Allow use of System.Text.Json in Request/Response examples.

.editorconfig

@@ -25,4 +25,4 @@ trim_trailing_whitespace = true
 [NuGet.Config]
 indent_style = space
 indent_size = 2
-trim_trailing_whitespace = true
+trim_trailing_whitespace = true

.gitignore

@@ -18,3 +18,6 @@ _ReSharper.*
 # Visual Studio 2015 cache/options directory
 .vs/
 *.nupkg
+
+# Rider settings directory
+.idea

src/Swashbuckle.AspNetCore.Filters/Examples/ExamplesConverter.cs

@@ -10,15 +10,13 @@ namespace Swashbuckle.AspNetCore.Filters
 {
     internal class ExamplesConverter
     {
-        private readonly JsonFormatter jsonFormatter;
+        private readonly IJsonFormatter jsonFormatter;
         private readonly MvcOutputFormatter mvcOutputFormatter;
-        private readonly JsonSerializerSettings serializerSettings;
 
-        public ExamplesConverter(JsonFormatter jsonFormatter, MvcOutputFormatter mvcOutputFormatter, JsonSerializerSettings serializerSettings)
+        public ExamplesConverter(IJsonFormatter jsonFormatter, MvcOutputFormatter mvcOutputFormatter)
         {
             this.jsonFormatter = jsonFormatter;
             this.mvcOutputFormatter = mvcOutputFormatter;
-            this.serializerSettings = serializerSettings;
         }
 
         public IOpenApiAny SerializeExampleXml(object exampleValue)
@@ -28,7 +26,7 @@ public IOpenApiAny SerializeExampleXml(object exampleValue)
 
         public IOpenApiAny SerializeExampleJson(object exampleValue)
         {
-            return new OpenApiRawString(jsonFormatter.FormatJson(exampleValue, serializerSettings));
+            return new OpenApiRawString(jsonFormatter.FormatJson(exampleValue));
         }
 
         private static IDictionary<string, OpenApiExample> ToOpenApiExamplesDictionary(

src/Swashbuckle.AspNetCore.Filters/Examples/IJsonFormatter.cs

@@ -0,0 +1,7 @@
+namespace Swashbuckle.AspNetCore.Filters
+{
+    internal interface IJsonFormatter
+    {
+        string FormatJson(object examples);
+    }
+}

src/Swashbuckle.AspNetCore.Filters/Examples/JsonFormatterProvider.cs

@@ -0,0 +1,48 @@
+using System.Linq;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Formatters;
+using Microsoft.Extensions.Options;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Serialization;
+
+namespace Swashbuckle.AspNetCore.Filters
+{
+    internal class JsonFormatterProvider
+    {
+        private readonly SerializerSettingsDuplicator serializerSettingsDuplicator;
+        private readonly SerializerOptionsDuplicator serializerOptionsDuplicator;
+        private readonly SerializationMode defaultSerializationMode;
+
+        public JsonFormatterProvider(SerializerSettingsDuplicator serializerSettingsDuplicator, SerializerOptionsDuplicator serializerOptionsDuplicator, IOptions<MvcOptions> mvcOptions)
+        {
+            this.serializerSettingsDuplicator = serializerSettingsDuplicator;
+            this.serializerOptionsDuplicator = serializerOptionsDuplicator;
+
+#if NETCOREAPP3_0
+            // NewtonsoftJsonFormatter will be present if consumer has called UseNewtonsoftJson in Startup.cs
+            defaultSerializationMode = mvcOptions.Value.OutputFormatters.Any(x => x.GetType() == typeof(NewtonsoftJsonOutputFormatter))
+                ? SerializationMode.Newtonsoft
+                : SerializationMode.SystemTextJson;
+#else
+            defaultSerializationMode = SerializationMode.Newtonsoft;
+#endif
+        }
+
+        public IJsonFormatter GetFormatter(IContractResolver contractResolver = null, JsonConverter jsonConverter = null)
+        {
+            if (UseNewtonsoft(contractResolver, jsonConverter))
+                return new NewtonsoftJsonFormatter(serializerSettingsDuplicator.SerializerSettings(contractResolver, jsonConverter));
+
+            return new SystemTextJsonFormatter(serializerOptionsDuplicator.SerializerOptions());
+        }
+
+        private bool UseNewtonsoft(IContractResolver contractResolver = null, JsonConverter jsonConverter = null) =>
+            defaultSerializationMode == SerializationMode.Newtonsoft || contractResolver != null || jsonConverter != null;
+    }
+
+    public enum SerializationMode
+    {
+        Newtonsoft,
+        SystemTextJson
+    }
+}

src/Swashbuckle.AspNetCore.Filters/Examples/NewtonsoftJsonFormatter.cs

@@ -0,0 +1,20 @@
+using Newtonsoft.Json;
+
+namespace Swashbuckle.AspNetCore.Filters
+{
+    internal class NewtonsoftJsonFormatter : IJsonFormatter
+    {
+        private readonly JsonSerializerSettings serializerSettings;
+
+        public NewtonsoftJsonFormatter(JsonSerializerSettings serializerSettings)
+        {
+            serializerSettings.Formatting = Formatting.Indented;
+            this.serializerSettings = serializerSettings;
+        }
+
+        public string FormatJson(object examples)
+        {
+            return JsonConvert.SerializeObject(examples, serializerSettings);
+        }
+    }
+}

src/Swashbuckle.AspNetCore.Filters/Examples/RequestExample.cs

@@ -14,19 +14,16 @@ namespace Swashbuckle.AspNetCore.Filters
 {
     internal class RequestExample
     {
-        private readonly JsonFormatter jsonFormatter;
-        private readonly SerializerSettingsDuplicator serializerSettingsDuplicator;
+        private readonly JsonFormatterProvider jsonFormatterProvider;
         private readonly MvcOutputFormatter mvcOutputFormatter;
         private readonly SwaggerOptions swaggerOptions;
 
         public RequestExample(
-            JsonFormatter jsonFormatter,
-            SerializerSettingsDuplicator serializerSettingsDuplicator,
+            JsonFormatterProvider jsonFormatterProvider,
             MvcOutputFormatter mvcOutputFormatter,
             IOptions<SwaggerOptions> options)
         {
-            this.jsonFormatter = jsonFormatter;
-            this.serializerSettingsDuplicator = serializerSettingsDuplicator;
+            this.jsonFormatterProvider = jsonFormatterProvider;
             this.mvcOutputFormatter = mvcOutputFormatter;
             this.swaggerOptions = options?.Value;
         }
@@ -49,9 +46,9 @@ public void SetRequestExampleForOperation(
                 return;
             }
 
-            var serializerSettings = serializerSettingsDuplicator.SerializerSettings(contractResolver, jsonConverter);
+            var jsonFormatter = jsonFormatterProvider.GetFormatter(contractResolver, jsonConverter);
 
-            var examplesConverter = new ExamplesConverter(jsonFormatter, mvcOutputFormatter, serializerSettings);
+            var examplesConverter = new ExamplesConverter(jsonFormatter, mvcOutputFormatter);
 
             IOpenApiAny firstOpenApiExample;
             var multiple = example as IEnumerable<ISwaggerExample<object>>;
@@ -140,4 +137,4 @@ private IOpenApiAny SetMultipleRequestExamplesForOperation(
             return operation.RequestBody.Content.FirstOrDefault().Value?.Examples?.FirstOrDefault().Value?.Value;
         }
     }
-}
+}

src/Swashbuckle.AspNetCore.Filters/Examples/ResponseExample.cs

@@ -10,17 +10,14 @@ namespace Swashbuckle.AspNetCore.Filters
 {
     internal class ResponseExample
     {
-        private readonly JsonFormatter jsonFormatter;
-        private readonly SerializerSettingsDuplicator serializerSettingsDuplicator;
+        private readonly JsonFormatterProvider jsonFormatterProvider;
         private readonly MvcOutputFormatter mvcOutputFormatter;
 
         public ResponseExample(
-            JsonFormatter jsonFormatter,
-            SerializerSettingsDuplicator serializerSettingsDuplicator,
+            JsonFormatterProvider jsonFormatterProvider,
             MvcOutputFormatter mvcOutputFormatter)
         {
-            this.jsonFormatter = jsonFormatter;
-            this.serializerSettingsDuplicator = serializerSettingsDuplicator;
+            this.jsonFormatterProvider = jsonFormatterProvider;
             this.mvcOutputFormatter = mvcOutputFormatter;
         }
 
@@ -42,9 +39,9 @@ public void SetResponseExampleForStatusCode(
                 return;
             }
 
-            var serializerSettings = serializerSettingsDuplicator.SerializerSettings(contractResolver, jsonConverter);
+            var jsonFormatter = jsonFormatterProvider.GetFormatter(contractResolver, jsonConverter);
 
-            var examplesConverter = new ExamplesConverter(jsonFormatter, mvcOutputFormatter, serializerSettings);
+            var examplesConverter = new ExamplesConverter(jsonFormatter, mvcOutputFormatter);
 
             var multiple = example as IEnumerable<ISwaggerExample<object>>;
             if (multiple == null)
@@ -56,7 +53,7 @@ public void SetResponseExampleForStatusCode(
                 SetMultipleResponseExampleForStatusCode(response, multiple, examplesConverter);
             }
         }
-        
+
         private void SetSingleResponseExampleForStatusCode(
             KeyValuePair<string, OpenApiResponse> response,
             object example,

src/Swashbuckle.AspNetCore.Filters/Examples/SerializerOptionsDuplicator.cs

@@ -0,0 +1,70 @@
+using System.Text.Json;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Options;
+using Swashbuckle.AspNetCore.SwaggerGen;
+
+namespace Swashbuckle.AspNetCore.Filters
+{
+    internal class SerializerOptionsDuplicator
+    {
+        private readonly JsonSerializerOptions jsonSerializerOptions;
+        private readonly SchemaGeneratorOptions schemaGeneratorOptions;
+
+
+#if NETCOREAPP3_0
+        public SerializerOptionsDuplicator(IOptions<JsonOptions> jsonOptions, IOptions<SchemaGeneratorOptions> schemaGeneratorOptions)
+        {
+            this.jsonSerializerOptions = jsonOptions.Value.JsonSerializerOptions;
+            this.schemaGeneratorOptions = schemaGeneratorOptions.Value;
+        }
+#else
+        public SerializerOptionsDuplicator(IOptions<SchemaGeneratorOptions> schemaGeneratorOptions)
+        {
+            this.jsonSerializerOptions = new JsonSerializerOptions();
+            this.schemaGeneratorOptions = schemaGeneratorOptions.Value;
+        }
+#endif
+
+        public JsonSerializerOptions SerializerOptions()
+        {
+            var serializerSettings = DuplicateSerializerSettings(jsonSerializerOptions);
+
+            if (schemaGeneratorOptions.IgnoreObsoleteProperties)
+            {
+                // TODO THIS
+            }
+
+            return serializerSettings;
+        }
+
+        private static JsonSerializerOptions DuplicateSerializerSettings(JsonSerializerOptions controllerSerializerOptions)
+        {
+            if (controllerSerializerOptions == null)
+            {
+                return new JsonSerializerOptions();
+            }
+
+            var options = new JsonSerializerOptions
+            {
+                Encoder = controllerSerializerOptions.Encoder,
+                MaxDepth = controllerSerializerOptions.MaxDepth,
+                WriteIndented = controllerSerializerOptions.WriteIndented,
+                AllowTrailingCommas = controllerSerializerOptions.AllowTrailingCommas,
+                DefaultBufferSize = controllerSerializerOptions.DefaultBufferSize,
+                DictionaryKeyPolicy = controllerSerializerOptions.DictionaryKeyPolicy,
+                IgnoreNullValues = controllerSerializerOptions.IgnoreNullValues,
+                PropertyNamingPolicy = controllerSerializerOptions.PropertyNamingPolicy,
+                ReadCommentHandling = controllerSerializerOptions.ReadCommentHandling,
+                IgnoreReadOnlyProperties = controllerSerializerOptions.IgnoreReadOnlyProperties,
+                PropertyNameCaseInsensitive = controllerSerializerOptions.PropertyNameCaseInsensitive
+            };
+
+            foreach (var converter in controllerSerializerOptions.Converters)
+            {
+                options.Converters.Add(converter);
+            }
+
+            return options;
+        }
+    }
+}

src/Swashbuckle.AspNetCore.Filters/Examples/SystemTextJsonFormatter.cs

@@ -0,0 +1,20 @@
+using System.Text.Json;
+
+namespace Swashbuckle.AspNetCore.Filters
+{
+    internal class SystemTextJsonFormatter : IJsonFormatter
+    {
+        private readonly JsonSerializerOptions serializerOptions;
+
+        public SystemTextJsonFormatter(JsonSerializerOptions serializerOptions)
+        {
+            serializerOptions.WriteIndented = true;
+            this.serializerOptions = serializerOptions;
+        }
+
+        public string FormatJson(object examples)
+        {
+            return JsonSerializer.Serialize(examples, serializerOptions);
+        }
+    }
+}

src/Swashbuckle.AspNetCore.Filters/Extensions/ServiceCollectionExtensions.cs

@@ -77,12 +77,13 @@ public static IServiceCollection AddSwaggerExamplesFromAssemblies(this IServiceC
         private static void AddRequiredServices(IServiceCollection services)
         {
             services.AddSingleton<SerializerSettingsDuplicator>();
-            services.AddSingleton<JsonFormatter>();
+            services.AddSingleton<SerializerOptionsDuplicator>();
+            services.AddSingleton<JsonFormatterProvider>();
             services.AddSingleton<RequestExample>();
             services.AddSingleton<ResponseExample>();
             services.AddSingleton<ExamplesOperationFilter>();
             services.AddSingleton<ServiceProviderExamplesOperationFilter>();
             services.AddSingleton<MvcOutputFormatter>();
         }
     }
-}
+}

test/Swashbuckle.AspNetCore.Filters.Test/Examples/ExamplesOperationFilterTests.cs

@@ -25,11 +25,13 @@ public class ExamplesOperationFilterTests : BaseOperationFilterTests
 
         public ExamplesOperationFilterTests()
         {
-            var mvcJsonOptions = Options.Create(new MvcJsonOptions());
             schemaGeneratorOptions = new SchemaGeneratorOptions();
+            var mvcJsonOptions = Options.Create(new MvcJsonOptions());
+            var mvcOptions = Options.Create(new MvcOptions());
             var serializerSettingsDuplicator = new SerializerSettingsDuplicator(mvcJsonOptions, Options.Create(schemaGeneratorOptions));
+            var serializerOptionsDuplicator = new SerializerOptionsDuplicator(Options.Create(schemaGeneratorOptions));
 
-            var jsonFormatter = new JsonFormatter();
+            var jsonFormatter = new JsonFormatterProvider(serializerSettingsDuplicator, serializerOptionsDuplicator, mvcOptions);
             var mvcOutputFormatter = new MvcOutputFormatter(FormatterOptions.WithoutFormatters, new FakeLoggerFactory());
 
             var serviceProvider = Substitute.For<IServiceProvider>();
@@ -39,8 +41,8 @@ public ExamplesOperationFilterTests()
             serviceProvider.GetService(typeof(PersonRequestMultipleExamples)).Returns(new PersonRequestMultipleExamples());
             serviceProvider.GetService(typeof(DictionaryRequestExample)).Returns(new DictionaryRequestExample());
 
-            var requestExample = new RequestExample(jsonFormatter, serializerSettingsDuplicator, mvcOutputFormatter, Options.Create(swaggerOptions));
-            var responseExample = new ResponseExample(jsonFormatter, serializerSettingsDuplicator, mvcOutputFormatter);
+            var requestExample = new RequestExample(jsonFormatter, mvcOutputFormatter, Options.Create(swaggerOptions));
+            var responseExample = new ResponseExample(jsonFormatter, mvcOutputFormatter);
 
             sut = new ExamplesOperationFilter(serviceProvider, requestExample, responseExample);
         }

test/Swashbuckle.AspNetCore.Filters.Test/Examples/ServiceProviderExamplesOperationFilterTests.cs

@@ -26,15 +26,18 @@ public class ServiceProviderExamplesOperationFilterTests : BaseOperationFilterTe
 
         public ServiceProviderExamplesOperationFilterTests()
         {
-            var mvcJsonOptions = Options.Create(new MvcJsonOptions());
             schemaGeneratorOptions = new SchemaGeneratorOptions();
+
+            var mvcJsonOptions = Options.Create(new MvcJsonOptions());
+            var mvcOptions = Options.Create(new MvcOptions());
             var serializerSettingsDuplicator = new SerializerSettingsDuplicator(mvcJsonOptions, Options.Create(schemaGeneratorOptions));
+            var serializerOptionsDuplicator = new SerializerOptionsDuplicator(Options.Create(schemaGeneratorOptions));
 
-            var jsonFormatter = new JsonFormatter();
+            var jsonFormatter = new JsonFormatterProvider(serializerSettingsDuplicator, serializerOptionsDuplicator, mvcOptions);
             var mvcOutputFormatter = new MvcOutputFormatter(FormatterOptions.WithoutFormatters, new FakeLoggerFactory());
 
-            var requestExample = new RequestExample(jsonFormatter, serializerSettingsDuplicator, mvcOutputFormatter, Options.Create(swaggerOptions));
-            var responseExample = new ResponseExample(jsonFormatter, serializerSettingsDuplicator, mvcOutputFormatter);
+            var requestExample = new RequestExample(jsonFormatter, mvcOutputFormatter, Options.Create(swaggerOptions));
+            var responseExample = new ResponseExample(jsonFormatter, mvcOutputFormatter);
 
             serviceProvider = Substitute.For<IServiceProvider>();
             serviceProvider.GetService(typeof(IExamplesProvider<PersonResponse>)).Returns(new PersonResponseAutoExample());