Create Json schema mappings with references in components

Author: MaggieKimani1

src/Microsoft.OpenApi.Readers/ParseNodes/MapNode.cs

@@ -8,6 +8,7 @@
 using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Nodes;
+using Json.Schema;
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Interfaces;
 using Microsoft.OpenApi.Models;
@@ -123,6 +124,63 @@ public override Dictionary<string, T> CreateMapWithReference<T>(
             return nodes.Where(n => n != default).ToDictionary(k => k.key, v => v.value);
         }
 
+        public override Dictionary<string, JsonSchema> CreateJsonSchemaMapWithReference(
+            ReferenceType referenceType,
+            Func<MapNode, JsonSchema> map,
+            OpenApiSpecVersion version)
+        {
+            var jsonMap = _node ?? throw new OpenApiReaderException($"Expected map while parsing {typeof(JsonSchema).Name}", Context);
+
+            var nodes = jsonMap.Select(
+                n =>
+                {
+                    var key = n.Key;
+                    (string key, JsonSchema value) entry;
+                    try
+                    {
+                        Context.StartObject(key);
+                        entry = (key,
+                            value: map(new MapNode(Context, (JsonObject)n.Value))
+                        );
+                        if (entry.value == null)
+                        {
+                            return default;  // Body Parameters shouldn't be converted to Parameters
+                        }
+                        // If the component isn't a reference to another component, then point it to itself.
+                        if (entry.value.GetRef() == null)
+                        {
+                            var builder = new JsonSchemaBuilder();
+
+                            // construct the Ref and append it to the builder
+                            var reference = version == OpenApiSpecVersion.OpenApi2_0 ? string.Concat("#/definitions/", entry.key) :
+                                string.Concat("#/components/schemas/", entry.key);
+
+                            builder.Ref(reference);
+
+                            // Append all the keywords in original schema to our new schema using a builder instance
+                            foreach (var keyword in entry.value.Keywords)
+                            {
+                                builder.Add(keyword);
+                            }
+                            entry.value = builder.Build();
+                            //entry.value.GetRef() = new OpenApiReference()
+                            //{
+                            //    Type = referenceType,
+                            //    Id = entry.key
+                            //};
+
+                        }
+                    }
+                    finally
+                    {
+                        Context.EndObject();
+                    }
+                    return entry;
+                }
+                );
+            return nodes.Where(n => n != default).ToDictionary(k => k.key, v => v.value);
+        }
+
         public override Dictionary<string, T> CreateSimpleMap<T>(Func<ValueNode, T> map)
         {
             var jsonMap = _node ?? throw new OpenApiReaderException($"Expected map while parsing {typeof(T).Name}", Context);

src/Microsoft.OpenApi.Readers/ParseNodes/ParseNode.cs

@@ -1,9 +1,10 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
 using System;
 using System.Collections.Generic;
 using System.Text.Json.Nodes;
+using Json.Schema;
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Interfaces;
 using Microsoft.OpenApi.Models;
@@ -66,6 +67,14 @@ public virtual Dictionary<string, T> CreateMapWithReference<T>(
             throw new OpenApiReaderException("Cannot create map from this reference.", Context);
         }
 
+        public virtual Dictionary<string, JsonSchema> CreateJsonSchemaMapWithReference(
+            ReferenceType referenceType,
+            Func<MapNode, JsonSchema> map,
+            OpenApiSpecVersion version)
+        {
+            throw new OpenApiReaderException("Cannot create map from this reference.", Context);
+        }
+
         public virtual List<T> CreateSimpleList<T>(Func<ValueNode, T> map)
         {
             throw new OpenApiReaderException("Cannot create simple list from this type of node.", Context);

src/Microsoft.OpenApi.Readers/V2/OpenApiDocumentDeserializer.cs

@@ -64,8 +64,7 @@ internal static partial class OpenApiV2Deserializer
                         o.Components = new();
                     }
 
-                    o.Components.Schemas = n.CreateMap(LoadSchema);
-                }
+                o.Components.Schemas = n.CreateJsonSchemaMapWithReference(ReferenceType.Schema, LoadSchema, OpenApiSpecVersion.OpenApi2_0);                }
             },
             {
                 "parameters",

src/Microsoft.OpenApi.Readers/V3/OpenApiComponentsDeserializer.cs

@@ -20,7 +20,7 @@ internal static partial class OpenApiV3Deserializer
     {
         private static readonly FixedFieldMap<OpenApiComponents> _componentsFixedFields = new()
         {
-            {"schemas", (o, n) => o.Schemas = n.CreateMap(LoadSchema)},
+            {"schemas", (o, n) => o.Schemas =  n.CreateJsonSchemaMapWithReference(ReferenceType.Schema, LoadSchema, OpenApiSpecVersion.OpenApi3_0)},
             {"responses", (o, n) => o.Responses = n.CreateMapWithReference(ReferenceType.Response, LoadResponse)},
             {"parameters", (o, n) => o.Parameters = n.CreateMapWithReference(ReferenceType.Parameter, LoadParameter)},
             {"examples", (o, n) => o.Examples = n.CreateMapWithReference(ReferenceType.Example, LoadExample)},