Deserialize LinkedCRS with the href from its properties (#102)

* Deserialize LinkedCRS with the href from its properties

Fixes #101

* Added regression test for deserializing LinkedCRS

Author: JoeRobich

src/GeoJSON.Net.Tests/CoordinateReferenceSystem/LinkedCRSTests.cs

@@ -46,6 +46,18 @@ public void Can_Serialize()
             JsonAssert.Contains("{\"properties\":{\"href\":\"http://localhost\"},\"type\":\"link\"}", actualJson);
         }
 
+        [Test]
+        public void Can_Deserialize_CRS_issue_101()
+        {
+            const string pointJson = "{\"type\":\"Point\",\"coordinates\":[2.0,1.0,3.0],\"crs\":{\"properties\":{\"href\":\"http://localhost\"},\"type\":\"link\"}}";
+            var pointWithCRS = JsonConvert.DeserializeObject<Point>(pointJson);
+            var linkCRS = pointWithCRS.CRS as LinkedCRS;
+
+            Assert.IsNotNull(linkCRS);
+            Assert.AreEqual(CRSType.Link, linkCRS.Type);
+            Assert.AreEqual(Href, linkCRS.Properties["href"]);
+        }
+
         [Test]
         public void Ctor_Throws_ArgumentNullExpection_When_Href_String_Is_Null()
         {

src/GeoJSON.Net/Converters/CrsConverter.cs

@@ -77,9 +77,18 @@ public override object ReadJson(JsonReader reader, Type objectType, object exist
             }
             else if (string.Equals("link", crsType, StringComparison.OrdinalIgnoreCase))
             {
-                var linked = new LinkedCRS(string.Empty);
-                serializer.Populate(jObject.CreateReader(), linked);
-                return linked;
+                JObject properties = null;
+                if (jObject.TryGetValue("properties", out token))
+                {
+                    properties = token as JObject;
+                }
+
+                if (properties != null)
+                {
+                    var linked = new LinkedCRS(properties["href"].ToString());
+                    serializer.Populate(jObject.CreateReader(), linked);
+                    return linked;
+                }
             }
 
             return new NotSupportedException(string.Format("Type {0} unexpected.", crsType));
@@ -112,4 +121,4 @@ public override void WriteJson(JsonWriter writer, object value, JsonSerializer s
             }
         }
     }
-}
+}