Azure App Configuration - Feature Flag Resource

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

@@ -707,7 +707,7 @@ public virtual AsyncPageable<ConfigurationSetting> GetConfigurationSettingsAsync
 
             var pageableImplementation = GetConfigurationSettingsPageableImplementation(selector, cancellationToken);
 
-            return new AsyncConditionalPageable(pageableImplementation);
+            return new AsyncConditionalPageable<ConfigurationSetting>(pageableImplementation);
         }
 
         /// <summary>
@@ -721,10 +721,10 @@ public virtual Pageable<ConfigurationSetting> GetConfigurationSettings(SettingSe
 
             var pageableImplementation = GetConfigurationSettingsPageableImplementation(selector, cancellationToken);
 
-            return new ConditionalPageable(pageableImplementation);
+            return new ConditionalPageable<ConfigurationSetting>(pageableImplementation);
         }
 
-        private ConditionalPageableImplementation GetConfigurationSettingsPageableImplementation(SettingSelector selector, CancellationToken cancellationToken)
+        private ConditionalPageableImplementation<ConfigurationSetting> GetConfigurationSettingsPageableImplementation(SettingSelector selector, CancellationToken cancellationToken)
         {
             var key = selector.KeyFilter;
             var label = selector.LabelFilter;
@@ -747,7 +747,7 @@ HttpMessage NextPageRequest(MatchConditions conditions, int? pageSizeHint, strin
                 return CreateNextGetConfigurationSettingsRequest(nextLink, key, label, _syncToken, null, dateTime, fieldsString, null, conditions, tags, context);
             }
 
-            return new ConditionalPageableImplementation(FirstPageRequest, NextPageRequest, ParseGetConfigurationSettingsResponse, Pipeline, ClientDiagnostics, "ConfigurationClient.GetConfigurationSettings", context);
+            return new ConditionalPageableImplementation<ConfigurationSetting>(FirstPageRequest, NextPageRequest, ParseGetConfigurationSettingsResponse, Pipeline, ClientDiagnostics, "ConfigurationClient.GetConfigurationSettings", context);
         }
 
         /// <summary>

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

@@ -34,7 +34,7 @@ public static IAsyncEnumerable<Page<ConfigurationSetting>> AsPages(this AsyncPag
         {
             Argument.AssertNotNull(conditions, nameof(conditions));
 
-            var conditionalPageable = pageable as AsyncConditionalPageable;
+            var conditionalPageable = pageable as AsyncConditionalPageable<ConfigurationSetting>;
 
             if (conditionalPageable is null)
             {
@@ -66,7 +66,7 @@ public static IEnumerable<Page<ConfigurationSetting>> AsPages(this Pageable<Conf
         {
             Argument.AssertNotNull(conditions, nameof(conditions));
 
-            var conditionalPageable = pageable as ConditionalPageable;
+            var conditionalPageable = pageable as ConditionalPageable<ConfigurationSetting>;
 
             if (conditionalPageable is null)
             {

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

@@ -0,0 +1,89 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using Azure.Core;
+
+namespace Azure.Data.AppConfiguration
+{
+    /// <summary>
+    /// Options that allow users to configure the requests sent to the App Configuration feature flags service.
+    /// </summary>
+    [CodeGenSuppress("FeatureFlagClientOptions", typeof(ServiceVersion))]
+    public partial class FeatureFlagClientOptions : ClientOptions
+    {
+        private const ServiceVersion LatestVersion = ServiceVersion.V2023_11_01;
+        private const string AzConfigUsGovCloudHostName = "azconfig.azure.us";
+        private const string AzConfigChinaCloudHostName = "azconfig.azure.cn";
+        private const string AppConfigUsGovCloudHostName = "appconfig.azure.us";
+        private const string AppConfigChinaCloudHostName = "appconfig.azure.cn";
+
+        /// <summary>
+        /// The versions of the App Configuration service supported by this client library.
+        /// </summary>
+        public enum ServiceVersion
+        {
+#pragma warning disable CA1707 // Identifiers should not contain underscores
+            /// <summary>
+            /// Version 1.0.
+            /// </summary>
+            V1_0 = 0,
+
+            /// <summary>
+            /// Version 2023-10-01.
+            /// </summary>
+            V2023_10_01 = 1,
+
+            /// <summary>
+            /// Version 2023-11-01.
+            /// </summary>
+            V2023_11_01 = 2
+        }
+
+        /// <summary>
+        /// Gets or sets the Audience to use for authentication with Microsoft Entra. The audience is not considered when using a shared key.
+        /// </summary>
+        public AppConfigurationAudience? Audience { get; set; }
+
+        internal string Version { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FeatureFlagClientOptions"/>
+        /// class.
+        /// </summary>
+        /// <param name="version">
+        /// The <see cref="ServiceVersion"/> of the service API used when
+        /// making requests.
+        /// </param>
+        public FeatureFlagClientOptions(ServiceVersion version = LatestVersion)
+        {
+            Version = version switch
+            {
+                ServiceVersion.V1_0 => "1.0",
+                ServiceVersion.V2023_10_01 => "2023-10-01",
+                ServiceVersion.V2023_11_01 => "2023-11-01",
+
+                _ => throw new NotSupportedException()
+            };
+            this.ConfigureLogging();
+        }
+
+        internal string GetDefaultScope(Uri uri)
+        {
+            if (string.IsNullOrEmpty(Audience?.ToString()))
+            {
+                string host = uri.GetComponents(UriComponents.Host, UriFormat.SafeUnescaped);
+                return host switch
+                {
+                    _ when host.EndsWith(AzConfigUsGovCloudHostName, StringComparison.InvariantCultureIgnoreCase) || host.EndsWith(AppConfigUsGovCloudHostName, StringComparison.InvariantCultureIgnoreCase)
+                        => $"{AppConfigurationAudience.AzureGovernment}/.default",
+                    _ when host.EndsWith(AzConfigChinaCloudHostName, StringComparison.InvariantCultureIgnoreCase) || host.EndsWith(AppConfigChinaCloudHostName, StringComparison.InvariantCultureIgnoreCase)
+                        => $"{AppConfigurationAudience.AzureChina}/.default",
+                    _ => $"{AppConfigurationAudience.AzurePublicCloud}/.default"
+                };
+            }
+
+            return $"{Audience}/.default";
+        }
+    }
+}

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

@@ -0,0 +1,136 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.ClientModel.Primitives;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Azure.Core;
+
+namespace Azure.Data.AppConfiguration
+{
+    public partial class FeatureFlagClient
+    {
+        private const string AcceptDateTimeFormat = "R";
+
+        private static Response<FeatureFlag> CreateResponse(Response response)
+        {
+            var options = ModelReaderWriterOptions.Json;
+
+            FeatureFlag result = FeatureFlag.DeserializeFeatureFlag(response.Content.ToObjectFromJson<JsonElement>(), options);
+            return Response.FromValue(result, response);
+        }
+
+        private static Response<FeatureFlag> CreateResourceModifiedResponse(Response response)
+        {
+            return new NoBodyResponse<FeatureFlag>(response);
+        }
+
+        private static void ParseConnectionString(string connectionString, out Uri uri, out string credential, out byte[] secret)
+        {
+            Debug.Assert(connectionString != null); // callers check this
+
+            var parsed = ConnectionString.Parse(connectionString);
+
+            uri = new Uri(parsed.GetRequired("Endpoint"));
+            credential = parsed.GetRequired("Id");
+            try
+            {
+                secret = Convert.FromBase64String(parsed.GetRequired("Secret"));
+            }
+            catch (FormatException)
+            {
+                throw new InvalidOperationException("Specified Secret value isn't a valid base64 string");
+            }
+        }
+
+        private HttpMessage CreateNextGetFeatureFlagsRequest(string nextLink, string syncToken, string acceptDatetime, MatchConditions matchConditions, RequestContext context)
+        {
+            HttpMessage message = Pipeline.CreateMessage(context, PipelineMessageClassifier200);
+            Request request = message.Request;
+            request.Method = RequestMethod.Get;
+            RawRequestUriBuilder uri = new RawRequestUriBuilder();
+            uri.Reset(_endpoint);
+            uri.AppendRawNextLink(nextLink, false);
+            request.Uri = uri;
+            if (syncToken != null)
+            {
+                request.Headers.SetValue("Sync-Token", syncToken);
+            }
+            if (acceptDatetime != null)
+            {
+                request.Headers.SetValue("Accept-Datetime", acceptDatetime);
+            }
+            if (matchConditions != null)
+            {
+                request.Headers.Add(matchConditions);
+            }
+            request.Headers.SetValue("Accept", "application/problem+json, application/vnd.microsoft.appconfig.kvset+json");
+            return message;
+        }
+
+        private HttpMessage CreateNextGetRevisionsRequest(string nextLink, string syncToken, string acceptDatetime, RequestContext context)
+        {
+            HttpMessage message = Pipeline.CreateMessage(context, PipelineMessageClassifier200);
+            Request request = message.Request;
+            request.Method = RequestMethod.Get;
+            RawRequestUriBuilder uri = new RawRequestUriBuilder();
+            uri.Reset(_endpoint);
+            uri.AppendRawNextLink(nextLink, false);
+            if (syncToken != null)
+            {
+                request.Headers.SetValue("Sync-Token", syncToken);
+            }
+            if (acceptDatetime != null)
+            {
+                request.Headers.SetValue("Accept-Datetime", acceptDatetime);
+            }
+            request.Headers.SetValue("Accept", "application/problem+json, application/vnd.microsoft.appconfig.kvset+json");
+            return message;
+        }
+
+        /// <summary>
+        /// Parses the response of a <see cref="GetFeatureFlags(FeatureFlagSelector, CancellationToken)"/> request.
+        /// The "@nextLink" JSON property is not reliable since the service does not return a response body for 304
+        /// responses. This method also attempts to extract the next link address from the "Link" header.
+        /// </summary>
+        private (List<FeatureFlag> Values, string NextLink) ParseGetGetFeatureFlagsResponse(Response response)
+        {
+            var values = new List<FeatureFlag>();
+            string nextLink = null;
+
+            if (response.Status == 200)
+            {
+                var document = response.ContentStream != null ? JsonDocument.Parse(response.ContentStream) : JsonDocument.Parse(response.Content);
+
+                if (document.RootElement.TryGetProperty("items", out var itemsValue))
+                {
+                    foreach (var jsonItem in itemsValue.EnumerateArray())
+                    {
+                        FeatureFlag setting = FeatureFlag.DeserializeFeatureFlag(jsonItem, default);
+                        values.Add(setting);
+                    }
+                }
+
+                if (document.RootElement.TryGetProperty("@nextLink", out var nextLinkValue))
+                {
+                    nextLink = nextLinkValue.GetString();
+                }
+            }
+
+            // The "Link" header is formatted as:
+            // <nextLink>; rel="next"
+            if (nextLink == null && response.Headers.TryGetValue("Link", out string linkHeader))
+            {
+                int nextLinkEndIndex = linkHeader.IndexOf('>');
+                nextLink = linkHeader.Substring(1, nextLinkEndIndex - 1);
+            }
+
+            return (values, nextLink);
+        }
+    }
+}