Optional params

Kveer.XmlRPC.Tests/paramstest.cs

@@ -64,8 +64,14 @@
 			return args;
 		}
 
+        [XmlRpcMethod]
+        public int OptioanlNullParameter(string optional = null)
+        {
+            return 1;
+        }
 
-		private readonly string massimoRequest =
+
+        private readonly string massimoRequest =
 			@"<?xml version=""1.0""?>
 <methodCall>
   <methodName>Send_Param</methodName>
@@ -579,7 +585,49 @@
 					.Replace("\r\n", Environment.NewLine), reqstr);
 		}
 
-		[Test]
+        [Test]
+        public void SerializeNullParameterUnallowed()
+        {
+            Assert.Throws<XmlRpcNullParameterException>(
+                    () => SerializeNullParameter(XmlRpcNonStandard.None));
+        }
+
+        [Test]
+        public void SerializeNullParameter()
+        {
+            string reqstr = SerializeNullParameter(XmlRpcNonStandard.AllowNull);
+            Assert.AreEqual(
+                @"<?xml version=""1.0""?>
+<methodCall>
+  <methodName>SerializeOptionalNullParameter</methodName>
+  <params>
+    <param>
+      <value>
+        <nil />
+      </value>
+    </param>
+  </params>
+</methodCall>"
+                    .Replace("\r\n", Environment.NewLine), reqstr);
+        }
+
+        private string SerializeNullParameter(XmlRpcNonStandard options)
+        {
+            Stream stm = new MemoryStream();
+            var req = new XmlRpcRequest();
+            req.args = new object[] { null };
+            req.method = "SerializeOptionalNullParameter";
+            req.mi = typeof(IFoo).GetMethod("SerializeOptionalNullParameter");
+            var ser = new XmlRpcSerializer();
+            ser.NonStandard = options;
+            ser.SerializeRequest(stm, req);
+            stm.Position = 0;
+            TextReader tr = new StreamReader(stm);
+            var reqstr = tr.ReadToEnd();
+            return reqstr;
+        }        
+
+        [Test]
 		public void SerializeZeroParameters()
 		{
 			Stream stm = new MemoryStream();

Kveer.XmlRPC/XmlRpcNonStandard.cs

@@ -37,6 +37,7 @@ public enum XmlRpcNonStandard
 		MapZerosDateTimeToMinValue = 0x8,
 		MapEmptyDateTimeToMinValue = 0x10,
 		AllowInvalidHttpContent    = 0x20,
-		All                        = 0x7fff
+        AllowNull                  = 0x40,
+        All                        = 0x7fff
 	}
 }

Kveer.XmlRPC/XmlRpcSerializer.cs

@@ -72,7 +72,9 @@ public class XmlRpcSerializer
 
 		private bool MapZerosDateTimeToMinValue => (NonStandard & XmlRpcNonStandard.MapZerosDateTimeToMinValue) != 0;
 
-		public void SerializeRequest(Stream stm, XmlRpcRequest request)
+        private bool AllowNull => (NonStandard & XmlRpcNonStandard.AllowNull) != 0;
+
+        public void SerializeRequest(Stream stm, XmlRpcRequest request)
 		{
 			var xtw = new XmlTextWriter(stm, XmlEncoding);
 			ConfigureXmlFormat(xtw);
@@ -137,11 +139,24 @@ private void SerializeParams(XmlTextWriter xtw, XmlRpcRequest request,
 					}
 				}
 
-				if (request.args[i] == null)
-					throw new XmlRpcNullParameterException(string.Format(
-															   "Null method parameter #{0}", i + 1));
-				xtw.WriteStartElement("", "param", "");
-				Serialize(xtw, request.args[i], mappingAction);
+                xtw.WriteStartElement("", "param", "");
+                if (request.args[i] == null)
+                {
+                    if (!AllowNull)
+                    {
+                        throw new XmlRpcNullParameterException(string.Format(
+                                                               "Null method parameter #{0}", i + 1));
+                    }
+
+                    xtw.WriteStartElement("", "value", "");
+                    xtw.WriteStartElement("", "nil", "");
+                    xtw.WriteEndElement();
+                    xtw.WriteEndElement();
+                }
+                else
+                {   
+                    Serialize(xtw, request.args[i], mappingAction);
+                }
 				xtw.WriteEndElement();
 			}
 		}