added title, and ability for any metadatafield to be specified on the attachment mapping fixes #330

Author: Mpdreamz

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

@@ -1,4 +1,4 @@
-  {
+{
   "elasticsearchprojects": {
     "properties": {
       "myAttachment": {
@@ -9,6 +9,16 @@
             "store": "yes",
             "index": "not_analyzed"
           },
+          "title": {
+            "type": "string",
+            "store": "no",
+            "index": "not_analyzed"
+          },
+          "contents": {
+            "type": "string",
+            "store": "no",
+            "index": "not_analyzed"
+          },
           "author": {
             "type": "string",
             "store": "no",

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

@@ -115,6 +115,8 @@ public void AttachmentProperty()
 					.Attachment(s => s
 						.Name(p => p.MyAttachment)
 						.FileField(fs => fs.Index(FieldIndexOption.not_analyzed).Store())
+						.TitleField(fs => fs.Index(FieldIndexOption.not_analyzed).Store(false))
+						.MetadataField("contents", fs => fs.Index(FieldIndexOption.not_analyzed).Store(false))
 						.AuthorField(fs => fs.Index(FieldIndexOption.analyzed).Store(false))
 						.DateField(fs => fs.Store(false).IncludeInAll())
 					)

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

@@ -34,11 +34,30 @@ public AttachmentMappingDescriptor<T> AuthorField(Func<StringMappingDescriptor<T
 		{
 			stringMapper.ThrowIfNull("stringMapper");
 			var d = stringMapper(new StringMappingDescriptor<T>());
-			d.ThrowIfNull("stringMapper return value");
+			d.ThrowIfNull("attachment author field mapping");
 
 			this._Mapping.Fields["author"] = d._Mapping;
 			return this;
 		}
+		public AttachmentMappingDescriptor<T> TitleField(Func<StringMappingDescriptor<T>, StringMappingDescriptor<T>> stringMapper)
+		{
+			stringMapper.ThrowIfNull("stringMapper");
+			var d = stringMapper(new StringMappingDescriptor<T>());
+			d.ThrowIfNull("attachment title field");
+
+			this._Mapping.Fields["title"] = d._Mapping;
+			return this;
+		}
+		public AttachmentMappingDescriptor<T> MetadataField(string metadataFieldName, Func<StringMappingDescriptor<T>, StringMappingDescriptor<T>> stringMapper)
+		{
+			metadataFieldName.ThrowIfNullOrEmpty("metadataFieldName");
+			stringMapper.ThrowIfNull("stringMapper");
+			var d = stringMapper(new StringMappingDescriptor<T>());
+			d.ThrowIfNull("attachment metadata field");
+
+			this._Mapping.Fields[metadataFieldName] = d._Mapping;
+			return this;
+		}
 		public AttachmentMappingDescriptor<T> DateField(Func<DateMappingDescriptor<T>, DateMappingDescriptor<T>> dateMapper)
 		{
 			dateMapper.ThrowIfNull("stringMapper");