Roslyn C# Scripting with Cache

RoslynScriptingCSharpTestSample.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Scripting;
using Microsoft.CodeAnalysis.Scripting.CSharp;

namespace RoslynScriptingTest
{
    /// <summary>
    /// Pure sample code. No exception handling. (Syntax errors in scripts throw exceptions at RunAsync())
    /// </summary>
    public static class ScriptEngine
    {
        public static readonly Dictionary<string,Script> Scripts = new Dictionary<string, Script>();
        private static IEnumerable<Assembly> _references; 
        /// <summary>
        /// Executes and caches a script. Returns true if executed cached script.
        /// </summary>
        /// <param name="code">C# code to execute</param>
        /// <returns>false if it had to be compiled. true if it had a cached version</returns>
        public static async Task<bool> ExecuteAsync(string code)
        {
            if (Scripts.ContainsKey(code))
            {
                await Scripts[code].RunAsync();
                return true;
            }
            var script = CSharpScript.Create(code, GetScriptOptions());
            await script.RunAsync();
            Scripts.Add(code, script);
            return false;
        }
        /// <summary>
        /// Forces building/compilation of the code you pass it. Caches the script for faster execution.
        /// </summary>
        /// <param name="code">C# code to compile and cache</param>
        public static void PreCompile(string code)
        {
            var script = CSharpScript.Create(code, GetScriptOptions());
            script.Build();
            Scripts.Add(code, script);
        } 

        /// <summary>
        /// Extendable function to setup script options. Currently adding all referenced assemblies to the script engine.
        /// </summary>
        /// <returns>ScriptOptions with all currently loaded assemblies</returns>
        private static ScriptOptions GetScriptOptions()
        {
            if(_references == null)
                _references = AppDomain.CurrentDomain.GetAssemblies().Where(assembly=> assembly.Location != string.Empty);
            return ScriptOptions.Default.WithReferences(_references);
        }
    }
    
    public static class Program
    {
        private static void Main()
        {
            Task.Run(async () =>
            {
                Console.WriteLine("Test #1 - Executing same code twice. Should return: false, true");
                Console.WriteLine("Cached: " + await ScriptEngine.ExecuteAsync(@"using System; Console.WriteLine(""Hello World"");"));
                Console.WriteLine("Cached: " + await ScriptEngine.ExecuteAsync(@"using System; Console.WriteLine(""Hello World"");"));
                Thread.Sleep(3000);
                Console.WriteLine("Test #2 - Precompiling same code and executing twice. Should return: true, true");
                ScriptEngine.Scripts.Clear();
                ScriptEngine.PreCompile(@"using System; Console.WriteLine(""Hello World"");");
                Console.WriteLine("Cached: " + await ScriptEngine.ExecuteAsync(@"using System; Console.WriteLine(""Hello World"");"));
                Console.WriteLine("Cached: " + await ScriptEngine.ExecuteAsync(@"using System; Console.WriteLine(""Hello World"");"));
            });

            while (true)
            {
                Console.ReadLine();
            }
        }
    }
  }