introduce the abstraction for tokencredential type and keycredential …

…type (microsoft#5231)

Fixes microsoft#5235
Fixes microsoft#4410

The ClientProviderTests class contains both general client provider
features (such as service operations, query parameters, api-versions)
and auth specific features.
My PR is trying to separate them - therefore some test cases are moved
to a new class.

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Primitives/ScmKnownParameters.cs

@@ -30,8 +30,6 @@ internal static class ScmKnownParameters
         public static readonly ParameterProvider Data = new("data", FormattableStringHelpers.Empty, typeof(BinaryData));
         public static ParameterProvider ClientOptions(CSharpType clientOptionsType)
             => new("options", $"The options for configuring the client.", clientOptionsType.WithNullable(true), initializationValue: New.Instance(clientOptionsType.WithNullable(true)));
-        public static readonly ParameterProvider KeyAuth = new("keyCredential", $"The token credential to copy", ClientModelPlugin.Instance.TypeFactory.KeyCredentialType);
-        public static readonly ParameterProvider MatchConditionsParameter = new("matchConditions", $"The content to send as the request conditions of the request.", ClientModelPlugin.Instance.TypeFactory.MatchConditionsType, DefaultOf(ClientModelPlugin.Instance.TypeFactory.MatchConditionsType));
         public static readonly ParameterProvider OptionalRequestOptions = new(
             ClientModelPlugin.Instance.TypeFactory.HttpRequestOptionsApi.ParameterName,
             $"The request options, which can override default behaviors of the client pipeline on a per-call basis.",

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Providers/Abstractions/ClientPipelineApi.cs

@@ -14,6 +14,8 @@ public abstract record ClientPipelineApi : ScopedApi, IClientPipelineApi
         public abstract CSharpType ClientPipelineType { get; }
         public abstract CSharpType ClientPipelineOptionsType { get; }
         public abstract CSharpType PipelinePolicyType { get; }
+        public abstract CSharpType? KeyCredentialType { get; }
+        public abstract CSharpType? TokenCredentialType { get; }
 
         protected ClientPipelineApi(Type type, ValueExpression original) : base(type, original)
         {
@@ -26,7 +28,8 @@ protected ClientPipelineApi(Type type, ValueExpression original) : base(type, or
 
         public abstract ValueExpression Create(ValueExpression options, ValueExpression perRetryPolicies);
 
-        public abstract ValueExpression AuthorizationPolicy(params ValueExpression[] arguments);
+        public abstract ValueExpression KeyAuthorizationPolicy(ValueExpression credential, ValueExpression headerName, ValueExpression? keyPrefix = null);
+        public abstract ValueExpression TokenAuthorizationPolicy(ValueExpression credential, ValueExpression scopes);
         public abstract ClientPipelineApi FromExpression(ValueExpression expression);
         public abstract ClientPipelineApi ToExpression();
     }

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Providers/Abstractions/IClientPipelineApi.cs

@@ -10,5 +10,8 @@ public interface IClientPipelineApi : IExpressionApi<ClientPipelineApi>
         CSharpType ClientPipelineType { get; }
         CSharpType ClientPipelineOptionsType { get; }
         CSharpType PipelinePolicyType { get; }
+
+        CSharpType? KeyCredentialType { get; }
+        CSharpType? TokenCredentialType { get; }
     }
 }

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Providers/ClientPipelineProvider.cs

@@ -1,11 +1,13 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using System;
+using System.ClientModel;
 using System.ClientModel.Primitives;
 using Microsoft.Generator.CSharp.Expressions;
 using Microsoft.Generator.CSharp.Primitives;
-using Microsoft.Generator.CSharp.Statements;
 using Microsoft.Generator.CSharp.Snippets;
+using Microsoft.Generator.CSharp.Statements;
 using static Microsoft.Generator.CSharp.Snippets.Snippet;
 
 namespace Microsoft.Generator.CSharp.ClientModel.Providers
@@ -25,6 +27,10 @@ public ClientPipelineProvider(ValueExpression original) : base(typeof(ClientPipe
 
         public override CSharpType PipelinePolicyType => typeof(PipelinePolicy);
 
+        public override CSharpType KeyCredentialType => typeof(ApiKeyCredential);
+
+        public override CSharpType? TokenCredentialType => null; // Scm library does not support token credentials yet.
+
         public override ValueExpression Create(ValueExpression options, ValueExpression perRetryPolicies)
             => Static<ClientPipeline>().Invoke(nameof(ClientPipeline.Create), [options, New.Array(ClientModelPlugin.Instance.TypeFactory.ClientPipelineApi.PipelinePolicyType), perRetryPolicies, New.Array(ClientModelPlugin.Instance.TypeFactory.ClientPipelineApi.PipelinePolicyType)]).As<ClientPipeline>();
 
@@ -34,8 +40,18 @@ public override ValueExpression CreateMessage(HttpRequestOptionsApi requestOptio
         public override ClientPipelineApi FromExpression(ValueExpression expression)
             => new ClientPipelineProvider(expression);
 
-        public override ValueExpression AuthorizationPolicy(params ValueExpression[] arguments)
-            => Static<ApiKeyAuthenticationPolicy>().Invoke(nameof(ApiKeyAuthenticationPolicy.CreateHeaderApiKeyPolicy), arguments).As<ApiKeyAuthenticationPolicy>();
+        public override ValueExpression KeyAuthorizationPolicy(ValueExpression credential, ValueExpression headerName, ValueExpression? keyPrefix = null)
+        {
+            ValueExpression[] arguments = keyPrefix == null ? [credential, headerName] : [credential, headerName, keyPrefix];
+            return Static<ApiKeyAuthenticationPolicy>().Invoke(nameof(ApiKeyAuthenticationPolicy.CreateHeaderApiKeyPolicy), arguments).As<ApiKeyAuthenticationPolicy>();
+        }
+
+        public override ValueExpression TokenAuthorizationPolicy(ValueExpression credential, ValueExpression scopes)
+        {
+            // Scm library does not support token credentials yet. The throw here is intentional.
+            // For a plugin that supports token credentials, they could override this implementation as well as the above TokenCredentialType property.
+            throw new NotImplementedException();
+        }
 
         public override ClientPipelineApi ToExpression() => this;