add the write functionality for each open api element

src/Microsoft.OpenApi.Readers/YamlReaders/OpenApiV2Deserializer.cs

@@ -83,7 +83,7 @@ public static OpenApiDocument LoadOpenApi(RootNode rootNode)
         {
             { "title",      (o,n) => { o.Title = n.GetScalarValue(); } },
             { "description", (o,n) => { o.Description = n.GetScalarValue(); } },
-            { "termsOfService", (o,n) => { o.TermsOfService = n.GetScalarValue(); } },
+            { "termsOfService", (o,n) => { o.TermsOfService = new Uri(n.GetScalarValue()); } },
             { "contact",    (o,n) => { o.Contact = LoadContact(n); } },
             { "license",    (o,n) => { o.License = LoadLicense(n); } },
             { "version",    (o,n) => { o.Version = new Version(n.GetScalarValue()); } }

src/Microsoft.OpenApi.Readers/YamlReaders/OpenApiV3Deserializer.cs

@@ -57,7 +57,7 @@ public static OpenApiDocument LoadOpenApi(RootNode rootNode)
             { "title",      (o,n) => { o.Title = n.GetScalarValue(); } },
             { "version",    (o,n) => { o.Version = new Version(n.GetScalarValue()); } },
             { "description", (o,n) => { o.Description = n.GetScalarValue(); } },
-            { "termsOfService", (o,n) => { o.TermsOfService = n.GetScalarValue(); } },
+            { "termsOfService", (o,n) => { o.TermsOfService = new Uri(n.GetScalarValue()); } },
             { "contact",    (o,n) => { o.Contact = LoadContact(n); } },
             { "license",    (o,n) => { o.License = LoadLicense(n); } }
         };

src/Microsoft.OpenApi.Workbench/MainModel.cs

@@ -121,18 +121,11 @@ internal void Validate()
 
         private string WriteContents(OpenApiDocument doc)
         {
-            Func<Stream, IOpenApiWriter> writerFactory = s => (this.format == "Yaml" ? new OpenApiYamlWriter(new StreamWriter(s)) : (IOpenApiWriter)new OpenApiJsonWriter(new StreamWriter(s)));
-            IOpenApiStructureWriter writer;
-            if (IsV3)
-            {
-                writer = new OpenApiV3Writer(writerFactory);
-            } else
-            {
-                writer = new OpenApiV2Writer(writerFactory);
-            }
-
             var outputstream = new MemoryStream();
-            writer.Write(outputstream, doc);
+            doc.Serialize(outputstream,
+                IsV3 ? OpenApiSpecVersion.OpenApi3_0 : OpenApiSpecVersion.OpenApi2_0,
+                this.format == "Yaml" ? OpenApiFormat.Yaml : OpenApiFormat.Json);
+
             outputstream.Position = 0;
 
             return new StreamReader(outputstream).ReadToEnd();

src/Microsoft.OpenApi/Models/OpenApiCallback.cs

@@ -6,18 +6,52 @@
 using System.Collections.Generic;
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Interfaces;
+using Microsoft.OpenApi.Writers;
 
 namespace Microsoft.OpenApi.Models
 {
     /// <summary>
     /// Callback Object: A map of possible out-of band callbacks related to the parent operation.
     /// </summary>
-    public class OpenApiCallback : IOpenApiReference, IOpenApiExtension
+    public class OpenApiCallback : OpenApiElement, IOpenApiReference, IOpenApiExtension
     {
         public Dictionary<RuntimeExpression, OpenApiPathItem> PathItems { get; set; } = new Dictionary<RuntimeExpression, OpenApiPathItem>();
 
         public OpenApiReference Pointer { get; set; }
 
         public IDictionary<string, IOpenApiAny> Extensions { get; set; }
+
+        /// <summary>
+        /// Serialize <see cref="OpenApiCallback"/> to Open Api v3.0
+        /// </summary>
+        internal override void WriteAsV3(IOpenApiWriter writer)
+        {
+            if (writer == null)
+            {
+                throw Error.ArgumentNull(nameof(writer));
+            }
+
+            if (this.IsReference())
+            {
+                this.WriteRef(writer);
+            }
+            else
+            {
+                writer.WriteStartObject();
+                foreach (var item in PathItems)
+                {
+                    writer.WriteObject<OpenApiPathItem>(item.Key.Expression, item.Value, (w, p) => p.WriteAsV3(w));
+                }
+                writer.WriteEndObject();
+            }
+        }
+
+        /// <summary>
+        /// Serialize <see cref="OpenApiCallback"/> to Open Api v2.0
+        /// </summary>
+        internal override void WriteAsV2(IOpenApiWriter writer)
+        {
+            // nothing here
+        }
     }
 }

src/Microsoft.OpenApi/Models/OpenApiComponents.cs

@@ -6,13 +6,14 @@
 using System.Collections.Generic;
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Interfaces;
+using Microsoft.OpenApi.Writers;
 
 namespace Microsoft.OpenApi.Models
 {
     /// <summary>
     /// Components Object.
     /// </summary>
-    public class OpenApiComponents : IOpenApiExtension
+    public class OpenApiComponents : OpenApiElement, IOpenApiExtension
     {
         public IDictionary<string, OpenApiSchema> Schemas { get; set; } = new Dictionary<string, OpenApiSchema>();
         public IDictionary<string, OpenApiResponse> Responses { get; set; } = new Dictionary<string, OpenApiResponse>();
@@ -37,5 +38,46 @@ public bool IsEmpty()
                 || this.Links.Count > 0
                 || this.Callbacks.Count > 0);
         }
+
+        /// <summary>
+        /// Serialize <see cref="OpenApiComponents"/> to Open Api v3.0
+        /// </summary>
+        internal override void WriteAsV3(IOpenApiWriter writer)
+        {
+            if (writer == null)
+            {
+                throw Error.ArgumentNull(nameof(writer));
+            }
+
+            writer.WriteStartObject();
+            writer.WriteMap("schemas", Schemas, (w, s) => s.WriteAsV3(w));
+            writer.WriteMap("responses", Responses, (w, r) => r.WriteAsV3(w));
+            writer.WriteMap("parameters", Parameters, (w, p) => p.WriteAsV3(w));
+            writer.WriteMap("examples", Examples, (w, e) => e.WriteAsV3(w));
+            writer.WriteMap("requestBodies", RequestBodies, (w, r) => r.WriteAsV3(w));
+            writer.WriteMap("headers", Headers, (w, h) => h.WriteAsV3(w));
+            writer.WriteMap("securitySchemes", SecuritySchemes, (w, s) => s.WriteAsV3(w));
+            writer.WriteMap("links", Links, (w, link) => link.WriteAsV3(w));
+            writer.WriteMap("callbacks", Callbacks, (w, c) => c.WriteAsV3(w));
+            writer.WriteEndObject();
+        }
+
+        /// <summary>
+        /// Serialize <see cref="OpenApiComponents"/> to Open Api v2.0
+        /// </summary>
+        internal override void WriteAsV2(IOpenApiWriter writer)
+        {
+            if (writer == null)
+            {
+                throw Error.ArgumentNull(nameof(writer));
+            }
+
+            writer.WriteStartObject();
+            writer.WriteMap("definitions", Schemas, (w, s) => s.WriteAsV2(w));
+            writer.WriteMap("responses", Responses, (w, r) => r.WriteAsV2(w));
+            writer.WriteMap("parameters", Parameters, (w, p) => p.WriteAsV2(w));
+            writer.WriteMap("securityDefinitions", SecuritySchemes, (w, s) => s.WriteAsV2(w));
+            writer.WriteEndObject();
+        }
     }
 }

src/Microsoft.OpenApi/Models/OpenApiConstants.cs

@@ -0,0 +1,216 @@
+// ------------------------------------------------------------
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// ------------------------------------------------------------
+
+using System;
+
+namespace Microsoft.OpenApi.Models
+{
+    internal static class OpenApiConstants
+    {
+        public const string OpenApiDocOpenApi = "openapi";
+
+        public const string OpenApiDocInfo = "info";
+
+        public const string OpenApiDocTitle = "title";
+
+        public const string OpenApiDocType = "type";
+
+        public const string OpenApiDocFormat = "format";
+
+        public const string OpenApiDocVersion = "version";
+
+        public const string OpenApiDocContact = "contact";
+
+        public const string OpenApiDocLicense = "license";
+
+        public const string OpenApiDocTermsOfService = "termsOfService";
+
+        public const string OpenApiDocServers = "servers";
+
+        public const string OpenApiDocServer = "server";
+
+        public const string OpenApiDocPaths = "paths";
+
+        public const string OpenApiDocComponents = "components";
+
+        public const string OpenApiDocSecurity = "security";
+
+        public const string OpenApiDocTags = "tags";
+
+        public const string OpenApiDocExternalDocs = "externalDocs";
+
+        public const string OpenApiDocOperationRef = "operationRef";
+
+        public const string OpenApiDocOperationId = "operationId";
+
+        public const string OpenApiDocParameters = "parameters";
+
+        public const string OpenApiDocRequestBody = "requestBody";
+
+        public const string OpenApiDocExtensionFieldNamePrefix = "x-";
+
+        public const string OpenApiDocName = "name";
+
+        public const string OpenApiDocIn = "in";
+
+        public const string OpenApiDocSummary = "summary";
+
+        public const string OpenApiDocVariables = "variables";
+
+        public const string OpenApiDocDescription = "description";
+
+        public const string OpenApiDocRequired = "required";
+
+        public const string OpenApiDocDeprecated = "deprecated";
+
+        public const string OpenApiDocStyle = "style";
+
+        public const string OpenApiDocExplode = "explode";
+
+        public const string OpenApiDocAllowReserved = "allowReserved";
+
+        public const string OpenApiDocSchema = "schema";
+
+        public const string OpenApiDocSchemas = "schemas";
+
+        public const string OpenApiDocResponses = "responses";
+
+        public const string OpenApiDocExample = "example";
+
+        public const string OpenApiDocExamples = "examples";
+
+        public const string OpenApiDocEncoding = "encoding";
+
+        public const string OpenApiDocRequestBodies = "requestBodies";
+
+        public const string OpenApiDocAllowEmptyValue = "allowEmptyValue";
+
+        public const string OpenApiDocValue = "value";
+
+        public const string OpenApiDocExternalValue = "externalValue";
+
+        public const string OpenApiDocDollarRef = "$ref";
+
+        public const string OpenApiDocHeaders = "headers";
+
+        public const string OpenApiDocSecuritySchemes = "securitySchemes";
+
+        public const string OpenApiDocContent = "content";
+
+        public const string OpenApiDocLinks = "links";
+
+        public const string OpenApiDocCallbacks = "callbacks";
+
+        public const string OpenApiDocUrl = "url";
+
+        public const string OpenApiDocEmail = "email";
+
+        public const string OpenApiDocDefault = "default";
+
+        public const string OpenApiDocEnum = "enum";
+
+        public const string OpenApiDocMultipleOf = "multipleOf";
+
+        public const string OpenApiDocMaximum = "maximum";
+
+        public const string OpenApiDocExclusiveMaximum = "exclusiveMaximum";
+
+        public const string OpenApiDocMinimum = "minimum";
+
+        public const string OpenApiDocExclusiveMinimum = "exclusiveMinimum";
+
+        public const string OpenApiDocMaxLength = "maxLength";
+
+        public const string OpenApiDocMinLength = "minLength";
+
+        public const string OpenApiDocPattern = "pattern";
+
+        public const string OpenApiDocMaxItems = "maxItems";
+
+        public const string OpenApiDocMinItems = "minItems";
+
+        public const string OpenApiDocUniqueItems = "uniqueItems";
+
+        public const string OpenApiDocMaxProperties = "maxProperties";
+
+        public const string OpenApiDocMinProperties = "minProperties";
+
+        public const string OpenApiDocAllOf = "allOf";
+
+        public const string OpenApiDocOneOf = "oneOf";
+
+        public const string OpenApiDocAnyOf = "anyOf";
+
+        public const string OpenApiDocNot = "not";
+
+        public const string OpenApiDocItems = "items";
+
+        public const string OpenApiDocProperties = "properties";
+
+        public const string OpenApiDocAdditionalProperties = "additionalProperties";
+
+        public const string OpenApiDocNullable = "nullable";
+
+        public const string OpenApiDocDiscriminator = "discriminator";
+
+        public const string OpenApiDocReadOnly = "readOnly";
+
+        public const string OpenApiDocWriteOnly = "writeOnly";
+
+        public const string OpenApiDocXml = "xml";
+
+        public const string OpenApiDocFlow = "flow";
+
+        public const string OpenApiDocApplication = "application";
+
+        public const string OpenApiDocAccessCode = "accessCode";
+
+        public const string OpenApiDocImplicit = "implicit";
+
+        public const string OpenApiDocPassword = "password";
+
+        public const string OpenApiDocClientCredentials = "clientCredentials";
+
+        public const string OpenApiDocAuthorizationCode = "authorizationCode";
+
+        public const string OpenApiDocAuthorizationUrl = "authorizationUrl";
+
+        public const string OpenApiDocTokenUrl = "tokenUrl";
+
+        public const string OpenApiDocRefreshUrl = "refreshUrl";
+
+        public const string OpenApiDocScopes = "scopes";
+
+        public const string OpenApiDocContentType = "contentType";
+
+        public const string OpenApiDocGet = "get";
+
+        public const string OpenApiDocPut = "put";
+
+        public const string OpenApiDocPost = "post";
+
+        public const string OpenApiDocDelete = "delete";
+
+        public const string OpenApiDocOptions = "options";
+
+        public const string OpenApiDocHead = "head";
+
+        public const string OpenApiDocPatch = "patch";
+
+        public const string OpenApiDocTrace = "trace";
+
+        public const string OpenApiDocDefaultName = "Default Name";
+
+        public const string OpenApiDocDefaultDefault = "Default Default";
+
+        public const string OpenApiDocDefaultTitle = "Default Title";
+
+        public static Version OpenApiDocDefaultVersion = new Version(3, 0, 0);
+
+        public static Uri OpenApiDocDefaultUrl = new Uri("http://localhost/");
+
+        public const string OpenApiDocDefaultDescription = "Default Description";
+    }
+}