Forward port of Percolate request sort and response score

Based on PR #1655 for 1.x

Author: russcam

src/Nest/Search/Percolator/MultiPercolate/IPercolateOperation.cs

@@ -16,7 +16,7 @@ public interface IPercolateOperation
 		[JsonProperty(PropertyName = "track_scores")]
 		bool? TrackScores { get; set; }
 
-		[JsonProperty(PropertyName = "score")]
+		[JsonProperty(PropertyName = "sort")]
 		IList<ISort> Sort { get; set; }
 
 		[JsonProperty(PropertyName = "highlight")]

src/Nest/Search/Percolator/Percolate/PercolateRequest.cs

@@ -10,7 +10,6 @@ public partial interface IPercolateRequest<TDocument> : IPercolateOperation
 	{
 		[JsonProperty(PropertyName = "doc")]
 		TDocument Document { get; set; }
-
 	}
 
 	public partial class PercolateRequest<TDocument>
@@ -26,8 +25,26 @@ public PercolateRequest(Id id) : this(typeof(TDocument), typeof(TDocument), id)
 		public AggregationDictionary Aggregations { get; set; }
 
 		public int? Size { get; set; }
+
+		/// <summary>
+		/// Whether the _score is included for each match. The _score is based on the query and represents 
+		/// how the query matched the percolate query’s metadata, not how the document (that is being percolated) 
+		/// matched the query. The <see cref="Query"/> option is required for this option.
+		/// </summary>
 		public bool? TrackScores { get; set; }
+
+		/// <summary>
+		/// The object to percolate
+		/// </summary>
 		public TDocument Document { get; set; }
+
+		/// <summary>
+		/// Define a sort specification like in the search API. Currently only sorting _score reverse 
+		/// (default relevancy) is supported. Other sort fields will throw an exception. 
+		/// The <see cref="Size"/> and <see cref="Query"/> option are required for this setting. Like <see cref="TrackScores"/> 
+		/// the score is based on the query and represents how the query matched to the percolate query’s metadata 
+		/// and not how the document being percolated matched to the query.
+		/// </summary>
 		public IList<ISort> Sort { get; set; }
 
 		IRequestParameters IPercolateOperation.GetRequestParameters() => this.RequestState.RequestParameters;
@@ -63,7 +80,10 @@ public partial class PercolateDescriptor<TDocument> : IPercolateRequest<TDocumen
 		/// </summary>
 		public PercolateDescriptor<TDocument> Document(TDocument @object) => Assign(a => a.Document = @object);
 
-		/// Make sure we keep calculating score even if we are sorting on a field.
+		/// <summary>
+		/// Whether the _score is included for each match. The _score is based on the query and represents 
+		/// how the query matched the percolate query’s metadata, not how the document (that is being percolated) 
+		/// matched the query. The <see cref="Query"/> option is required for this option.
 		/// </summary>
 		public PercolateDescriptor<TDocument> TrackScores(bool? trackScores = true) => Assign(a => a.TrackScores = trackScores);
 
@@ -78,6 +98,13 @@ public PercolateDescriptor<TDocument> Highlight(Func<HighlightDescriptor<TDocume
 
 		public PercolateDescriptor<TDocument> Size(int? size) => Assign(a => a.Size = size);
 
+		/// <summary>
+		/// Define a sort specification like in the search API. Currently only sorting _score reverse 
+		/// (default relevancy) is supported. Other sort fields will throw an exception. 
+		/// The <see cref="Size"/> and <see cref="Query"/> option are required for this setting. Like <see cref="TrackScores"/> 
+		/// the score is based on the query and represents how the query matched to the percolate query’s metadata 
+		/// and not how the document being percolated matched to the query.
+		/// </summary>
 		public PercolateDescriptor<TDocument> Sort(Func<SortDescriptor<TDocument>, IPromise<IList<ISort>>> selector) => Assign(a => a.Sort = selector?.Invoke(new SortDescriptor<TDocument>())?.Value);
 
 		/// <summary>

src/Nest/Search/Percolator/Percolate/PercolateResponse.cs

@@ -18,8 +18,6 @@ public interface IPercolateResponse : IPercolateCountResponse
 	[JsonObject]
 	public class PercolateCountResponse : BaseResponse, IPercolateCountResponse
 	{
-		
-
 		[JsonProperty(PropertyName = "took")]
 		public int Took { get; internal set; }
 
@@ -48,13 +46,17 @@ public class PercolateResponse : PercolateCountResponse, IPercolateResponse
 
 	public class PercolatorMatch
 	{
-		[JsonProperty(PropertyName = "_index")]
-		public string Index { get; set; }
-		[JsonProperty(PropertyName = "_id")]
-		public string Id { get; set; }
 		[JsonProperty(PropertyName = "highlight")]
 		public Dictionary<string, IList<string>> Highlight { get; set; }
-		
+
+		[JsonProperty(PropertyName = "_id")]
+		public string Id { get; set; }
+
+		[JsonProperty(PropertyName = "_index")]
+		public string Index { get; set; }
+
+		[JsonProperty(PropertyName = "_score")]
+		public double Score { get; set; }
 	}
 
 }

src/Tests/Search/Percolator/Percolate/PercolateApiTests.cs

@@ -1,7 +1,9 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using Elasticsearch.Net;
 using FluentAssertions;
+using FluentAssertions.Common;
 using Nest;
 using Tests.Framework;
 using Tests.Framework.Integration;
@@ -46,6 +48,7 @@ protected override void ExpectResponse(IPercolateResponse response)
 			response.Matches.Count().Should().BeGreaterThan(0);
 			var match = response.Matches.First();
 			match.Id.Should().Be(PercolatorId);
+			match.Score.Should().Be(1);
 		}
 
 		private static readonly string PercolatorId = RandomString();
@@ -54,17 +57,28 @@ protected override void OnBeforeCall(IElasticClient client)
 		{
 			var register = this.Client.RegisterPercolator<Project>(PercolatorId, r => r
 				.Index(this.Index)
-				.Query(q => q .MatchAll())
+				.Query(q => q.MatchAll())
 			);
+
+			this.Client.Refresh(this.Index);
 		}
 
 		protected override Func<PercolateDescriptor<Project>, IPercolateRequest<Project>> Fluent => c => c
 			.Index(this.Index)
-			.Document(Project.Instance);
+			.Document(Project.Instance)
+			.Query(q => q.MatchAll())
+			.Size(10)
+			.Sort(s => s.Descending(SortSpecialField.Score))
+			.TrackScores()
+		;
 
 		protected override PercolateRequest<Project> Initializer => new PercolateRequest<Project>(Index, Type<Project>())
 		{
-			Document = Project.Instance
+			Document = Project.Instance,
+			Query = new QueryContainer(new MatchAllQuery()),
+			Size = 10,
+			Sort = new List<ISort> { new SortField { Field = "_score", Order = SortOrder.Descending } },
+			TrackScores = true
 		};
 	}
 
@@ -74,21 +88,21 @@ public class PercolateExistingDocApiTests : ApiTestBase<IPercolateResponse, IPer
 		public PercolateExistingDocApiTests(ReadOnlyCluster cluster, EndpointUsage usage) : base(cluster, usage) { }
 
 		protected override LazyResponses ClientUsage() => Calls(
-			fluent: (c, f) => c.Percolate<Project>(p => p.Id(_percId)),
-			fluentAsync: (c, f) => c.PercolateAsync<Project>(p => p.Id(_percId)),
+			fluent: (c, f) => c.Percolate<Project>(p => p.Id(_percolateId)),
+			fluentAsync: (c, f) => c.PercolateAsync<Project>(p => p.Id(_percolateId)),
 			request: (c, r) => c.Percolate(r),
 			requestAsync: (c, r) => c.PercolateAsync(r)
 		);
 
-		private string _percId = Project.Instance.Name;
+		private readonly string _percolateId = Project.Instance.Name;
 
 		protected override HttpMethod HttpMethod => HttpMethod.POST;
-		protected override string UrlPath => $"project/project/{_percId}/_percolate";
+		protected override string UrlPath => $"project/project/{_percolateId}/_percolate";
 
 		protected override bool SupportsDeserialization => false;
 
 		protected override Func<PercolateDescriptor<Project>, IPercolateRequest<Project>> Fluent => null;
 
-		protected override PercolateRequest<Project> Initializer => new PercolateRequest<Project>(_percId);
+		protected override PercolateRequest<Project> Initializer => new PercolateRequest<Project>(_percolateId);
 	}
 }