[AppConfig] Fix disposed stream access (Azure#38531)

The focus of these changes is to fix a bug where the content stream returned
by the protocol method has been disposed and the serializer attempts to access
it.  Shifting to accessing the `BinaryData` content directly for deserialization.

Author: jsquire

sdk/appconfiguration/Azure.Data.AppConfiguration/CHANGELOG.md

@@ -4,12 +4,16 @@
 
 ### Bugs Fixed
 
-- `FeatureFlagConfigurationSetting` and `SecretReferenceConfigurationSetting` will now retain custom attributes in the setting value.  Previously, only attributes that were defined in the associated JSON schema were allowed and unknown attributes were discarded.  
+- `FeatureFlagConfigurationSetting` and `SecretReferenceConfigurationSetting` will now retain custom attributes in the setting value.  Previously, only attributes that were defined in the associated JSON schema were allowed and unknown attributes were discarded.
 
 - Added the ability to create `FeatureFlagConfigurationSetting` and `SecretReferenceConfigurationSetting` instances with an ETag, matching `ConfigurationSetting`.  This allows all setting types to use the [GetConfigurationSettingAsync](https://learn.microsoft.com/dotnet/api/azure.data.appconfiguration.configurationclient.getconfigurationsettingasync?view=azure-dotnet#azure-data-appconfiguration-configurationclient-getconfigurationsettingasync(azure-data-appconfiguration-configurationsetting-system-boolean-system-threading-cancellationtoken)) overload that accepts `onlyIfUnchanged.`  Previously, this was not possible for specialized settings types.
 
 - Added the ability to create `FeatureFlagConfigurationSetting` and `SecretReferenceConfigurationSetting` instances for testing purposes using the `ConfigurationModelFactory`. It was previously not possible to populate service-owned fields when testing.
 
+- Marked a constructor overload of `ConfigurationSetting` that was intended for testing purposes as non-visible, as the `ConfigurationModelFactory` should instead be used.
+
+- Fixed a bug where a disposed content stream was used to attempt deserialization in some scenarios, such as using a custom `HttpMessageHandler` that returns `StringContent`.
+
 ## 1.3.0-beta.2 (2023-07-11)
 
 ### Features Added
@@ -77,7 +81,7 @@
 
 #### New Features
 
-- Added `SecretReferenceConfigurationSetting` type to represent a configuration setting that references a KeyVault Secret. 
+- Added `SecretReferenceConfigurationSetting` type to represent a configuration setting that references a KeyVault Secret.
 - Added `FeatureFlagConfigurationSetting` type to represent a configuration setting that controls a feature flag.
 - Added `AddSyncToken` to `ConfigurationClient` to be able to provide external synchronization tokens.
 
@@ -89,7 +93,7 @@
 
 - Update the tag list for the AzConfig package
 
-## 1.0.0 
+## 1.0.0
 
 ### Breaking changes
 
@@ -99,11 +103,11 @@
 
 - Fixed multiple issues with connection string parsing in `ConfigurationClient`.
 
-## 1.0.0-preview.6 
+## 1.0.0-preview.6
 
 - Bugfixes: [#8920](https://github.com/Azure/azure-sdk-for-net/issues/8920)
 
-## 1.0.0-preview.5 
+## 1.0.0-preview.5
 
 ### Breaking changes
 
@@ -116,7 +120,7 @@
 - Added new overload for the method `ConfigurationClient.GetRevisions` that accepts key and optional label.
 - Added new overload for the method `ConfigurationClient.GetConfigurationSetting` that accepts `ConfigurationSetting` and its datetime stamp.
 
-## 1.0.0-preview.4 
+## 1.0.0-preview.4
 
 ### Breaking changes
 
@@ -135,11 +139,11 @@
 - Made `ConfigurationSetting` serializable by `System.Text.Json` serializers.
 - Updated documentation and samples.
 
-## 1.0.0-preview.3 
+## 1.0.0-preview.3
 
 - Fixed an issue where special characters were escaped incorrectly.
 
-## 1.0.0-preview.2 
+## 1.0.0-preview.2
 
 - Enabled conditional requests.
 - Added support for setting `x-ms-client-request-id`, `x-ms-correlation-request-id`, and `correlation-context` headers.

sdk/appconfiguration/Azure.Data.AppConfiguration/src/ConfigurationClient_private.cs

@@ -2,10 +2,8 @@
 // Licensed under the MIT License.
 
 using System;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Azure.Core;
@@ -21,13 +19,13 @@ public partial class ConfigurationClient
 
         private static async Task<Response<ConfigurationSetting>> CreateResponseAsync(Response response, CancellationToken cancellation)
         {
-            ConfigurationSetting result = await ConfigurationServiceSerializer.DeserializeSettingAsync(response.ContentStream, cancellation).ConfigureAwait(false);
+            ConfigurationSetting result = await ConfigurationServiceSerializer.DeserializeSettingAsync(response.Content, cancellation).ConfigureAwait(false);
             return Response.FromValue(result, response);
         }
 
         private static Response<ConfigurationSetting> CreateResponse(Response response)
         {
-            return Response.FromValue(ConfigurationServiceSerializer.DeserializeSetting(response.ContentStream), response);
+            return Response.FromValue(ConfigurationServiceSerializer.DeserializeSetting(response.Content), response);
         }
 
         private static Response<ConfigurationSetting> CreateResourceModifiedResponse(Response response)

sdk/appconfiguration/Azure.Data.AppConfiguration/src/Models/ConfigurationServiceSerializer.cs

@@ -169,18 +169,18 @@ private static void ReadPropertyValue(ConfigurationSetting setting, JsonProperty
             }
         }
 
-        public static async Task<ConfigurationSetting> DeserializeSettingAsync(Stream content, CancellationToken cancellation)
+        public static async Task<ConfigurationSetting> DeserializeSettingAsync(BinaryData content, CancellationToken cancellation)
         {
-            using (JsonDocument json = await JsonDocument.ParseAsync(content, default, cancellation).ConfigureAwait(false))
+            using (JsonDocument json = await JsonDocument.ParseAsync(content.ToStream(), default, cancellation).ConfigureAwait(false))
             {
                 JsonElement root = json.RootElement;
                 return ReadSetting(root);
             }
         }
 
-        public static ConfigurationSetting DeserializeSetting(Stream content)
+        public static ConfigurationSetting DeserializeSetting(BinaryData content)
         {
-            using JsonDocument json = JsonDocument.Parse(content, default);
+            using JsonDocument json = JsonDocument.Parse(content.ToMemory(), default);
             JsonElement root = json.RootElement;
             return ReadSetting(root);
         }

sdk/appconfiguration/Azure.Data.AppConfiguration/tests/ConfigurationMockTests.cs

@@ -7,6 +7,8 @@
 using System.Globalization;
 using System.IO;
 using System.Linq;
+using System.Net;
+using System.Net.Http;
 using System.Text;
 using System.Text.Json;
 using System.Text.RegularExpressions;
@@ -870,6 +872,33 @@ public async Task VerifyNullClientFilter()
             Assert.IsEmpty(feature.ClientFilters);
         }
 
+        [Test]
+        public async Task SupportsCustomTransportUse()
+        {
+            var expectedKey = "abc";
+            var expectedValue = "ghi";
+            var expectedLabel = "def";
+            var expectedContent = @$"{{""key"":""{expectedKey}"",""label"":""{expectedLabel}"",""value"":""{expectedValue}""}}";
+
+            var client = new ConfigurationClient(
+                s_connectionString,
+                new ConfigurationClientOptions
+                {
+                    Transport = new HttpClientTransport(new EchoHttpMessageHandler(expectedContent))
+                }
+            );
+
+            var result = await client.GetConfigurationSettingAsync("doesnt-matter");
+            Assert.AreEqual(expectedKey, result.Value.Key);
+            Assert.AreEqual(expectedValue, result.Value.Value);
+            Assert.AreEqual(expectedLabel, result.Value.Label);
+
+            var result2 = await client.SetConfigurationSettingAsync("whatever", "somevalue");
+            Assert.AreEqual(expectedKey, result.Value.Key);
+            Assert.AreEqual(expectedValue, result.Value.Value);
+            Assert.AreEqual(expectedLabel, result.Value.Label);
+        }
+
         private void AssertContent(byte[] expected, MockRequest request, bool compareAsString = true)
         {
             using (var stream = new MemoryStream())
@@ -961,5 +990,24 @@ private void SerializeBatch(ref Utf8JsonWriter json, (ConfigurationSetting[] Set
             json.WriteEndArray();
             json.WriteEndObject();
         }
+
+        private class EchoHttpMessageHandler : HttpMessageHandler
+        {
+            private readonly string _expectedContent;
+
+            public EchoHttpMessageHandler(string expectedJsonContent)
+            {
+                _expectedContent = expectedJsonContent;
+            }
+
+            protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+            {
+                return Task.FromResult(new HttpResponseMessage()
+                {
+                    StatusCode = HttpStatusCode.OK,
+                    Content = new StringContent(_expectedContent, Encoding.UTF8, "application/json")
+                });
+            }
+        }
     }
 }