Merge pull request #646 from rajeshsubhankar/feature/NRediSearch-Sorting

Feature- NRediSearch Sorting Functionality

NRediSearch/Query.cs

@@ -161,6 +161,16 @@ public Paging(int offset, int count)
         /// </summary>
         public byte[] Payload { get; set; }
 
+        /// <summary>
+        /// Set the query parameter to sort by
+        /// </summary>
+        public string SortBy { get; set; }
+
+        /// <summary>
+        /// Set the query parameter to sort by ASC by default
+        /// </summary>
+        public bool SortAscending {get; set;} = true;
+
         /// <summary>
         /// Create a new index
         /// </summary>
@@ -205,6 +215,13 @@ internal void SerializeRedisArgs(List<object> args)
                 args.AddRange(_fields);
             }
 
+            if(SortBy != null)
+            {
+                args.Add("SORTBY".Literal());
+                args.Add(SortBy);
+                args.Add((SortAscending ? "ASC" : "DESC").Literal());
+            }
+
             if (Payload != null)
             {
                 args.Add("PAYLOAD".Literal());
@@ -260,5 +277,18 @@ public Query LimitFields(params string[] fields)
             this._fields = fields;
             return this;
         }
+
+        /// <summary>
+        /// Set the query to be sorted by a sortable field defined in the schema
+        /// </summary>
+        /// <param name="field">the sorting field's name</param>
+        /// <param name="ascending">if set to true, the sorting order is ascending, else descending</param>
+        /// <returns>the query object itself</returns>
+        public Query SetSortBy(string field, bool ascending = true)
+        {
+            SortBy = field;
+            SortAscending = ascending;
+            return this;
+        }
     }
 }

NRediSearch/Schema.cs

@@ -22,11 +22,13 @@ public class Field
         {
             public String Name { get; }
             public FieldType Type { get; }
+            public bool Sortable {get;}
 
-            internal Field(string name, FieldType type)
+            internal Field(string name, FieldType type, bool sortable)
             {
                 Name = name;
                 Type = type;
+                Sortable = sortable;
             }
 
             internal virtual void SerializeRedisArgs(List<object> args)
@@ -43,12 +45,17 @@ object GetForRedis(FieldType type)
                 }
                 args.Add(Name);
                 args.Add(GetForRedis(Type));
+                if(Sortable){args.Add("SORTABLE");}
             }
         }
         public class TextField : Field
         {
             public double Weight { get; }
-            internal TextField(string name, double weight = 1.0) : base(name, FieldType.FullText)
+            internal TextField(string name, double weight = 1.0) : base(name, FieldType.FullText, false)
+            {
+                Weight = weight;
+            }
+            internal TextField(string name, bool sortable, double weight = 1.0) : base(name, FieldType.FullText, sortable)
             {
                 Weight = weight;
             }
@@ -77,6 +84,18 @@ public Schema AddTextField(string name, double weight = 1.0)
             return this;
         }
 
+        /// <summary>
+        /// Add a text field that can be sorted on
+        /// </summary>
+        /// <param name="name">the field's name</param>
+        /// <param name="weight">its weight, a positive floating point number</param>
+        /// <returns>the schema object</returns>
+        public Schema AddSortableTextField(string name, double weight = 1.0)
+        {
+            Fields.Add(new TextField(name, true, weight));
+            return this;
+        }
+
         /// <summary>
         /// Add a numeric field to the schema
         /// </summary>
@@ -84,7 +103,7 @@ public Schema AddTextField(string name, double weight = 1.0)
         /// <returns>the schema object</returns>
         public Schema AddGeoField(string name)
         {
-            Fields.Add(new Field(name, FieldType.Geo));
+            Fields.Add(new Field(name, FieldType.Geo, false));
             return this;
         }
 
@@ -95,7 +114,18 @@ public Schema AddGeoField(string name)
         /// <returns>the schema object</returns>
         public Schema AddNumericField(string name)
         {
-            Fields.Add(new Field(name, FieldType.Numeric));
+            Fields.Add(new Field(name, FieldType.Numeric, false));
+            return this;
+        }
+
+        /// <summary>
+        /// Add a numeric field that can be sorted on
+        /// </summary>
+        /// <param name="name">the field's name</param>
+        /// <returns>the schema object</returns>
+        public Schema AddSortableNumericField(string name)
+        {
+            Fields.Add(new Field(name, FieldType.Numeric, true));
             return this;
         }