Extend TypeLoader (#1069)

* Extend PluginLoader

* rename

Author: StefH

WireMock.Net Solution.sln.DotSettings

@@ -23,6 +23,7 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=WWW/@EntryIndexedValue">WWW</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=XMS/@EntryIndexedValue">XMS</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=XUA/@EntryIndexedValue">XUA</s:String>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Dlls/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Flurl/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=funcs/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Grpc/@EntryIndexedValue">True</s:Boolean>

src/WireMock.Net/Plugin/PluginLoader.cs

@@ -8,7 +8,6 @@
 using WireMock.Extensions;
 using WireMock.Matchers;
 using WireMock.Models;
-using WireMock.Plugin;
 using WireMock.Settings;
 using WireMock.Util;
 
@@ -53,7 +52,7 @@ public MatcherMapper(WireMockServerSettings settings)
             case "CSharpCodeMatcher":
                 if (_settings.AllowCSharpCodeMatcher == true)
                 {
-                    return PluginLoader.Load<ICSharpCodeMatcher>(matchBehaviour, matchOperator, stringPatterns);
+                    return TypeLoader.Load<ICSharpCodeMatcher>(matchBehaviour, matchOperator, stringPatterns);
                 }
 
                 throw new NotSupportedException("It's not allowed to use the 'CSharpCodeMatcher' because WireMockServerSettings.AllowCSharpCodeMatcher is not set to 'true'.");

src/WireMock.Net/Serialization/MatcherMapper.cs

@@ -0,0 +1,89 @@
+using System;
+using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using Stef.Validation;
+
+namespace WireMock.Util;
+
+internal static class TypeLoader
+{
+    private static readonly ConcurrentDictionary<string, Type> Assemblies = new();
+
+    public static TInterface Load<TInterface>(params object[] args) where TInterface : class
+    {
+        var key = typeof(TInterface).FullName!;
+
+        var pluginType = Assemblies.GetOrAdd(key, _ =>
+        {
+            if (TryFindTypeInDlls<TInterface>(null, out var foundType))
+            {
+                return foundType;
+            }
+
+            throw new DllNotFoundException($"No dll found which implements Interface '{key}'.");
+        });
+
+        return (TInterface)Activator.CreateInstance(pluginType, args)!;
+    }
+
+    public static TInterface LoadByFullName<TInterface>(string implementationTypeFullName, params object[] args) where TInterface : class
+    {
+        Guard.NotNullOrEmpty(implementationTypeFullName);
+
+        var @interface = typeof(TInterface).FullName;
+        var key = $"{@interface}_{implementationTypeFullName}";
+
+        var pluginType = Assemblies.GetOrAdd(key, _ =>
+        {
+            if (TryFindTypeInDlls<TInterface>(implementationTypeFullName, out var foundType))
+            {
+                return foundType;
+            }
+
+            throw new DllNotFoundException($"No dll found which implements Interface '{@interface}' and has FullName '{implementationTypeFullName}'.");
+        });
+
+        return (TInterface)Activator.CreateInstance(pluginType, args)!;
+    }
+
+    private static bool TryFindTypeInDlls<TInterface>(string? implementationTypeFullName, [NotNullWhen(true)] out Type? pluginType) where TInterface : class
+    {
+        foreach (var file in Directory.GetFiles(Directory.GetCurrentDirectory(), "*.dll"))
+        {
+            try
+            {
+                var assembly = Assembly.Load(new AssemblyName
+                {
+                    Name = Path.GetFileNameWithoutExtension(file)
+                });
+
+                if (TryGetImplementationTypeByInterfaceAndOptionalFullName<TInterface>(assembly, implementationTypeFullName, out pluginType))
+                {
+                    return true;
+                }
+            }
+            catch
+            {
+                // no-op: just try next .dll
+            }
+        }
+
+        pluginType = null;
+        return false;
+    }
+
+    private static bool TryGetImplementationTypeByInterfaceAndOptionalFullName<T>(Assembly assembly, string? implementationTypeFullName, [NotNullWhen(true)] out Type? type)
+    {
+        type = assembly
+            .GetTypes()
+            .FirstOrDefault(t =>
+                typeof(T).IsAssignableFrom(t) && !t.GetTypeInfo().IsInterface &&
+                (implementationTypeFullName == null || string.Equals(t.FullName, implementationTypeFullName, StringComparison.OrdinalIgnoreCase))
+            );
+
+        return type != null;
+    }
+}

src/WireMock.Net/Util/TypeLoader.cs

@@ -0,0 +1,65 @@
+using System;
+using AnyOfTypes;
+using FluentAssertions;
+using WireMock.Matchers;
+using WireMock.Models;
+using WireMock.Util;
+using Xunit;
+
+namespace WireMock.Net.Tests.Util;
+
+public class TypeLoaderTests
+{
+    public interface IDummyInterfaceNoImplementation
+    {
+    }
+
+    public interface IDummyInterfaceWithImplementation
+    {
+    }
+
+    public class DummyClass : IDummyInterfaceWithImplementation
+    {
+    }
+
+    [Fact]
+    public void Load_ByInterface()
+    {
+        // Act
+        AnyOf<string, StringPattern> pattern = "x";
+        var result = TypeLoader.Load<ICSharpCodeMatcher>(MatchBehaviour.AcceptOnMatch, MatchOperator.Or, pattern);
+
+        // Assert
+        result.Should().NotBeNull();
+    }
+
+    [Fact]
+    public void Load_ByInterfaceAndFullName()
+    {
+        // Act
+        var result = TypeLoader.LoadByFullName<IDummyInterfaceWithImplementation>(typeof(DummyClass).FullName!);
+
+        // Assert
+        result.Should().BeOfType<DummyClass>();
+    }
+
+    [Fact]
+    public void Load_ByInterface_ButNoImplementationFoundForInterface_ThrowsException()
+    {
+        // Act
+        Action a = () => TypeLoader.Load<IDummyInterfaceNoImplementation>();
+
+        // Assert
+        a.Should().Throw<DllNotFoundException>().WithMessage("No dll found which implements Interface 'WireMock.Net.Tests.Util.TypeLoaderTests+IDummyInterfaceNoImplementation'.");
+    }
+
+    [Fact]
+    public void Load_ByInterfaceAndFullName_ButNoImplementationFoundForInterface_ThrowsException()
+    {
+        // Act
+        Action a = () => TypeLoader.LoadByFullName<IDummyInterfaceWithImplementation>("xyz");
+
+        // Assert
+        a.Should().Throw<DllNotFoundException>().WithMessage("No dll found which implements Interface 'WireMock.Net.Tests.Util.TypeLoaderTests+IDummyInterfaceWithImplementation' and has FullName 'xyz'.");
+    }
+}