Add Zendesk to the list of supported providers

src/OpenIddict.Client.SystemNetHttp/OpenIddictClientSystemNetHttpHandlers.Userinfo.cs

@@ -76,7 +76,7 @@ public static partial class OpenIddictClientSystemNetHttpHandlers
                 // Attach the authorization header containing the access token to the HTTP request.
                 request.Headers.Authorization = new AuthenticationHeaderValue(Schemes.Bearer, context.Request.AccessToken);
 
-                // Remove the access from the request payload to ensure it's not sent twice.
+                // Remove the access token from the request payload to ensure it's not sent twice.
                 context.Request.AccessToken = null;
 
                 return default;

src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationHandlers.Revocation.cs

@@ -6,6 +6,7 @@
 
 using System.Collections.Immutable;
 using System.Net.Http;
+using System.Net.Http.Headers;
 using static OpenIddict.Client.SystemNetHttp.OpenIddictClientSystemNetHttpHandlerFilters;
 using static OpenIddict.Client.SystemNetHttp.OpenIddictClientSystemNetHttpHandlers;
 using static OpenIddict.Client.WebIntegration.OpenIddictClientWebIntegrationConstants;
@@ -17,12 +18,102 @@ public static partial class OpenIddictClientWebIntegrationHandlers
     public static class Revocation
     {
         public static ImmutableArray<OpenIddictClientHandlerDescriptor> DefaultHandlers { get; } = ImmutableArray.Create([
+            /*
+             * Revocation request preparation:
+             */
+            OverrideHttpMethod.Descriptor,
+            AttachBearerAccessToken.Descriptor,
+
             /*
              * Revocation response extraction:
              */
             NormalizeContentType.Descriptor
         ]);
 
+        /// <summary>
+        /// Contains the logic responsible for overriding the HTTP method for the providers that require it.
+        /// </summary>
+        public sealed class OverrideHttpMethod : IOpenIddictClientHandler<PrepareRevocationRequestContext>
+        {
+            /// <summary>
+            /// Gets the default descriptor definition assigned to this handler.
+            /// </summary>
+            public static OpenIddictClientHandlerDescriptor Descriptor { get; }
+                = OpenIddictClientHandlerDescriptor.CreateBuilder<PrepareRevocationRequestContext>()
+                    .AddFilter<RequireHttpUri>()
+                    .UseSingletonHandler<OverrideHttpMethod>()
+                    .SetOrder(PreparePostHttpRequest<PrepareRevocationRequestContext>.Descriptor.Order + 250)
+                    .SetType(OpenIddictClientHandlerType.BuiltIn)
+                    .Build();
+
+            /// <inheritdoc/>
+            public ValueTask HandleAsync(PrepareRevocationRequestContext context)
+            {
+                if (context is null)
+                {
+                    throw new ArgumentNullException(nameof(context));
+                }
+
+                // This handler only applies to System.Net.Http requests. If the HTTP request cannot be resolved,
+                // this may indicate that the request was incorrectly processed by another client stack.
+                var request = context.Transaction.GetHttpRequestMessage() ??
+                    throw new InvalidOperationException(SR.GetResourceString(SR.ID0173));
+
+                request.Method = context.Registration.ProviderType switch
+                {
+
+                    ProviderTypes.Zendesk => HttpMethod.Delete,
+
+                    _ => request.Method
+                };
+
+                return default;
+            }
+        }
+
+        /// <summary>
+        /// Contains the logic responsible for attaching the token to revoke
+        /// to the HTTP Authorization header for the providers that require it.
+        /// </summary>
+        public sealed class AttachBearerAccessToken : IOpenIddictClientHandler<PrepareRevocationRequestContext>
+        {
+            /// <summary>
+            /// Gets the default descriptor definition assigned to this handler.
+            /// </summary>
+            public static OpenIddictClientHandlerDescriptor Descriptor { get; }
+                = OpenIddictClientHandlerDescriptor.CreateBuilder<PrepareRevocationRequestContext>()
+                    .AddFilter<RequireHttpUri>()
+                    .UseSingletonHandler<AttachBearerAccessToken>()
+                    .SetOrder(AttachHttpParameters<PrepareRevocationRequestContext>.Descriptor.Order - 500)
+                    .SetType(OpenIddictClientHandlerType.BuiltIn)
+                    .Build();
+
+            /// <inheritdoc/>
+            public ValueTask HandleAsync(PrepareRevocationRequestContext context)
+            {
+                if (context is null)
+                {
+                    throw new ArgumentNullException(nameof(context));
+                }
+
+                // This handler only applies to System.Net.Http requests. If the HTTP request cannot be resolved,
+                // this may indicate that the request was incorrectly processed by another client stack.
+                var request = context.Transaction.GetHttpRequestMessage() ??
+                    throw new InvalidOperationException(SR.GetResourceString(SR.ID0173));
+
+                // Zendesk requires using bearer authentication with the token that is going to be revoked.
+                if (context.Registration.ProviderType is ProviderTypes.Zendesk)
+                {
+                    request.Headers.Authorization = new AuthenticationHeaderValue(Schemes.Bearer, context.Token);
+
+                    // Remove the token from the request payload to ensure it's not sent twice.
+                    context.Request.Token = null;
+                }
+
+                return default;
+            }
+        }
+
         /// <summary>
         /// Contains the logic responsible for normalizing the returned content
         /// type of revocation responses for the providers that require it.

src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationHandlers.Userinfo.cs

@@ -406,8 +406,9 @@ public static partial class OpenIddictClientWebIntegrationHandlers
                     ProviderTypes.ExactOnline => new(context.Response["d"]?["results"]?[0]?.GetNamedParameters() ??
                         throw new InvalidOperationException(SR.FormatID0334("d/results/0"))),
 
-                    // Fitbit and Todoist return a nested "user" object.
+                    // Fitbit, Todoist and Zendesk return a nested "user" object.
-                    ProviderTypes.Fitbit or ProviderTypes.Todoist => new(context.Response["user"]?.GetNamedParameters() ??
+                    ProviderTypes.Fitbit or ProviderTypes.Todoist or ProviderTypes.Zendesk
+                        => new(context.Response["user"]?.GetNamedParameters() ??
                         throw new InvalidOperationException(SR.FormatID0334("user"))),
 
                     // Harvest returns a nested "user" object and a collection of "accounts".

src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationProviders.xml

@@ -2153,6 +2153,35 @@
     <Environment Issuer="https://api.login.yahoo.com/" />
   </Provider>
 
+  <!--
+                                        ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
+                                        ██ ▄▄▄ ██ ▄▄▄██ ▀██ ██ ▄▄▀██ ▄▄▄██ ▄▄▄ ██ █▀▄██
+                                        ██▀▀▀▄▄██ ▄▄▄██ █ █ ██ ██ ██ ▄▄▄██▄▄▄▀▀██ ▄▀███
+                                        ██ ▀▀▀ ██ ▀▀▀██ ██▄ ██ ▀▀ ██ ▀▀▀██ ▀▀▀ ██ ██ ██
+                                        ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
+  -->
+
+  <Provider Name="Zendesk" Id="5577b117-1f3d-464f-b987-aabf7c0ab3f7"
+            Documentation="https://support.zendesk.com/hc/en-us/articles/4408845965210-Using-OAuth-authentication-with-your-application">
+    <!--
+      Note: Zendesk is a multitenant provider that relies on subdomains to identify instances.
+      As such, the following URLs all include a {settings.Tenant} placeholder that will be dynamically
+      replaced by OpenIddict at runtime by the tenant configured in the Zendesk settings.
+    -->
+
+    <Environment Issuer="https://{settings.Tenant}.zendesk.com/">
+      <Configuration AuthorizationEndpoint="https://{settings.Tenant}.zendesk.com/oauth/authorizations/new"
+                     TokenEndpoint="https://{settings.Tenant}.zendesk.com/oauth/tokens"
+                     UserInfoEndpoint="https://{settings.Tenant}.zendesk.com/api/v2/users/me"
+                     RevocationEndpoint="https://{settings.Tenant}.zendesk.com/api/v2/oauth/tokens/current.json">
+        <CodeChallengeMethod Value="S256" />
+      </Configuration>
+    </Environment>
+
+    <Setting PropertyName="Tenant" ParameterName="tenant" Type="String" Required="true"
+             Description="Gets or sets the tenant used to identify the Zendesk instance" />
+  </Provider>
+
   <!--
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