Deprecate SerializeAsV2

README.md

@@ -305,7 +305,7 @@ By default, Swashbuckle will generate and expose Swagger JSON in version 3.0 of
 ```csharp
 app.UseSwagger(c =>
 {
-    c.SerializeAsV2 = true;
+    c.OpenApiVersion = Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0;
 });
 ```
 

src/Swashbuckle.AspNetCore.Cli/Program.cs

@@ -8,13 +8,17 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Options;
+using Microsoft.OpenApi;
 using Microsoft.OpenApi.Writers;
 using Swashbuckle.AspNetCore.Swagger;
 
 namespace Swashbuckle.AspNetCore.Cli
 {
     internal class Program
     {
+        private const string OpenApiVersionOption = "--openapiversion";
+        private const string SerializeAsV2Flag = "--serializeasv2";
+
         public static int Main(string[] args)
         {
             // Helper to simplify command line parsing etc.
@@ -26,25 +30,28 @@ public static int Main(string[] args)
             // startupassembly and it's transitive dependencies. See https://github.com/dotnet/coreclr/issues/13277 for more.
 
             // > dotnet swagger tofile ...
-            runner.SubCommand("tofile", "retrieves Swagger from a startup assembly, and writes to file ", c =>
+            runner.SubCommand("tofile", "retrieves Swagger from a startup assembly, and writes to file", c =>
             {
                 c.Argument("startupassembly", "relative path to the application's startup assembly");
                 c.Argument("swaggerdoc", "name of the swagger doc you want to retrieve, as configured in your startup class");
 
                 c.Option("--output", "relative path where the Swagger will be output, defaults to stdout");
                 c.Option("--host", "a specific host to include in the Swagger output");
                 c.Option("--basepath", "a specific basePath to include in the Swagger output");
-                c.Option("--serializeasv2", "output Swagger in the V2 format rather than V3", true);
+                c.Option(OpenApiVersionOption, "output Swagger in the specified version, defaults to 3.0");
                 c.Option("--yaml", "exports swagger in a yaml format", true);
 
+                // TODO Remove this option in the major version that adds support for OpenAPI 3.1
+                c.Option(SerializeAsV2Flag, "output Swagger in the V2 format rather than V3 [deprecated]", true);
+
                 c.OnRun((namedArgs) =>
                 {
                     string subProcessCommandLine = PrepareCommandLine(args, namedArgs);
 
-                    var subProcess = Process.Start("dotnet", subProcessCommandLine);
+                    using var child = Process.Start("dotnet", subProcessCommandLine);
 
-                    subProcess.WaitForExit();
-                    return subProcess.ExitCode;
+                    child.WaitForExit();
+                    return child.ExitCode;
                 });
             });
 
@@ -56,8 +63,12 @@ public static int Main(string[] args)
                 c.Option("--output", "");
                 c.Option("--host", "");
                 c.Option("--basepath", "");
-                c.Option("--serializeasv2", "", true);
+                c.Option(OpenApiVersionOption, "");
                 c.Option("--yaml", "", true);
+
+                // TODO Remove this option in the major version that adds support for OpenAPI 3.1
+                c.Option(SerializeAsV2Flag, "", true);
+
                 c.OnRun((namedArgs) =>
                 {
                     SetupAndRetrieveSwaggerProviderAndOptions(namedArgs, out var swaggerProvider, out var swaggerOptions);
@@ -94,24 +105,40 @@ public static int Main(string[] args)
                         writer = new OpenApiJsonWriter(streamWriter);
                     }
 
-                    if (namedArgs.ContainsKey("--serializeasv2"))
+                    OpenApiSpecVersion specVersion = OpenApiSpecVersion.OpenApi3_0;
+
+                    if (namedArgs.TryGetValue(OpenApiVersionOption, out var versionArg))
                     {
-                        if (swaggerDocumentSerializer != null)
+                        specVersion = versionArg switch
                         {
-                            swaggerDocumentSerializer.SerializeDocument(swagger, writer, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0);
-                        }
-                        else
-                        {
-                            swagger.SerializeAsV2(writer);
-                        }
+                            "2.0" => OpenApiSpecVersion.OpenApi2_0,
+                            "3.0" => OpenApiSpecVersion.OpenApi3_0,
+                            _ => throw new NotSupportedException($"The specified OpenAPI version \"{versionArg}\" is not supported."),
+                        };
                     }
-                    else if (swaggerDocumentSerializer != null)
+                    else if (namedArgs.ContainsKey(SerializeAsV2Flag))
+                    {
+                        specVersion = OpenApiSpecVersion.OpenApi2_0;
+                        WriteSerializeAsV2DeprecationWarning();
+                    }
+
+                    if (swaggerDocumentSerializer != null)
                     {
-                        swaggerDocumentSerializer.SerializeDocument(swagger, writer, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi3_0);
+                        swaggerDocumentSerializer.SerializeDocument(swagger, writer, specVersion);
                     }
                     else
                     {
-                        swagger.SerializeAsV3(writer);
+                        switch (specVersion)
+                        {
+                            case OpenApiSpecVersion.OpenApi2_0:
+                                swagger.SerializeAsV2(writer);
+                                break;
+
+                            case OpenApiSpecVersion.OpenApi3_0:
+                            default:
+                                swagger.SerializeAsV3(writer);
+                                break;
+                        }
                     }
 
                     if (outputPath != null)
@@ -132,10 +159,10 @@ public static int Main(string[] args)
                 {
                     string subProcessCommandLine = PrepareCommandLine(args, namedArgs);
 
-                    var subProcess = Process.Start("dotnet", subProcessCommandLine);
+                    using var child = Process.Start("dotnet", subProcessCommandLine);
 
-                    subProcess.WaitForExit();
-                    return subProcess.ExitCode;
+                    child.WaitForExit();
+                    return child.ExitCode;
                 });
             });
 
@@ -147,7 +174,7 @@ public static int Main(string[] args)
                 c.OnRun((namedArgs) =>
                 {
                     SetupAndRetrieveSwaggerProviderAndOptions(namedArgs, out var swaggerProvider, out var swaggerOptions);
-                    IList<string> docNames = new List<string>();
+                    IList<string> docNames = [];
 
                     string outputPath = namedArgs.TryGetValue("--output", out var arg1)
                         ? Path.Combine(Directory.GetCurrentDirectory(), arg1)
@@ -185,7 +212,7 @@ public static int Main(string[] args)
             return runner.Run(args);
         }
 
-        private static void SetupAndRetrieveSwaggerProviderAndOptions(System.Collections.Generic.IDictionary<string, string> namedArgs, out ISwaggerProvider swaggerProvider, out IOptions<SwaggerOptions> swaggerOptions)
+        private static void SetupAndRetrieveSwaggerProviderAndOptions(IDictionary<string, string> namedArgs, out ISwaggerProvider swaggerProvider, out IOptions<SwaggerOptions> swaggerOptions)
         {
             // 1) Configure host with provided startupassembly
             var startupAssembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(
@@ -199,7 +226,7 @@ private static void SetupAndRetrieveSwaggerProviderAndOptions(System.Collections
             swaggerOptions = serviceProvider.GetService<IOptions<SwaggerOptions>>();
         }
 
-        private static string PrepareCommandLine(string[] args, System.Collections.Generic.IDictionary<string, string> namedArgs)
+        private static string PrepareCommandLine(string[] args, IDictionary<string, string> namedArgs)
         {
             if (!File.Exists(namedArgs["startupassembly"]))
             {
@@ -222,7 +249,7 @@ private static string PrepareCommandLine(string[] args, System.Collections.Gener
                 EscapePath(runtimeConfig),
                 EscapePath(typeof(Program).GetTypeInfo().Assembly.Location),
                 commandName,
-                string.Join(" ", subProcessArguments.Select(x => EscapePath(x)))
+                string.Join(" ", subProcessArguments.Select(EscapePath))
             );
             return subProcessCommandLine;
         }
@@ -301,5 +328,21 @@ private static bool TryGetCustomHost<THost>(
             host = (THost)factoryMethod.Invoke(null, null);
             return true;
         }
+
+        private static void WriteSerializeAsV2DeprecationWarning()
+        {
+            const string AppName = "Swashbuckle.AspNetCore.Cli";
+
+            string message = $"The {SerializeAsV2Flag} flag will be removed in a future version of {AppName}. Use the {OpenApiVersionOption} option instead.";
+
+            Console.WriteLine(message);
+
+            // See https://docs.github.com/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions#setting-a-warning-message
+            // and https://docs.github.com/actions/writing-workflows/choosing-what-your-workflow-does/store-information-in-variables#default-environment-variables
+            if (Environment.GetEnvironmentVariable("GITHUB_ACTIONS") is "true")
+            {
+                Console.WriteLine($"::warning title={AppName}::{message}");
+            }
+        }
     }
 }

src/Swashbuckle.AspNetCore.Swagger/DependencyInjection/SwaggerBuilderExtensions.cs

@@ -53,22 +53,22 @@ public static IEndpointConventionBuilder MapSwagger(
                 throw new ArgumentException("Pattern must contain '{documentName}' parameter", nameof(pattern));
             }
 
-            Action<SwaggerOptions> endpointSetupAction = options =>
+            var pipeline = endpoints.CreateApplicationBuilder()
+                .UseSwagger(Configure)
+                .Build();
+
+            return endpoints.MapGet(pattern, pipeline);
+
+            void Configure(SwaggerOptions options)
             {
                 var endpointOptions = new SwaggerEndpointOptions();
 
                 setupAction?.Invoke(endpointOptions);
 
                 options.RouteTemplate = pattern;
-                options.SerializeAsV2 = endpointOptions.SerializeAsV2;
+                options.OpenApiVersion = endpointOptions.OpenApiVersion;
                 options.PreSerializeFilters.AddRange(endpointOptions.PreSerializeFilters);
-            };
-
-            var pipeline = endpoints.CreateApplicationBuilder()
-                .UseSwagger(endpointSetupAction)
-                .Build();
-
-            return endpoints.MapGet(pattern, pipeline);
+            }
         }
 #endif
     }

src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Shipped.txt

@@ -15,17 +15,13 @@ Swashbuckle.AspNetCore.Swagger.ISwaggerDocumentMetadataProvider
 Swashbuckle.AspNetCore.Swagger.ISwaggerDocumentMetadataProvider.GetDocumentNames() -> System.Collections.Generic.IList<string>
 Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions
 Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.PreSerializeFilters.get -> System.Collections.Generic.List<System.Action<Microsoft.OpenApi.Models.OpenApiDocument, Microsoft.AspNetCore.Http.HttpRequest>>
-Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
-Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
 Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SwaggerEndpointOptions() -> void
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.CustomDocumentSerializer.get -> Swashbuckle.AspNetCore.Swagger.ISwaggerDocumentSerializer
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.CustomDocumentSerializer.set -> void
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.PreSerializeFilters.get -> System.Collections.Generic.List<System.Action<Microsoft.OpenApi.Models.OpenApiDocument, Microsoft.AspNetCore.Http.HttpRequest>>
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.RouteTemplate.get -> string
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.RouteTemplate.set -> void
-Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
-Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SwaggerOptions() -> void
 Swashbuckle.AspNetCore.Swagger.UnknownSwaggerDocument
 Swashbuckle.AspNetCore.Swagger.UnknownSwaggerDocument.UnknownSwaggerDocument(string documentName, System.Collections.Generic.IEnumerable<string> knownDocuments) -> void

src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Unshipped.txt

@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.OpenApiVersion.get -> Microsoft.OpenApi.OpenApiSpecVersion
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.OpenApiVersion.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.OpenApiVersion.get -> Microsoft.OpenApi.OpenApiSpecVersion
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.OpenApiVersion.set -> void

src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net6.0/PublicAPI.Shipped.txt

@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void

src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net8.0/PublicAPI.Shipped.txt

@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void

src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net9.0/PublicAPI.Shipped.txt

@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void

src/Swashbuckle.AspNetCore.Swagger/PublicAPI/netstandard2.0/PublicAPI.Shipped.txt

@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void

src/Swashbuckle.AspNetCore.Swagger/SwaggerEndpointOptions.cs

@@ -1,4 +1,5 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
+using Microsoft.OpenApi;
 using Microsoft.OpenApi.Models;
 
 namespace Swashbuckle.AspNetCore.Swagger
@@ -7,15 +8,27 @@ public class SwaggerEndpointOptions
     {
         public SwaggerEndpointOptions()
         {
-            PreSerializeFilters = new List<Action<OpenApiDocument, HttpRequest>>();
-            SerializeAsV2 = false;
+            PreSerializeFilters = [];
+            OpenApiVersion = OpenApiSpecVersion.OpenApi3_0;
         }
 
+        /// <summary>
+        /// Return Swagger JSON/YAML in the V2.0 format rather than V3.0.
+        /// </summary>
+        [Obsolete($"This property will be removed in a future version of Swashbuckle.AspNetCore. Use the {nameof(OpenApiVersion)} property instead.")]
+        public bool SerializeAsV2
+        {
+            get => OpenApiVersion == OpenApiSpecVersion.OpenApi2_0;
+            set => OpenApiVersion = value ? OpenApiSpecVersion.OpenApi2_0 : OpenApiSpecVersion.OpenApi3_0;
+        }
 
         /// <summary>
-        /// Return Swagger JSON in the V2 format rather than V3
+        /// Gets or sets the OpenAPI (Swagger) document version to use.
         /// </summary>
-        public bool SerializeAsV2 { get; set; }
+        /// <remarks>
+        /// The default value is <see cref="OpenApiSpecVersion.OpenApi3_0"/>.
+        /// </remarks>
+        public OpenApiSpecVersion OpenApiVersion { get; set; }
 
         /// <summary>
         /// Actions that can be applied SwaggerDocument's before they're serialized to JSON.