Using RazorEngine to parse Razor templates concurrently

Question

I\'m using the RazorEngine library (http://razorengine.codeplex.com/) in an MVC 3 web application to parse strings (that aren\'t views) using the Razor templating language.<

Answer 1

Update: According to a blog post from their team, the latest version 3.x (on Github) is now thread-safe. I have not vetted the veracity of its thread-safety, but assume it has been implemented properly. Please consider the rest of this answer useful only for historical purposes.

---

Judging from the code, this project doesn't look remotely thread-safe.

Razor.Parse:

public static string Parse<T>(string template, T model, string name = null)
{
    return DefaultTemplateService.Parse<T>(template, model, name);
}

TemplateService.Parse:

public string Parse<T>(string template, T model, string name = null)
{
    var instance = GetTemplate(template, typeof(T), name);
    ...
}

TemplateService.GetTemplate:

internal ITemplate GetTemplate(string template, Type modelType, string name)
{
    if (!string.IsNullOrEmpty(name))
        if (templateCache.ContainsKey(name))
            return templateCache[name];

    var instance = CreateTemplate(template, modelType);

    if (!string.IsNullOrEmpty(name))
        if (!templateCache.ContainsKey(name))
            templateCache.Add(name, instance);

    return instance;
}

So, Razor.Parse is a static method. DefaultTemplateService is a static property on Razor, and Parse and GetTemplate are instance methods, but effectively invoked statically because of the static DefaultTemplateService. This means all threads go through the same instance and go through GetTemplate. You'll notice that GetTemplate mutates state (templateCache) without acquiring any locks. Therefore, this code is not threadsafe.