WireMock.Net-wiremock/src/WireMock.Net/Plugin/PluginLoader.cs

using System;
using System.Collections.Concurrent;
using System.IO;
using System.Linq;
using System.Reflection;

namespace WireMock.Plugin
{
    internal static class PluginLoader
    {
        private static readonly ConcurrentDictionary<Type, Type> Assemblies = new ConcurrentDictionary<Type, Type>();

        public static T Load<T>(params object[] args) where T : class
        {
            var foundType = Assemblies.GetOrAdd(typeof(T), (type) =>
            {
                var files = Directory.GetFiles(Directory.GetCurrentDirectory(), "*.dll");

                Type pluginType = null;
                foreach (var file in files)
                {
                    try
                    {
                        var assembly = Assembly.Load(new AssemblyName
                        {
                            Name = Path.GetFileNameWithoutExtension(file)
                        });

                        pluginType = GetImplementationTypeByInterface<T>(assembly);
                        if (pluginType != null)
                        {
                            break;
                        }
                    }
                    catch
                    {
                        // no-op: just try next .dll
                    }
                }

                if (pluginType != null)
                {
                    return pluginType;
                }

                throw new DllNotFoundException($"No dll found which implements type '{type}'");
            });

            return (T)Activator.CreateInstance(foundType, args);
        }

        private static Type GetImplementationTypeByInterface<T>(Assembly assembly)
        {
            return assembly.GetTypes().FirstOrDefault(t => typeof(T).IsAssignableFrom(t) && !t.GetTypeInfo().IsInterface);
        }
    }
}