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         class DummyPolicy : ICertificatePolicy\r
  34         {\r
  35                 public bool CheckValidationResult (ServicePoint point,\r
  36                                                    X509Certificate certificate,\r
  37                                                    WebRequest request,\r
  38                                                    int certificateProblem)\r
  39                 {\r
  40                         return (certificateProblem == 0);\r
  41                 }\r
  42         }\r
  43         \r
  44         public class ServicePointManager\r
  45         {\r
  46                 private static HybridDictionary servicePoints = new HybridDictionary ();\r
  47                 \r
  48                 // Static properties\r
  49                 \r
  50                 private static ICertificatePolicy policy = new DummyPolicy ();\r
  51                 private static int defaultConnectionLimit = DefaultPersistentConnectionLimit;\r
  52                 private static int maxServicePointIdleTime = 900000; // 15 minutes\r
  53                 private static int maxServicePoints = 0;\r
  54                 \r
  55                 // Fields\r
  56                 \r
  57                 public const int DefaultNonPersistentConnectionLimit = 4;\r
  58                 public const int DefaultPersistentConnectionLimit = 2;\r
  59                 \r
  60                 // Constructors\r
  61                 private ServicePointManager ()\r
  62                 {\r
  63                 }               \r
  64                 \r
  65                 // Properties\r
  66                 \r
  67                 public static ICertificatePolicy CertificatePolicy {\r
  68                         get { return policy; }\r
  69                         set { policy = value; }\r
  70                 }\r
  71                 \r
  72                 public static int DefaultConnectionLimit {\r
  73                         get { return defaultConnectionLimit; }\r
  74                         set { \r
  75                                 if (value <= 0)\r
  76                                         throw new ArgumentOutOfRangeException ("value");\r
  77 \r
  78                                 defaultConnectionLimit = value; \r
  79                         }\r
  80                 }\r
  81                 \r
  82                 public static int MaxServicePointIdleTime {\r
  83                         get { \r
  84                                 return maxServicePointIdleTime;\r
  85                         }\r
  86                         set { \r
  87                                 if (value < -2 || value > Int32.MaxValue)\r
  88                                         throw new ArgumentOutOfRangeException ("value");\r
  89                                 maxServicePointIdleTime = value;\r
  90                         }\r
  91                 }\r
  92                 \r
  93                 public static int MaxServicePoints {\r
  94                         get { \r
  95                                 return maxServicePoints; \r
  96                         }\r
  97                         set {  \r
  98                                 if (value < 0)\r
  99                                         throw new ArgumentException ("value");                          \r
 100 \r
 101                                 maxServicePoints = value;\r
 102                                 RecycleServicePoints ();\r
 103                         }\r
 104                 }\r
 105                 \r
 106                 // Methods\r
 107                 \r
 108                 public static ServicePoint FindServicePoint (Uri address) \r
 109                 {\r
 110                         return FindServicePoint (address, GlobalProxySelection.Select);\r
 111                 }\r
 112                 \r
 113                 public static ServicePoint FindServicePoint (string uriString, IWebProxy proxy)\r
 114                 {\r
 115                         return FindServicePoint (new Uri(uriString), proxy);\r
 116                 }\r
 117                 \r
 118                 public static ServicePoint FindServicePoint (Uri address, IWebProxy proxy)\r
 119                 {\r
 120                         if (address == null)\r
 121                                 throw new ArgumentNullException ("address");\r
 122 \r
 123                         RecycleServicePoints ();\r
 124                         \r
 125                         if (proxy != null && !proxy.IsBypassed(address)) {\r
 126                                 address = proxy.GetProxy (address);\r
 127                                 if (address.Scheme != "http" && address.Scheme != "https")\r
 128                                         throw new NotSupportedException ("Proxy scheme not supported.");\r
 129                         } \r
 130 \r
 131                         address = new Uri (address.Scheme + "://" + address.Authority);\r
 132                         \r
 133                         ServicePoint sp = null;\r
 134                         lock (servicePoints) {\r
 135                                 sp = servicePoints [address] as ServicePoint;\r
 136                                 if (sp != null)\r
 137                                         return sp;\r
 138 \r
 139                                 if (maxServicePoints > 0 && servicePoints.Count >= maxServicePoints)\r
 140                                         throw new InvalidOperationException ("maximum number of service points reached");\r
 141                                 sp = new ServicePoint (address, defaultConnectionLimit, maxServicePointIdleTime);\r
 142                                 servicePoints.Add (address, sp);\r
 143                         }\r
 144                         \r
 145                         return sp;\r
 146                 }\r
 147                 \r
 148                 // Internal Methods\r
 149 \r
 150                 internal static void RecycleServicePoints ()\r
 151                 {\r
 152                         ArrayList toRemove = new ArrayList ();\r
 153                         lock (servicePoints) {\r
 154                                 IDictionaryEnumerator e = servicePoints.GetEnumerator ();\r
 155                                 while (e.MoveNext ()) {\r
 156                                         ServicePoint sp = (ServicePoint) e.Value;\r
 157                                         if (sp.AvailableForRecycling) {\r
 158                                                 toRemove.Add (e.Key);\r
 159                                         }\r
 160                                 }\r
 161                                 \r
 162                                 for (int i = 0; i < toRemove.Count; i++) \r
 163                                         servicePoints.Remove (toRemove [i]);\r
 164 \r
 165                                 if (maxServicePoints == 0 || servicePoints.Count <= maxServicePoints)\r
 166                                         return;\r
 167 \r
 168                                 // get rid of the ones with the longest idle time\r
 169                                 SortedList list = new SortedList (servicePoints.Count);\r
 170                                 e = servicePoints.GetEnumerator ();\r
 171                                 while (e.MoveNext ()) {\r
 172                                         ServicePoint sp = (ServicePoint) e.Value;\r
 173                                         if (sp.CurrentConnections == 0) {\r
 174                                                 while (list.ContainsKey (sp.IdleSince))\r
 175                                                         sp.IdleSince.AddMilliseconds (1);\r
 176                                                 list.Add (sp.IdleSince, sp.Address);\r
 177                                         }\r
 178                                 }\r
 179                                 \r
 180                                 for (int i = 0; i < list.Count && servicePoints.Count > maxServicePoints; i++)\r
 181                                         servicePoints.Remove (list.GetByIndex (i));\r
 182                         }\r
 183                 }\r
 184         }\r
 185 }\r