Scott Hanselman

ASP.NET Core didn't have a runtime bundler like previous versions of ASP.NET. This was a bummer as I was a fan. Fortunately Mads Kristensen created one and put it on GitHub, called WebOptimizer.

WebOptimizer - ASP.NET Core middleware for bundling and minification of CSS and JavaScript files at runtime. With full server-side and client-side caching to ensure high performance.

I'll try it out on a default ASP.NET Core 2.0 app.

First, assuming I've installed http://dot.net I'll run

C:\Users\scott\Desktop> cd squishyweb

C:\Users\scott\Desktop\squishyweb> dotnet new mvc
The template "ASP.NET Core Web App (Model-View-Controller)" was created successfully.
This template contains technologies from parties other than Microsoft, see https://aka.ms/template-3pn for details.

SNIP

Restore succeeded.

Then I'll add a reference to the WebOptimizer package. Be sure to check the versioning and pick the one you want, or use the latest.

C:\Users\scott\Desktop\squishyweb> dotnet add package LigerShark.WebOptimizer.Core --version 1.0.178-beta 

Add the service in ConfigureServices and add it (I'll do it conditionally, only when in Production) in Configure. Notice I had to put it before UseStaticFiles() because I want it to get the first chance at those requests.

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    services.AddWebOptimizer();
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    else
    {
        app.UseWebOptimizer();
        app.UseExceptionHandler("/Home/Error");
    }

    app.UseStaticFiles();

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
    });
}

After running "dotnet run" I'll request site.css as an example and see it's automatically minimized:

You can control the pipeline with globbing like this:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    services.AddWebOptimizer(pipeline =>
    {
        pipeline.MinifyJsFiles("js/a.js", "js/b.js", "js/c.js");
    });
}

If I wanted to combine some files into an output "file" that'll be held/cached only in memory, I can do that also. To be clear, it'll never touch the disk, it's just a URL. Then I can just refer to it with a <link> within my Razor Page or main Layout.

services.AddWebOptimizer(pipeline =>
{
    pipeline.AddCssBundle("/css/mybundle.css", "css/*.css");
});

WebOptimizer also supports automatic "cache busting" with a ?v= query string created by a TagHelper. It can even compile Scss (Sass) files into CSS. There's plugins for TypeScript, Less, and Markdown too!

WebOptimizer is open source and lives at https://github.com/ligershark/WebOptimizer. Go check it out, kick the tires, and see if it meets your needs! Maybe get involved and make a fix or help with docs! There are already some open issues you could start helping with.

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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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