Add Basecamp to the list of supported providers

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

@@ -0,0 +1,62 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
+ * See https://github.com/openiddict/openiddict-core for more information concerning
+ * the license and the contributors participating to this project.
+ */
+
+using System.Collections.Immutable;
+using static OpenIddict.Client.WebIntegration.OpenIddictClientWebIntegrationConstants;
+
+namespace OpenIddict.Client.WebIntegration;
+
+public static partial class OpenIddictClientWebIntegrationHandlers
+{
+    public static class Authentication
+    {
+        public static ImmutableArray<OpenIddictClientHandlerDescriptor> DefaultHandlers { get; } = ImmutableArray.Create(
+            /*
+             * Authorization request preparation:
+             */
+            MapNonStandardRequestParameters.Descriptor);
+
+        /// <summary>
+        /// Contains the logic responsible for mapping non-standard request parameters
+        /// to their standard equivalent for the providers that require it.
+        /// </summary>
+        public sealed class MapNonStandardRequestParameters : IOpenIddictClientHandler<PrepareAuthorizationRequestContext>
+        {
+            /// <summary>
+            /// Gets the default descriptor definition assigned to this handler.
+            /// </summary>
+            public static OpenIddictClientHandlerDescriptor Descriptor { get; }
+                = OpenIddictClientHandlerDescriptor.CreateBuilder<PrepareAuthorizationRequestContext>()
+                    .UseSingletonHandler<MapNonStandardRequestParameters>()
+                    .SetOrder(int.MinValue + 100_000)
+                    .SetType(OpenIddictClientHandlerType.BuiltIn)
+                    .Build();
+
+            /// <inheritdoc/>
+            public ValueTask HandleAsync(PrepareAuthorizationRequestContext context)
+            {
+                if (context is null)
+                {
+                    throw new ArgumentNullException(nameof(context));
+                }
+
+                // Some providers implement old drafts of the OAuth 2.0 specification that didn't support
+                // the "response_type" parameter but relied on a "type" parameter to determine the type
+                // of flow (web server or user agent-based). Since the "user_agent" value more or less
+                // corresponds to the legacy OAuth 2.0-only implicit flow, it is deliberately not
+                // supported, so the only supported value is "web_server" (aka authorization code flow).
+
+                if (context.Registration.ProviderName is Providers.Basecamp)
+                {
+                    context.Request["type"] = "web_server";
+                    context.Request.ResponseType = null;
+                }
+
+                return default;
+            }
+        }
+    }
+}

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

@@ -26,6 +26,7 @@ public static partial class OpenIddictClientWebIntegrationHandlers
             /*
              * Token request preparation:
              */
+            MapNonStandardRequestParameters.Descriptor,
             AttachNonStandardBasicAuthenticationCredentials.Descriptor,
             AttachNonStandardRequestHeaders.Descriptor,
             AttachNonStandardQueryStringParameters.Descriptor,
@@ -36,6 +37,51 @@ public static partial class OpenIddictClientWebIntegrationHandlers
              */
             MapNonStandardResponseParameters.Descriptor);
 
+        /// <summary>
+        /// Contains the logic responsible for mapping non-standard request parameters
+        /// to their standard equivalent for the providers that require it.
+        /// </summary>
+        public sealed class MapNonStandardRequestParameters : IOpenIddictClientHandler<PrepareTokenRequestContext>
+        {
+            /// <summary>
+            /// Gets the default descriptor definition assigned to this handler.
+            /// </summary>
+            public static OpenIddictClientHandlerDescriptor Descriptor { get; }
+                = OpenIddictClientHandlerDescriptor.CreateBuilder<PrepareTokenRequestContext>()
+                    .UseSingletonHandler<MapNonStandardRequestParameters>()
+                    .SetOrder(int.MinValue + 100_000)
+                    .SetType(OpenIddictClientHandlerType.BuiltIn)
+                    .Build();
+
+            /// <inheritdoc/>
+            public ValueTask HandleAsync(PrepareTokenRequestContext context)
+            {
+                if (context is null)
+                {
+                    throw new ArgumentNullException(nameof(context));
+                }
+
+                // Some providers implement old drafts of the OAuth 2.0 specification that
+                // didn't support the "response_type" parameter but relied on a "type"
+                // parameter to determine the type of request (web server or refresh).
+
+                if (context.Registration.ProviderName is Providers.Basecamp)
+                {
+                    context.Request["type"] = context.Request.GrantType switch
+                    {
+                        GrantTypes.AuthorizationCode => "web_server",
+                        GrantTypes.RefreshToken => "refresh",
+
+                        _ => null
+                    };
+
+                    context.Request.GrantType = null;
+                }
+
+                return default;
+            }
+        }
+
         /// <summary>
         /// Contains the logic responsible for attaching the client credentials to the HTTP Authorization
         /// header using a non-standard construction logic for the providers that require it.
@@ -259,8 +305,8 @@ public static partial class OpenIddictClientWebIntegrationHandlers
         }
 
         /// <summary>
-        /// Contains the logic responsible for attaching non-standard query string
-        /// parameters to the token request for the providers that require it.
+        /// Contains the logic responsible for mapping non-standard response parameters
+        /// to their standard equivalent for the providers that require it.
         /// </summary>
         public sealed class MapNonStandardResponseParameters : IOpenIddictClientHandler<ExtractTokenResponseContext>
         {

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

@@ -257,6 +257,13 @@ public static partial class OpenIddictClientWebIntegrationHandlers
 
                 context.Response = context.Registration.ProviderName switch
                 {
+                    // Basecamp returns a nested "identity" object and a collection of "accounts".
+                    Providers.Basecamp => new(context.Response["identity"]?.GetNamedParameters() ??
+                        throw new InvalidOperationException(SR.FormatID0334("identity")))
+                    {
+                        ["accounts"] = context.Response["accounts"]
+                    },
+
                     // Fitbit returns a nested "user" object.
                     Providers.Fitbit => new(context.Response["user"]?.GetNamedParameters() ??
                         throw new InvalidOperationException(SR.FormatID0334("user"))),

src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationHandlers.cs

@@ -41,6 +41,7 @@ public static partial class OpenIddictClientWebIntegrationHandlers
         FormatNonStandardScopeParameter.Descriptor,
         IncludeStateParameterInRedirectUri.Descriptor,
         AttachAdditionalChallengeParameters.Descriptor)
+        .AddRange(Authentication.DefaultHandlers)
         .AddRange(Discovery.DefaultHandlers)
         .AddRange(Exchange.DefaultHandlers)
         .AddRange(Protection.DefaultHandlers)
@@ -881,7 +882,7 @@ public static partial class OpenIddictClientWebIntegrationHandlers
 
             // By default, Google doesn't return a refresh token but allows sending an "access_type"
             // parameter to retrieve one (but it is only returned during the first authorization dance).
-            if (context.Registration.ProviderName is Providers.Google)
+            else if (context.Registration.ProviderName is Providers.Google)
             {
                 var options = context.Registration.GetGoogleOptions();
 

src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationProviders.xml

@@ -86,6 +86,33 @@
     <Environment Issuer="https://app.asana.com/api/1.0" />
   </Provider>
 
+  <!--
+                                        ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
+                                        ██ ▄▄▀█ ▄▄▀██ ▄▄▄ ██ ▄▄▄██ ▄▄▀█ ▄▄▀██ ▄▀▄ ██ ▄▄ ██
+                                        ██ ▄▄▀█ ▀▀ ██▄▄▄▀▀██ ▄▄▄██ ████ ▀▀ ██ █ █ ██ ▀▀ ██
+                                        ██ ▀▀ █ ██ ██ ▀▀▀ ██ ▀▀▀██ ▀▀▄█ ██ ██ ███ ██ █████
+                                        ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
+  -->
+
+  <Provider Name="Basecamp" Documentation="https://github.com/basecamp/api/blob/master/sections/authentication.md">
+    <!--
+      Note: Basecamp implements an old draft of the OAuth 2.0 specification and doesn't support the
+      "response_type" and "grant_type" parameters adopted in the final version of the standard.
+
+      To work around that, these parameters are dynamically mapped to "type=web_server" or "type=refresh"
+      depending on the desired flow (and whether the request is an authorization or token request).
+    -->
+
+    <Environment Issuer="https://launchpad.37signals.com/">
+      <Configuration AuthorizationEndpoint="https://launchpad.37signals.com/authorization/new"
+                     TokenEndpoint="https://launchpad.37signals.com/authorization/token"
+                     UserinfoEndpoint="https://launchpad.37signals.com/authorization.json">
+        <GrantType Value="authorization_code" />
+        <GrantType Value="refresh_token" />
+      </Configuration>
+    </Environment>
+  </Provider>
+
   <!--
                                       ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
                                       ██ ▄▄▀█ ▄▄▀█▄▄ ▄▄█▄▄ ▄▄██ █████ ▄▄▄█████ ▀██ ██ ▄▄▄█▄▄ ▄▄██

src/OpenIddict.Client/OpenIddictClientEvents.Exchange.cs

@@ -36,12 +36,20 @@ public static partial class OpenIddictClientEvents
         /// <summary>
         /// Gets or sets the grant type sent to the token endpoint.
         /// </summary>
-        public string? GrantType { get; set; }
+        public string? GrantType
+        {
+            get => Request.GrantType;
+            set => Request.GrantType = value;
+        }
 
         /// <summary>
         /// Gets or sets the authorization code sent to the token endpoint, if applicable.
         /// </summary>
-        public string? AuthorizationCode { get; set; }
+        public string? AuthorizationCode
+        {
+            get => Request.Code;
+            set => Request.Code = value;
+        }
     }
 
     /// <summary>