An OpenApi (swagger) parser to generate MappingModel or mapping.json file (#479)

* wip

* .

* .

* nuget

* .

* .

* WithMappingModel

* tests

* json

* codefactor

* sign

* .

* interface

* sln

* comments

src/WireMock.Net.OpenApiParser/Extensions/WireMockServerExtensions.cs

@@ -0,0 +1,59 @@
+using System;
+using System.IO;
+using System.Linq;
+using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.Readers;
+using WireMock.Server;
+
+namespace WireMock.Net.OpenApiParser.Extensions
+{
+    public static class WireMockServerExtensions
+    {
+        /// <summary>
+        /// Register the mappings via an OpenAPI (swagger) V2 or V3 file.
+        /// </summary>
+        /// <param name="server">The WireMockServer instance</param>
+        /// <param name="path">Path containing OpenAPI file to parse and use the mappings.</param>
+        /// <param name="diagnostic">Returns diagnostic object containing errors detected during parsing</param>
+        public static IWireMockServer WithMappingFromOpenApiFile(this IWireMockServer server, string path, out OpenApiDiagnostic diagnostic)
+        {
+            if (server == null)
+            {
+                throw new ArgumentNullException(nameof(server));
+            }
+            if (string.IsNullOrEmpty(path))
+            {
+                throw new ArgumentNullException(nameof(path));
+            }
+
+            var mappings = new WireMockOpenApiParser().FromFile(path, out diagnostic);
+
+            return server.WithMapping(mappings.ToArray());
+        }
+
+        /// <summary>
+        /// Register the mappings via an OpenAPI (swagger) V2 or V3 stream.
+        /// </summary>
+        /// <param name="server">The WireMockServer instance</param>
+        /// <param name="stream">Stream containing OpenAPI description to parse and use the mappings.</param>
+        /// <param name="diagnostic">Returns diagnostic object containing errors detected during parsing</param>
+        public static IWireMockServer WithMappingFromOpenApiStream(this IWireMockServer server, Stream stream, out OpenApiDiagnostic diagnostic)
+        {
+            var mappings = new WireMockOpenApiParser().FromStream(stream, out diagnostic);
+
+            return server.WithMapping(mappings.ToArray());
+        }
+
+        /// <summary>
+        /// Register the mappings via an OpenAPI (swagger) V2 or V3 document.
+        /// </summary>
+        /// <param name="server">The WireMockServer instance</param>
+        /// <param name="document">The OpenAPI document to use as mappings.</param>
+        public static IWireMockServer WithMappingFromOpenApiDocument(this IWireMockServer server, OpenApiDocument document)
+        {
+            var mappings = new WireMockOpenApiParser().FromDocument(document);
+
+            return server.WithMapping(mappings.ToArray());
+        }
+    }
+}