added copy to field mapping support for appropriate types

Author: gmarz

Diff for: src/Nest/Domain/Mapping/Descriptors/BinaryMappingDescriptor.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using System.Linq.Expressions;
 using Nest.Resolvers;
 
@@ -25,5 +26,16 @@ public BinaryMappingDescriptor<T> IndexName(string indexName)
 			return this;
 		}
 
+		public BinaryMappingDescriptor<T> CopyTo(params string[] fields)
+		{
+			this._Mapping.CopyTo = fields.Select(f => (PropertyPathMarker)f);
+			return this;
+		}
+
+		public BinaryMappingDescriptor<T> CopyTo(params Expression<Func<T, object>>[] objectPaths)
+		{
+			this._Mapping.CopyTo = objectPaths.Select(e => (PropertyPathMarker)e);
+			return this;
+		}
 	}
 }

Diff for: src/Nest/Domain/Mapping/Descriptors/BooleanMappingDescriptor.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using System.Linq.Expressions;
 using Nest.Resolvers;
 
@@ -52,6 +53,16 @@ public BooleanMappingDescriptor<T> IncludeInAll(bool includeInAll = true)
 			return this;
 		}
 
+		public BooleanMappingDescriptor<T> CopyTo(params string[] fields)
+		{
+			this._Mapping.CopyTo = fields.Select(f => (PropertyPathMarker)f);
+			return this;
+		}
 
+		public BooleanMappingDescriptor<T> CopyTo(params Expression<Func<T, object>>[] objectPaths)
+		{
+			this._Mapping.CopyTo = objectPaths.Select(e => (PropertyPathMarker)e);
+			return this;
+		}
 	}
 }

Diff for: src/Nest/Domain/Mapping/Descriptors/StringMappingDescriptor.cs

@@ -1,4 +1,5 @@
-using System;
+using System;
+using System.Linq;
 using System.Linq.Expressions;
 using Nest.Resolvers;
 
@@ -92,5 +93,16 @@ public StringMappingDescriptor<T> PositionOffsetGap(int positionOffsetGap)
 			return this;
 		}
 
+		public StringMappingDescriptor<T> CopyTo(params string[] fields)
+		{
+			this._Mapping.CopyTo = fields.Select(f => (PropertyPathMarker)f);
+			return this;
+		}
+
+		public StringMappingDescriptor<T> CopyTo(params Expression<Func<T, object>>[] objectPaths)
+		{
+			this._Mapping.CopyTo = objectPaths.Select(e => (PropertyPathMarker)e);
+			return this;
+		}
 	}
 }

Diff for: src/Nest/Domain/Mapping/Types/BinaryMapping.cs

@@ -24,5 +24,8 @@ public class BinaryMapping : IElasticType, IElasticCoreType
 		/// </summary>
 		[JsonProperty("index_name")]
 		public string IndexName { get; set; }
+
+		[JsonProperty("copy_to")]
+		public IEnumerable<PropertyPathMarker> CopyTo { get; set; }
 	}
 }

Diff for: src/Nest/Domain/Mapping/Types/BooleanMapping.cs

@@ -40,5 +40,7 @@ public class BooleanMapping : IElasticType, IElasticCoreType
 		[JsonProperty("include_in_all")]
 		public bool? IncludeInAll { get; set; }
 
+		[JsonProperty("copy_to")]
+		public IEnumerable<PropertyPathMarker> CopyTo { get; set; }
 	}
 }

Diff for: src/Nest/Domain/Mapping/Types/StringMapping.cs

@@ -62,7 +62,9 @@ public class StringMapping : IElasticType, IElasticCoreType
 		public bool? IncludeInAll { get; set; }
 
 		[JsonProperty("position_offset_gap")]
-		public int? PositionOffsetGap { get; set; }
-
+		public int? PositionOffsetGap { get; set; }
+
+		[JsonProperty("copy_to")]
+		public IEnumerable<PropertyPathMarker> CopyTo { get; set; }
 	}
 }

Diff for: src/Tests/Nest.Tests.Unit/Core/Map/FluentMappingFullExampleTests.cs

@@ -138,6 +138,7 @@ public void MapFluentFull()
 						.Store()
 						.TermVector(TermVectorOption.with_positions_offsets)
 						.Boost(1.1)
+						.CopyTo(p => p.Content)
 					)
 					.Number(s => s
 						.Name(p => p.LOC)

Diff for: src/Tests/Nest.Tests.Unit/Core/Map/Properties/BinaryProperty.json

@@ -3,7 +3,8 @@
     "properties": {
       "myBinaryField": {
         "type": "binary",
-        "index_name": "binz"
+        "index_name": "binz",
+		"copy_to":  ["another_field"]
       }
     }
   }

Diff for: src/Tests/Nest.Tests.Unit/Core/Map/Properties/BooleanProperty.json

@@ -8,7 +8,8 @@
         "index": "analyzed",
         "boost": 1.4,
         "null_value": false,
-        "include_in_all": true
+        "include_in_all": true,
+		"copy_to":  ["content"]
       }
     }
   }

Diff for: src/Tests/Nest.Tests.Unit/Core/Map/Properties/PropertiesTests.cs

@@ -28,6 +28,7 @@ public void StringProperty()
 						.Store()
 						.TermVector(TermVectorOption.with_positions_offsets)
 						.Boost(1.1)
+						.CopyTo(p => p.Content, p => p.Country)
 					)
 				)
 			);
@@ -88,6 +89,7 @@ public void BooleanProperty()
 						.IndexName("bool_name_in_lucene_index")
 						.NullValue(false)
 						.Store()
+						.CopyTo(p => p.Content)
 					)
 				)
 			);
@@ -101,6 +103,7 @@ public void BinaryProperty()
 					.Binary(s => s
 						.Name(p => p.MyBinaryField)
 						.IndexName("binz")
+						.CopyTo("another_field")
 					)
 				)
 			);

Diff for: src/Tests/Nest.Tests.Unit/Core/Map/Properties/StringProperty.json

@@ -14,7 +14,8 @@
         "index_analyzer": "standard",
         "search_analyzer": "standard",
         "include_in_all": true,
-        "position_offset_gap": 1
+        "position_offset_gap": 1,
+		"copy_to" :  ["content", "country"]
       }
     }
   }