more meaningful external_lot_ids conversion

closes #3

BrickOwlSharp.Client/Inventory.cs

@@ -96,7 +96,7 @@ public class Inventory
         [JsonPropertyName("ids")]
         public List<Reference> Ids { get; set; } = new List<Reference>(); 
 
-        [JsonPropertyName("external_lot_ids")]
+        [JsonPropertyName("external_lot_ids"), JsonConverter(typeof(ExternalLotIdConverter))]
         public List<Reference> ExternalLotIds { get; set; } = new List<Reference>();
     }
 }

BrickOwlSharp.Client/Json/ExternalLotIdConverter.cs

@@ -0,0 +1,69 @@
+#region License
+// Copyright (c) 2020 Jens Eisenbach
+//
+// Permission is hereby granted, free of charge, to any person
+// obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without
+// restriction, including without limitation the rights to use,
+// copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following
+// conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+using BrickOwlSharp;
+
+namespace BrickOwlSharp.Client.Json
+{
+    internal class ExternalLotIdConverter : JsonConverter<List<Reference>>
+    {
+        public override List<Reference> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            List<Reference> references = new List<Reference>();
+
+            if (reader.TokenType == JsonTokenType.StartArray)
+            {
+                // the array is only used when the external_lot_ids property is empty
+                reader.Read();
+            }
+            else if (reader.TokenType == JsonTokenType.StartObject)
+            {
+                JsonNode node = JsonObject.Parse(ref reader);
+
+                if (node["other"] != null)
+                {
+                    references.Add(new Reference()
+                    {
+                        Type = IdType.Other,
+                        Id = node["other"].ToString()
+                    });
+                }
+            }
+
+            return references;
+        } // !Read()
+
+
+        public override void Write(Utf8JsonWriter writer, List<Reference> value, JsonSerializerOptions options)
+        {            
+            writer.WriteStringValue(""); // ???
+        } // !Write()
+    }
+}