# Hosting IronRuby/DLR in long running applications

**URL:** <https://www.ruby-forum.com/t/hosting-ironruby-dlr-in-long-running-applications/189220>\
**Category:** IronRuby\
**Created:** [May 27, 2010, 12:13am UTC](https://www.ruby-forum.com/t/hosting-ironruby-dlr-in-long-running-applications/189220 "2010-05-27T00:13:06Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Josh\_Flanagan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9e8a1a/32.png) [@Josh\_Flanagan](https://www.ruby-forum.com/u/Josh_Flanagan)\
**Post date:** [May 27, 2010, 12:13am UTC](https://www.ruby-forum.com/t/hosting-ironruby-dlr-in-long-running-applications/189220/1 "2010-05-27T00:13:06Z")

</div>

Following up on this discussion on [ASP.NET](http://ASP.NET):  
[http://rubyforge.org/pipermail/ironruby-core/2010-February/006225.html](http://rubyforge.org/pipermail/ironruby-core/2010-February/006225.html)

We are considering hosting IronRuby in our application ([ASP.NET](http://ASP.NET)  
website & a couple windows services). I am looking for any guidance  
around which objects should be cached, and what should be created on  
the fly. The responses from the previous thread seemed to suggest it  
is safe to cache the ScriptEngine. I’m wondering where else I might  
want to cache, and where I would NOT want to cache (if an object is  
not thread safe, and shouldn’t be used to fulfill multiple  
simultaneous requests).

Specifically, we are using IronRuby to provide some customization to  
the application. For (simplified) example, suppose we wanted to  
provide the ability to customize a greeting. I want to store the  
script that generates the greeting in the web.config (either the  
script itself, or the path to the script).

My theory is that I can create a CompiledCode instance during  
application startup, and then execute the compiled code with different  
scopes for each request (to provide request-specific data). Is this  
the proper/recommended way of executing the same script with different  
data within an application? Is it safe to called CompiledCode.Execute  
from multiple threads simultaneously?

Sample code that shows what I plan to do:

// Perform all these steps in global.asax application\_start  
var scriptFromConfigFile = @“”“Hi #{ctx.first\_name}  
#{ctx.last\_name}”“”; // read from web.config appSettings  
var scriptEngine = IronRuby.Ruby.CreateEngine();  
//GreetingScript is cached as a singleton so that it is available to  
requests  
var GreetingScript =  
scriptEngine.CreateScriptSourceFromString(scriptFromConfigFile).Compile();

// during each individual web request, change the context object  
passed to the script  
var scriptScope = GreetingScript.Engine.CreateScope();  
scriptScope.SetVariable(“ctx”, new {FirstName=“John”, LastName=“Doe”});  
var greeting = GreetingScript.Execute(scriptScope);

Console.WriteLine(greeting);

---

<div class="post-metadata">

**Author:** ![Josh\_Flanagan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9e8a1a/32.png) [@Josh\_Flanagan](https://www.ruby-forum.com/u/Josh_Flanagan)\
**Post date:** [May 27, 2010, 7:06am UTC](https://www.ruby-forum.com/t/hosting-ironruby-dlr-in-long-running-applications/189220/2 "2010-05-27T07:06:54Z")

</div>

Your theory is all right. It is CompiledCode’s purpose to be executed  
many times against different scopes. CompiledCode.Execute is thread-safe  
provided that the script being executed and the scope storage are. The  
data-structures IronRuby and DLR use internally are thread-safe. If you  
use ScriptScope with default storage (you do so in the sample below) and  
if the script doesn’t modify shared state not protected by a lock than  
everything should work just fine.

Tomas