GraphQL - custom scalar support

examples/WireMock.Net.Console.Net452.Classic/MainApp.cs

@@ -43,6 +43,9 @@ public class Todo
     public static class MainApp
     {
         private const string TestSchema = @"
+  scalar DateTime
+  scalar MyCustomScalar
+
   input MessageInput {
     content: String
     author: String
@@ -56,6 +59,7 @@ type Message {
 
   type Mutation {
     createMessage(input: MessageInput): Message
+    createAnotherMessage(x: MyCustomScalar, dt: DateTime): Message
     updateMessage(id: ID!, input: MessageInput): Message
   }
 
@@ -168,11 +172,12 @@ public static void Run()
 
             // server.AllowPartialMapping();
 #if GRAPHQL
+            var customScalars = new Dictionary<string, Type> { { "MyCustomScalar", typeof(int) } };
             server
                 .Given(Request.Create()
                     .WithPath("/graphql")
                     .UsingPost()
-                    .WithGraphQLSchema(TestSchema)
+                    .WithGraphQLSchema(TestSchema, customScalars)
                 )
                 .RespondWith(Response.Create()
                     .WithBody("GraphQL is ok")

src/WireMock.Net.Abstractions/Admin/Mappings/MatcherModel.cs

@@ -1,3 +1,6 @@
+using System.Collections.Generic;
+using System;
+
 namespace WireMock.Admin.Mappings;
 
 /// <summary>
@@ -75,6 +78,16 @@ public class MatcherModel
     #endregion
 
     #region XPathMatcher
+    /// <summary>
+    /// Array of namespace prefix and uri. (optional)
+    /// </summary>
     public XmlNamespace[]? XmlNamespaceMap { get; set; }
     #endregion
+
+    #region GraphQLMatcher
+    /// <summary>
+    /// Mapping of custom GraphQL Scalar name to ClrType.  (optional)
+    /// </summary>
+    public IDictionary<string, Type>? CustomScalars { get; set; }
+    #endregion
 }

src/WireMock.Net/Matchers/GraphQLMatcher.cs

@@ -6,10 +6,15 @@
 using AnyOfTypes;
 using GraphQL;
 using GraphQL.Types;
+using GraphQLParser;
+using GraphQLParser.AST;
 using Newtonsoft.Json;
 using Stef.Validation;
+using WireMock.Exceptions;
 using WireMock.Extensions;
+using WireMock.Matchers.Models;
 using WireMock.Models;
+using WireMock.Util;
 
 namespace WireMock.Matchers;
 
@@ -36,14 +41,40 @@ private sealed class GraphQLRequest
     public MatchBehaviour MatchBehaviour { get; }
 
     /// <summary>
-    /// Initializes a new instance of the <see cref="LinqMatcher"/> class.
+    /// An optional dictionary defining the custom Scalar and the type.
+    /// </summary>
+    public IDictionary<string, Type>? CustomScalars { get; }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="GraphQLMatcher"/> class.
+    /// </summary>
+    /// <param name="schema">The schema.</param>
+    /// <param name="matchBehaviour">The match behaviour. (default = "AcceptOnMatch")</param>
+    /// <param name="matchOperator">The <see cref="Matchers.MatchOperator"/> to use. (default = "Or")</param>
+    public GraphQLMatcher(
+        AnyOf<string, StringPattern, ISchema> schema,
+        MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch,
+        MatchOperator matchOperator = MatchOperator.Or
+    ) : this(schema, null, matchBehaviour, matchOperator)
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="GraphQLMatcher"/> class.
     /// </summary>
     /// <param name="schema">The schema.</param>
-    /// <param name="matchBehaviour">The match behaviour.</param>
+    /// <param name="customScalars">A dictionary defining the custom scalars used in this schema. (optional)</param>
+    /// <param name="matchBehaviour">The match behaviour. (default = "AcceptOnMatch")</param>
     /// <param name="matchOperator">The <see cref="Matchers.MatchOperator"/> to use. (default = "Or")</param>
-    public GraphQLMatcher(AnyOf<string, StringPattern, ISchema> schema, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch, MatchOperator matchOperator = MatchOperator.Or)
+    public GraphQLMatcher(
+        AnyOf<string, StringPattern, ISchema> schema,
+        IDictionary<string, Type>? customScalars,
+        MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch,
+        MatchOperator matchOperator = MatchOperator.Or
+    )
     {
         Guard.NotNull(schema);
+        CustomScalars = customScalars;
         MatchBehaviour = matchBehaviour;
         MatchOperator = matchOperator;
 
@@ -137,12 +168,36 @@ private static bool TryGetGraphQLRequest(string input, [NotNullWhen(true)] out G
         }
     }
 
-    private static ISchema BuildSchema(string typeDefinitions)
+    /// <param name="typeDefinitions">A textual description of the schema in SDL (Schema Definition Language) format.</param>
+    private ISchema BuildSchema(string typeDefinitions)
     {
         var schema = Schema.For(typeDefinitions);
 
         // #984
-        schema.RegisterTypes(schema.BuiltInTypeMappings.Select(x => x.graphType).ToArray());
+        var graphTypes = schema.BuiltInTypeMappings.Select(tm => tm.graphType).ToArray();
+        schema.RegisterTypes(graphTypes);
+
+        var doc = Parser.Parse(typeDefinitions);
+        var scalarTypeDefinitions = doc.Definitions
+            .Where(d => d.Kind == ASTNodeKind.ScalarTypeDefinition)
+            .OfType<GraphQLTypeDefinition>();
+
+        foreach (var scalarTypeDefinitionName in scalarTypeDefinitions.Select(s => s.Name.StringValue))
+        {
+            var customScalarGraphTypeName = $"{scalarTypeDefinitionName}GraphType";
+            if (graphTypes.All(t => t.Name != customScalarGraphTypeName)) // Only process when not built-in.
+            {
+                // Check if this custom Scalar is defined in the dictionary
+                if (CustomScalars == null || !CustomScalars.TryGetValue(scalarTypeDefinitionName, out var clrType))
+                {
+                    throw new WireMockException($"The GraphQL Scalar type '{scalarTypeDefinitionName}' is not defined in the CustomScalars dictionary.");
+                }
+
+                // Create a this custom Scalar GraphType (extending the WireMockCustomScalarGraphType<{clrType}> class)
+                var customScalarGraphType = ReflectionUtils.CreateGenericType(customScalarGraphTypeName, typeof(WireMockCustomScalarGraphType<>), clrType);
+                schema.RegisterType(customScalarGraphType);
+            }
+        }
 
         return schema;
     }

src/WireMock.Net/Matchers/Models/WireMockCustomScalarGraphType.cs

@@ -0,0 +1,30 @@
+#if GRAPHQL
+using System;
+using GraphQL.Types;
+
+namespace WireMock.Matchers.Models;
+
+/// <inheritdoc />
+public abstract class WireMockCustomScalarGraphType<T> : ScalarGraphType
+{
+    /// <inheritdoc />
+    public override object? ParseValue(object? value)
+    {
+        switch (value)
+        {
+            case null:
+                return null;
+
+            case T:
+                return value;
+        }
+
+        if (value is string && typeof(T) != typeof(string))
+        {
+            throw new InvalidCastException($"Unable to convert value '{value}' of type '{typeof(string)}' to type '{typeof(T)}'.");
+        }
+
+        return (T)Convert.ChangeType(value, typeof(T));
+    }
+}
+#endif

src/WireMock.Net/Matchers/Request/RequestMessageGraphQLMatcher.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using Stef.Validation;
@@ -25,8 +26,9 @@ public class RequestMessageGraphQLMatcher : IRequestMatcher
     /// </summary>
     /// <param name="matchBehaviour">The match behaviour.</param>
     /// <param name="schema">The schema.</param>
-    public RequestMessageGraphQLMatcher(MatchBehaviour matchBehaviour, string schema) :
-        this(CreateMatcherArray(matchBehaviour, schema))
+    /// <param name="customScalars">A dictionary defining the custom scalars used in this schema. (optional)</param>
+    public RequestMessageGraphQLMatcher(MatchBehaviour matchBehaviour, string schema, IDictionary<string, Type>? customScalars = null) :
+        this(CreateMatcherArray(matchBehaviour, schema, customScalars))
     {
     }
 
@@ -36,8 +38,9 @@ public RequestMessageGraphQLMatcher(MatchBehaviour matchBehaviour, string schema
     /// </summary>
     /// <param name="matchBehaviour">The match behaviour.</param>
     /// <param name="schema">The schema.</param>
-    public RequestMessageGraphQLMatcher(MatchBehaviour matchBehaviour, GraphQL.Types.ISchema schema) :
-        this(CreateMatcherArray(matchBehaviour, new AnyOfTypes.AnyOf<string, Models.StringPattern, GraphQL.Types.ISchema>(schema)))
+    /// <param name="customScalars">A dictionary defining the custom scalars used in this schema. (optional)</param>
+    public RequestMessageGraphQLMatcher(MatchBehaviour matchBehaviour, GraphQL.Types.ISchema schema, IDictionary<string, Type>? customScalars = null) :
+        this(CreateMatcherArray(matchBehaviour, new AnyOfTypes.AnyOf<string, WireMock.Models.StringPattern, GraphQL.Types.ISchema>(schema), customScalars))
     {
     }
 #endif
@@ -89,12 +92,17 @@ private IReadOnlyList<MatchResult> CalculateMatchResults(IRequestMessage request
     }
 
 #if GRAPHQL
-    private static IMatcher[] CreateMatcherArray(MatchBehaviour matchBehaviour, AnyOfTypes.AnyOf<string, Models.StringPattern, GraphQL.Types.ISchema> schema)
+    private static IMatcher[] CreateMatcherArray(
+        MatchBehaviour matchBehaviour,
+        AnyOfTypes.AnyOf<string, WireMock.Models.StringPattern,
+        GraphQL.Types.ISchema> schema,
+        IDictionary<string, Type>? customScalars
+    )
     {
-        return new[] { new GraphQLMatcher(schema, matchBehaviour) }.Cast<IMatcher>().ToArray();
+        return new[] { new GraphQLMatcher(schema, customScalars, matchBehaviour) }.Cast<IMatcher>().ToArray();
     }
 #else
-    private static IMatcher[] CreateMatcherArray(MatchBehaviour matchBehaviour, object schema)
+    private static IMatcher[] CreateMatcherArray(MatchBehaviour matchBehaviour, object schema, IDictionary<string, Type>? customScalars)
     {
         throw new System.NotSupportedException("The GrapQLMatcher can not be used for .NETStandard1.3 or .NET Framework 4.6.1 or lower.");
     }

src/WireMock.Net/RequestBuilders/IGraphQLRequestBuilder.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Collections.Generic;
 using WireMock.Matchers;
 
 namespace WireMock.RequestBuilders;
@@ -15,6 +17,15 @@ public interface IGraphQLRequestBuilder : IMultiPartRequestBuilder
     /// <returns>The <see cref="IRequestBuilder"/>.</returns>
     IRequestBuilder WithGraphQLSchema(string schema, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch);
 
+    /// <summary>
+    /// WithGraphQLSchema: The GraphQL schema as a string.
+    /// </summary>
+    /// <param name="schema">The GraphQL schema.</param>
+    /// <param name="customScalars">A dictionary defining the custom scalars used in this schema. (optional)</param>
+    /// <param name="matchBehaviour">The match behaviour. (Default is <c>MatchBehaviour.AcceptOnMatch</c>).</param>
+    /// <returns>The <see cref="IRequestBuilder"/>.</returns>
+    IRequestBuilder WithGraphQLSchema(string schema, IDictionary<string, Type>? customScalars, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch);
+
 #if GRAPHQL
     /// <summary>
     /// WithGraphQLSchema: The GraphQL schema as a ISchema.
@@ -23,5 +34,14 @@ public interface IGraphQLRequestBuilder : IMultiPartRequestBuilder
     /// <param name="matchBehaviour">The match behaviour. (Default is <c>MatchBehaviour.AcceptOnMatch</c>).</param>
     /// <returns>The <see cref="IRequestBuilder"/>.</returns>
     IRequestBuilder WithGraphQLSchema(GraphQL.Types.ISchema schema, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch);
+
+    /// <summary>
+    /// WithGraphQLSchema: The GraphQL schema as a ISchema.
+    /// </summary>
+    /// <param name="schema">The GraphQL schema.</param>
+    /// <param name="customScalars">A dictionary defining the custom scalars used in this schema. (optional)</param>
+    /// <param name="matchBehaviour">The match behaviour. (Default is <c>MatchBehaviour.AcceptOnMatch</c>).</param>
+    /// <returns>The <see cref="IRequestBuilder"/>.</returns>
+    IRequestBuilder WithGraphQLSchema(GraphQL.Types.ISchema schema, IDictionary<string, Type>? customScalars, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch);
 #endif
 }

src/WireMock.Net/RequestBuilders/Request.WithGraphQL.cs

@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+using System;
 using WireMock.Matchers;
 using WireMock.Matchers.Request;
 
@@ -12,12 +14,26 @@ public IRequestBuilder WithGraphQLSchema(string schema, MatchBehaviour matchBeha
         return this;
     }
 
+    /// <inheritdoc />
+    public IRequestBuilder WithGraphQLSchema(string schema, IDictionary<string, Type>? customScalars, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch)
+    {
+        _requestMatchers.Add(new RequestMessageGraphQLMatcher(matchBehaviour, schema, customScalars));
+        return this;
+    }
+
 #if GRAPHQL
     /// <inheritdoc />
     public IRequestBuilder WithGraphQLSchema(GraphQL.Types.ISchema schema, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch)
     {
         _requestMatchers.Add(new RequestMessageGraphQLMatcher(matchBehaviour, schema));
         return this;
     }
+
+    /// <inheritdoc />
+    public IRequestBuilder WithGraphQLSchema(GraphQL.Types.ISchema schema, IDictionary<string, Type>? customScalars, MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch)
+    {
+        _requestMatchers.Add(new RequestMessageGraphQLMatcher(matchBehaviour, schema, customScalars));
+        return this;
+    }
 #endif
 }

src/WireMock.Net/Serialization/MatcherMapper.cs

@@ -72,7 +72,7 @@ public MatcherMapper(WireMockServerSettings settings)
                 return CreateExactObjectMatcher(matchBehaviour, stringPatterns[0]);
 #if GRAPHQL
             case nameof(GraphQLMatcher):
-                return new GraphQLMatcher(stringPatterns[0].GetPattern(), matchBehaviour, matchOperator);
+                return new GraphQLMatcher(stringPatterns[0].GetPattern(), matcher.CustomScalars, matchBehaviour, matchOperator);
 #endif
 
 #if MIMEKIT
@@ -101,8 +101,7 @@ public MatcherMapper(WireMockServerSettings settings)
                 return new JmesPathMatcher(matchBehaviour, matchOperator, stringPatterns);
 
             case nameof(XPathMatcher):
-                var xmlNamespaces = matcher.XmlNamespaceMap;
-                return new XPathMatcher(matchBehaviour, matchOperator, xmlNamespaces, stringPatterns);
+                return new XPathMatcher(matchBehaviour, matchOperator, matcher.XmlNamespaceMap, stringPatterns);
 
             case nameof(WildcardMatcher):
                 return new WildcardMatcher(matchBehaviour, stringPatterns, ignoreCase, matchOperator);
@@ -164,6 +163,11 @@ public MatcherMapper(WireMockServerSettings settings)
             case XPathMatcher xpathMatcher:
                 model.XmlNamespaceMap = xpathMatcher.XmlNamespaceMap;
                 break;
+#if GRAPHQL
+            case GraphQLMatcher graphQLMatcher:
+                model.CustomScalars = graphQLMatcher.CustomScalars;
+                break;
+#endif
         }
 
         switch (matcher)

src/WireMock.Net/Util/ReflectionUtils.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Concurrent;
+using System.Linq;
+using System.Reflection;
+using System.Reflection.Emit;
+
+namespace WireMock.Util;
+
+internal static class ReflectionUtils
+{
+    private const string DynamicModuleName = "WireMockDynamicModule";
+    private static readonly AssemblyName AssemblyName = new("WireMockDynamicAssembly");
+    private const TypeAttributes ClassAttributes =
+        TypeAttributes.Public |
+        TypeAttributes.Class |
+        TypeAttributes.AutoClass |
+        TypeAttributes.AnsiClass |
+        TypeAttributes.BeforeFieldInit |
+        TypeAttributes.AutoLayout;
+    private static readonly ConcurrentDictionary<string, Type> TypeCache = new();
+
+    public static Type CreateType(string typeName, Type? parentType = null)
+    {
+        return TypeCache.GetOrAdd(typeName, key =>
+        {
+            var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(AssemblyName, AssemblyBuilderAccess.Run);
+            var moduleBuilder = assemblyBuilder.DefineDynamicModule(DynamicModuleName);
+
+            var typeBuilder = moduleBuilder.DefineType(key, ClassAttributes, parentType);
+
+            // Create the type and cache it
+            return typeBuilder.CreateTypeInfo()!.AsType();
+        });
+    }
+
+    public static Type CreateGenericType(string typeName, Type genericTypeDefinition, params Type[] typeArguments)
+    {
+        var genericKey = $"{typeName}_{genericTypeDefinition.Name}_{string.Join(", ", typeArguments.Select(t => t.Name))}";
+
+        return TypeCache.GetOrAdd(genericKey, _ =>
+        {
+            var genericType = genericTypeDefinition.MakeGenericType(typeArguments);
+
+            // Create the type based on the genericType and cache it
+            return CreateType(typeName, genericType);
+        });
+    }
+}