                 private ServicePointManager ()\r
  51                 {\r
  52                 }               \r
  53                 \r
  54                 // Properties\r
  55                 \r
  56                 public static ICertificatePolicy CertificatePolicy {\r
  57                         get { return policy; }\r
  58                         set { policy = value; }\r
  59                 }\r
  60                 \r
  61                 public static int DefaultConnectionLimit {\r
  62                         get { return defaultConnectionLimit; }\r
  63                         set { \r
  64                                 if (value < 0)\r
  65                                         throw new ArgumentOutOfRangeException ("value");\r
  66                                 defaultConnectionLimit = value; \r
  67                         }\r
  68                 }\r
  69                 \r
  70                 public static int MaxServicePointIdleTime {\r
  71                         get { \r
  72                                 return maxServicePointIdleTime;\r
  73                         }\r
  74                         set { \r
  75                                 if (value < -2 || value > Int32.MaxValue)\r
  76                                         throw new ArgumentOutOfRangeException ("value");\r
  77                                 maxServicePointIdleTime = value;\r
  78                         }\r
  79                 }\r
  80                 \r
  81                 public static int MaxServicePoints {\r
  82                         get { \r
  83                                 return maxServicePoints; \r
  84                         }\r
  85                         set {  \r
  86                                 if (value < 0)\r
  87                                         throw new ArgumentException ("value");                          \r
  88                                 maxServicePoints = value;\r
  89                                 RecycleServicePoints ();\r
  90                         }\r
  91                 }\r
  92                 \r
  93                 // Methods\r
  94                 \r
  95                 public static ServicePoint FindServicePoint (Uri address) \r
  96                 {\r
  97                         return FindServicePoint (address, GlobalProxySelection.Select);\r
  98                 }\r
  99                 \r
 100                 public static ServicePoint FindServicePoint (string uriString, IWebProxy proxy)\r
 101                 {\r
 102                         return FindServicePoint (new Uri(uriString), proxy);\r
 103                 }\r
 104                 \r
 105                 public static ServicePoint FindServicePoint (Uri address, IWebProxy proxy)\r
 106                 {\r
 107                         RecycleServicePoints ();\r
 108                         \r
 109                         if (address == null)\r
 110                                 throw new ArgumentNullException ("address");\r
 111 \r
 112                         if (proxy != null && !proxy.IsBypassed(address)) {\r
 113                                 address = proxy.GetProxy (address);                             \r
 114                         } \r
 115 \r
 116                         address = new Uri (address.Scheme + "://" + address.Authority);\r
 117                         \r
 118                         ServicePoint sp = null;\r
 119                         lock (servicePoints) {\r
 120                                 sp = (ServicePoint) servicePoints [address];\r
 121                                 if (sp != null)\r
 122                                         return sp;\r
 123                                 if (maxServicePoints > 0 && servicePoints.Count >= maxServicePoints)\r
 124                                         throw new InvalidOperationException ("maximum number of service points reached");\r
 125                                 sp = new ServicePoint (address, defaultConnectionLimit, maxServicePointIdleTime);\r
 126                                 servicePoints.Add (address, sp);\r
 127                         }\r
 128                         \r
 129                         return sp;\r
 130                 }\r
 131                 \r
 132                 // Internal Methods\r
 133 \r
 134                 internal static void RecycleServicePoints ()\r
 135                 {\r
 136                         ArrayList toRemove = new ArrayList ();\r
 137                         lock (servicePoints) {\r
 138                                 IDictionaryEnumerator e = servicePoints.GetEnumerator ();\r
 139                                 while (e.MoveNext ()) {\r
 140                                         ServicePoint sp = (ServicePoint) e.Value;\r
 141                                         if (sp.AvailableForRecycling) {\r
 142                                                 toRemove.Add (e.Key);\r
 143                                         }\r
 144                                 }\r
 145                                 \r
 146                                 for (int i = 0; i < toRemove.Count; i++) \r
 147                                         servicePoints.Remove (toRemove [i]);\r
 148 \r
 149                                 if (maxServicePoints == 0 || servicePoints.Count <= maxServicePoints)\r
 150                                         return;\r
 151 \r
 152                                 // get rid of the ones with the longest idle time\r
 153                                 SortedList list = new SortedList (servicePoints.Count);\r
 154                                 e = servicePoints.GetEnumerator ();\r
 155                                 while (e.MoveNext ()) {\r
 156                                         ServicePoint sp = (ServicePoint) e.Value;\r
 157                                         if (sp.CurrentConnections == 0) {\r
 158                                                 while (list.ContainsKey (sp.IdleSince))\r
 159                                                         sp.IdleSince.AddMilliseconds (1);\r
 160                                                 list.Add (sp.IdleSince, sp.Address);\r
 161                                         }\r
 162                                 }\r
 163                                 \r
 164                                 for (int i = 0; i < list.Count && servicePoints.Count > maxServicePoints; i++)\r
 165                                         servicePoints.Remove (list.GetByIndex (i));\r
 166                         }\r
 167                 }\r
 168         }\r
 169 }