Serialize JSON using camel case by default

- #4283
- update `JsonSerializerSettingsProvider` to choose the `CamelCaseNamingStrategy`

src/Microsoft.AspNetCore.Mvc.Formatters.Json/JsonSerializerSettingsProvider.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Newtonsoft.Json;
+using Newtonsoft.Json.Serialization;
 
 namespace Microsoft.AspNetCore.Mvc.Formatters
 {
@@ -20,6 +21,11 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
         {
             return new JsonSerializerSettings
             {
+                ContractResolver = new DefaultContractResolver
+                {
+                    NamingStrategy = new CamelCaseNamingStrategy(),
+                },
+
                 MissingMemberHandling = MissingMemberHandling.Ignore,
 
                 // Limit the object graph we'll consume to a fixed depth. This prevents stackoverflow exceptions
@@ -28,7 +34,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
 
                 // Do not change this setting
                 // Setting this to None prevents Json.NET from loading malicious, unsafe, or security-sensitive types
-                TypeNameHandling = TypeNameHandling.None
+                TypeNameHandling = TypeNameHandling.None,
             };
         }
     }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/BasicTests.cs

@@ -8,6 +8,7 @@ using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Reflection;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc.Formatters;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Serialization;
 using Xunit;
@@ -217,15 +218,10 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         }
 
         [Fact]
-        public async Task JsonHelper_RendersJson()
+        public async Task JsonHelper_RendersJson_WithCamelCaseNames()
         {
             // Arrange
-            var json = JsonConvert.SerializeObject(new BasicWebSite.Models.Person()
+            var json = "{\"id\":9000,\"fullName\":\"John <b>Smith</b>\"}";
-            {
-                Id = 9000,
-                Name = "John <b>Smith</b>"
-            });
-
             var expectedBody = string.Format(
                 @"<script type=""text/javascript"">
     var json = {0};
@@ -244,17 +240,10 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         }
 
         [Fact]
-        public async Task JsonHelperWithSettings_RendersJson()
+        public async Task JsonHelperWithSettings_RendersJson_WithNamesUnchanged()
         {
             // Arrange
-            var json = JsonConvert.SerializeObject(
+            var json = "{\"id\":9000,\"FullName\":\"John <b>Smith</b>\"}";
-                new BasicWebSite.Models.Person()
-                {
-                    Id = 9000,
-                    Name = "John <b>Smith</b>"
-                },
-                new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() });
-
             var expectedBody = string.Format(
                 @"<script type=""text/javascript"">
     var json = {0};
@@ -262,7 +251,29 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 json);
 
             // Act
-            var response = await Client.GetAsync("Home/JsonHelperWithSettingsInView");
+            var response = await Client.GetAsync("Home/JsonHelperWithSettingsInView?snakeCase=false");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+            Assert.Equal("text/html", response.Content.Headers.ContentType.MediaType);
+
+            var actualBody = await response.Content.ReadAsStringAsync();
+            Assert.Equal(expectedBody, actualBody, ignoreLineEndingDifferences: true);
+        }
+
+        [Fact]
+        public async Task JsonHelperWithSettings_RendersJson_WithSnakeCaseNames()
+        {
+            // Arrange
+            var json = "{\"id\":9000,\"full_name\":\"John <b>Smith</b>\"}";
+            var expectedBody = string.Format(
+                @"<script type=""text/javascript"">
+    var json = {0};
+</script>",
+                json);
+
+            // Act
+            var response = await Client.GetAsync("Home/JsonHelperWithSettingsInView?snakeCase=true");
 
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);

test/Microsoft.AspNetCore.Mvc.FunctionalTests/ContentNegotiationTest.cs

@@ -44,8 +44,8 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         {
             // Arrange
             var expectedContentType = MediaTypeHeaderValue.Parse("application/json;charset=utf-8");
-            var expectedBody = $"{{{Environment.NewLine}  \"Name\": \"My name\",{Environment.NewLine}" +
+            var expectedBody = $"{{{Environment.NewLine}  \"name\": \"My name\",{Environment.NewLine}" +
-                $"  \"Address\": \"My address\"{Environment.NewLine}}}";
+                $"  \"address\": \"My address\"{Environment.NewLine}}}";
 
             // Act
             var response = await Client.GetAsync("http://localhost/Normal/MultipleAllowedContentTypes");
@@ -90,7 +90,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         {
             // Arrange
             var expectedContentType = MediaTypeHeaderValue.Parse("application/json;charset=utf-8");
-            var expectedOutput = "{\"Name\":\"John\",\"Address\":\"One Microsoft Way\"}";
+            var expectedOutput = "{\"name\":\"John\",\"address\":\"One Microsoft Way\"}";
             var request = new HttpRequestMessage(
                 HttpMethod.Get,
                 "http://localhost/ContentNegotiation/UserInfo_ProducesWithTypeOnly");
@@ -287,7 +287,7 @@ END:VCARD
         {
             // Arrange
             var expectedContentType = MediaTypeHeaderValue.Parse("application/json;charset=utf-8");
-            var expectedBody = "{\"MethodName\":\"Produces_WithNonObjectResult\"}";
+            var expectedBody = "{\"methodName\":\"Produces_WithNonObjectResult\"}";
 
             // Act
             var response = await Client.GetAsync("http://localhost/ProducesJson/Produces_WithNonObjectResult");

test/Microsoft.AspNetCore.Mvc.FunctionalTests/JsonOutputFormatterTests.cs

@@ -7,6 +7,7 @@ using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Text;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc.Formatters;
 using Microsoft.AspNetCore.Testing.xunit;
 using Newtonsoft.Json;
 using Xunit;
@@ -35,7 +36,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 Name = "John Williams"
             };
 
-            var serializerSettings = new JsonSerializerSettings();
+            var serializerSettings = JsonSerializerSettingsProvider.CreateSerializerSettings();
             serializerSettings.Formatting = Formatting.Indented;
             var expectedBody = JsonConvert.SerializeObject(user, serializerSettings);
 

test/Microsoft.AspNetCore.Mvc.FunctionalTests/JsonResultTest.cs

@@ -31,7 +31,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             Assert.Equal("application/json", response.Content.Headers.ContentType.MediaType);
-            Assert.Equal("{\"Message\":\"hello\"}", content);
+            Assert.Equal("{\"message\":\"hello\"}", content);
         }
 
         // Using an Accept header can't force Json to not be Json. If your accept header doesn't jive with the
@@ -53,7 +53,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             Assert.Equal("application/json", response.Content.Headers.ContentType.MediaType);
-            Assert.Equal("{\"Message\":\"hello\"}", content);
+            Assert.Equal("{\"message\":\"hello\"}", content);
         }
 
         // If the object is null, it will get formatted as JSON. NOT as a 204/NoContent
@@ -122,7 +122,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             Assert.Equal("application/message+json", response.Content.Headers.ContentType.MediaType);
-            Assert.Equal("{\"Message\":\"hello\"}", content);
+            Assert.Equal("{\"message\":\"hello\"}", content);
         }
     }
 }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/RespectBrowserAcceptHeaderTests.cs

@@ -37,7 +37,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             Assert.NotNull(response.Content.Headers.ContentType);
             Assert.Equal("application/json; charset=utf-8", response.Content.Headers.ContentType.ToString());
             var responseData = await response.Content.ReadAsStringAsync();
-            Assert.Equal("{\"Id\":10,\"Name\":\"John\"}", responseData);
+            Assert.Equal("{\"id\":10,\"name\":\"John\"}", responseData);
         }
 
         [ConditionalTheory]
@@ -80,7 +80,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 "<RespectBrowserAcceptHeaderController.Employee xmlns:i=\"http://www.w3.org/2001/XMLSchema-instance\"" +
                 " xmlns=\"http://schemas.datacontract.org/2004/07/FormatterWebSite.Controllers\"><Id>35</Id><Name>Jimmy" +
                 "</Name></RespectBrowserAcceptHeaderController.Employee>";
-            var expectedResponseData = @"{""Id"":35,""Name"":""Jimmy""}";
+            var expectedResponseData = @"{""id"":35,""name"":""Jimmy""}";
             var request = RequestWithAccept("http://localhost/RespectBrowserAcceptHeader/CreateEmployee", acceptHeader);
             request.Content = new StringContent(requestData, Encoding.UTF8, "application/xml");
             request.Method = HttpMethod.Post;

test/Microsoft.AspNetCore.Mvc.FunctionalTests/WebApiCompatShimActionResultTest.cs

@@ -74,7 +74,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.Ambiguous, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
         }
 
         [Fact]
@@ -86,7 +86,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.Created, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
             Assert.Equal("5", response.Headers.Location.OriginalString);
         }
 
@@ -99,7 +99,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.Created, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
             Assert.Equal("/api/Blog/ActionResult/GetUser/5", response.Headers.Location.OriginalString);
         }
 
@@ -112,7 +112,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.Created, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
             Assert.Equal("http://localhost/api/Blog/ActionResult/5", response.Headers.Location.OriginalString);
         }
 
@@ -125,7 +125,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.Created, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
             Assert.Equal("/api/Blog/ActionResult/GetUser/5", response.Headers.Location.OriginalString);
         }
 
@@ -138,7 +138,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.Created, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
             Assert.Equal("http://localhost/api/Blog/ActionResult/GetUser/5", response.Headers.Location.OriginalString);
         }
 
@@ -173,7 +173,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
         }
 
         [Fact]
@@ -182,7 +182,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Arrange
             var expected =
                 "{" + Environment.NewLine +
-                "  \"Name\": \"Test User\"" + Environment.NewLine +
+                "  \"name\": \"Test User\"" + Environment.NewLine +
                 "}";
 
             // Act
@@ -200,7 +200,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Arrange
             var expected =
                 "{" + Environment.NewLine +
-                "  \"Name\": \"Test User\"" + Environment.NewLine +
+                "  \"name\": \"Test User\"" + Environment.NewLine +
                 "}";
 
             // Act
@@ -242,7 +242,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
-            Assert.Equal("{\"Name\":\"Test User\"}", content);
+            Assert.Equal("{\"name\":\"Test User\"}", content);
         }
 
         [Fact]

test/Microsoft.AspNetCore.Mvc.FunctionalTests/WebApiCompatShimParameterBindingTest.cs

@@ -150,7 +150,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
-            Assert.Equal("{\"Id\":5,\"Name\":\"Test Employee\"}", content);
+            Assert.Equal("{\"id\":5,\"name\":\"Test Employee\"}", content);
         }
 
         [Fact]
@@ -170,7 +170,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
-            Assert.Equal("{\"Id\":5,\"Name\":\"Test Employee\"}", content);
+            Assert.Equal("{\"id\":5,\"name\":\"Test Employee\"}", content);
         }
 
         // name is read from the url - and the rest from the body (formatters)
@@ -193,7 +193,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
-            Assert.Equal("{\"Id\":5,\"Name\":\"Name_Override\"}", content);
+            Assert.Equal("{\"id\":5,\"name\":\"Name_Override\"}", content);
         }
     }
 }

test/WebSites/BasicWebSite/Controllers/HomeController.cs

@@ -5,7 +5,7 @@ using System.Threading.Tasks;
 using BasicWebSite.Models;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
-using Microsoft.AspNetCore.Mvc.Controllers;
+using Newtonsoft.Json.Serialization;
 
 namespace BasicWebSite.Controllers
 {
@@ -65,20 +65,21 @@ namespace BasicWebSite.Controllers
         {
             Person person = new Person
             {
-                Id = 9000,
+                id = 9000,
-                Name = "John <b>Smith</b>"
+                FullName = "John <b>Smith</b>"
             };
 
             return View(person);
         }
 
-        public IActionResult JsonHelperWithSettingsInView()
+        public IActionResult JsonHelperWithSettingsInView(bool snakeCase)
         {
             Person person = new Person
             {
-                Id = 9000,
+                id = 9000,
-                Name = "John <b>Smith</b>"
+                FullName = "John <b>Smith</b>"
             };
+            ViewData["naming"] = snakeCase ? (NamingStrategy)new SnakeCaseNamingStrategy() : new DefaultNamingStrategy();
 
             return View(person);
         }

test/WebSites/BasicWebSite/Models/Person.cs

@@ -5,8 +5,8 @@ namespace BasicWebSite.Models
 {
     public class Person
     {
-        public int Id { get; set; }
+        public int id { get; set; }
 
-        public string Name { get; set; }
+        public string FullName { get; set; }
     }
 }

test/WebSites/BasicWebSite/Views/Home/JsonHelperWithSettingsInView.cshtml

@@ -3,7 +3,10 @@
 @using Newtonsoft.Json.Serialization
 @{
     var settings = JsonSerializerSettingsProvider.CreateSerializerSettings();
-    settings.ContractResolver = new CamelCasePropertyNamesContractResolver();
+    settings.ContractResolver = new DefaultContractResolver
+    {
+        NamingStrategy = (NamingStrategy)(ViewData["naming"]),
+    };
 }
 <script type="text/javascript">
     var json = @Json.Serialize(Model, settings);