Sro auth examples (#2442)

* v2.9.0

* Add examples for SR OAuth

Author: Claimundefine

examples/SchemaRegistryOAuth/Program.cs

@@ -0,0 +1,117 @@
+// Copyright 2025 Confluent Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Refer to LICENSE for more information.
+
+using Confluent.SchemaRegistry;
+using System.Net.Http.Headers;
+/// <summary>
+///     An example showing schema registry authentication 
+///     with an OAUTHBEARER token implementation.
+/// </summary>
+namespace Confluent.Kafka.Examples.SchemaRegistryOAuth
+{
+
+    public class Program
+    {   
+
+        private class ExampleBearerAuthProvider : IAuthenticationBearerHeaderValueProvider
+        {
+            private string token;
+            private string logicalCluster;
+            private string identityPool;
+
+
+            public ExampleBearerAuthProvider(string token, string logicalCluster, string identityPool)
+            {
+                this.token = token;
+                this.logicalCluster = logicalCluster;
+                this.identityPool = identityPool;
+            }
+
+            public string GetBearerToken() => token;
+            public AuthenticationHeaderValue GetAuthenticationHeader() => new AuthenticationHeaderValue("Bearer", token);
+            public string GetLogicalCluster() => logicalCluster;
+            public string GetIdentityPool() => identityPool;
+            public bool NeedsInitOrRefresh() => false;
+            public Task InitOrRefreshAsync() => Task.CompletedTask;
+        }
+
+        public static async Task Main(string[] args)
+        {
+            if (args.Length != 9)
+            {
+                Console.WriteLine("Usage: .. schemaRegistryUrl clientId clientSecret scope tokenEndpoint logicalCluster identityPool token");
+                return;
+            }
+            string schemaRegistryUrl = args[1];
+            string clientId = args[2];
+            string clientSecret = args[3];
+            string scope = args[4];
+            string tokenEndpoint = args[5];
+            string logicalCluster = args[6];
+            string identityPool = args[7];
+            string token = args[8];
+
+            //using BearerAuthCredentialsSource.OAuthBearer
+            var clientCredentialsSchemaRegistryConfig = new SchemaRegistryConfig
+            {   
+                Url = schemaRegistryUrl,
+                BearerAuthCredentialsSource = BearerAuthCredentialsSource.OAuthBearer,
+                BearerAuthClientId = clientId,
+                BearerAuthClientSecret = clientSecret,
+                BearerAuthScope = scope,
+                BearerAuthTokenEndpointUrl = tokenEndpoint,
+                BearerAuthLogicalCluster = logicalCluster,
+                BearerAuthIdentityPoolId = identityPool
+            };
+
+            using (var schemaRegistry = new CachedSchemaRegistryClient(clientCredentialsSchemaRegistryConfig))
+            {
+                var subjects = await schemaRegistry.GetAllSubjectsAsync();
+                Console.WriteLine(string.Join(", ", subjects));
+            }
+
+            //using BearerAuthCredentialsSource.StaticToken
+            var staticSchemaRegistryConfig = new SchemaRegistryConfig
+            {   
+                Url = schemaRegistryUrl,
+                BearerAuthCredentialsSource = BearerAuthCredentialsSource.StaticToken,
+                BearerAuthToken = token,
+                BearerAuthLogicalCluster = logicalCluster,
+                BearerAuthIdentityPoolId = identityPool
+            };
+
+            using (var schemaRegistry = new CachedSchemaRegistryClient(staticSchemaRegistryConfig))
+            {
+                var subjects = await schemaRegistry.GetAllSubjectsAsync();
+                Console.WriteLine(string.Join(", ", subjects));
+            }
+
+            //Using BearerAuthCredentialsSource.Custom
+            var customSchemaRegistryConfig = new SchemaRegistryConfig
+            {   
+                Url = schemaRegistryUrl,
+                BearerAuthCredentialsSource = BearerAuthCredentialsSource.Custom
+            };
+
+            var customProvider = new ExampleBearerAuthProvider(token, logicalCluster, identityPool);
+            using (var schemaRegistry = new CachedSchemaRegistryClient(customSchemaRegistryConfig, customProvider))
+            {
+                var subjects = await schemaRegistry.GetAllSubjectsAsync();
+                Console.WriteLine(string.Join(", ", subjects));
+            }
+        }
+    }
+}

examples/SchemaRegistryOAuth/SchemaRegistryOAuth.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+    <ItemGroup>
+      <!-- nuget package reference: <PackageReference Include="Confluent.SchemaRegistry" Version="2.9.0" /> -->
+      <ProjectReference Include="..\..\src\Confluent.SchemaRegistry\Confluent.SchemaRegistry.csproj" />
+    </ItemGroup>
+
+</Project>