Like most, our front end developers write CSS in LESS or SASS and then use Gulp to compile the result. This is great but up until recently both the compiled and source style files would end up in our source control repository.

While this isn't a major issue it was more of an annoyance factor when doing a merge that the compiled file would need to be merged as well as the source files. Any conflicts in bundled/minified files also can become problematic to solve. As well as this it also just seems wrong to have both files in a repo, effectively duplicating the file. After all we wouldn't put compiled dll's into a repo with their source.

Our solution was to get the build server to start running the gulp tasks to produce the bundled files.

Step 1 - Install Node on the build server

To start we need NodeJS installed on the build server. This allows extensions to be installed via NPM (Node Package Manager), it's a similar thing to NuGet,

Step 2 - Install the TeamCity plugin for NodeJS

To add built steps for Node and Gulp we need to install a plugin to make them available. Lucking there is one that does such a thing here https://github.com/jonnyzzz/TeamCity.Node

The actual build of the plugin you can download from Jetbrains team city here https://teamcity.jetbrains.com/viewType.html?buildTypeId=bt434. Just login as guest and then download the latest zip from the artifacts of the last build.

To install the plug you need to copy the zip to Team City's plugin folder. For me this was C:\ProgramData\JetBrains\TeamCity\plugins, if your having trouble finding your's just go to Administration > Global Settings in Team City and it will tell you the data directory. The plugin folder will be in there.

Restart the TeamCity server and the plugin should now show under Administration > Plugins List

Step 3 - Add a NPM Setup build step

The NPM step with a command of install will pick up dependencies and get the files.

Step 4 - Add a Gulp build step

In your gulp step add the path to the gulp file and the tasks in your gulp file that need to be run. I'm using a gulp file that our front end devs had already created for the solution that contained as task for bundling css and another for bundling js.

Step 5 - Including bundled files in a MSBuild

As the bundled files are no longer included in our Visual Studio solution it also means that they arn't included in the set of files which will be included in a publish when MSBuild runs.

To overcome this update the .csproj file with a Target with BeforeTargets set to BeforeBuild and list your bundled files as content. In my example I'm included the whole Content\bundles folder

There's various ways to add bundling and minification to a site, but one of the easiest is to use Microsoft's support from the Microsoft.AspNet.Web.Optimization package. This implementation has some great features including:

• Automatically create the bundles and minify them as files are changed
• Create unique urls to each version of a bundle to force browser refreshing of the file
• Debug mode which outputs links to the raw files rather than the bundled minified version

The functionality is also fully compatible with Sitecore. To use it in your Sitecore solution follow these steps:

1. Add Microsoft.AspNet.Web.Optimization to your project from NuGet. This is the package from Microsoft that contains the functionality to do bundling and minification

2. Create your CSS and Javascript bundles. Where you put the logic for this is up to you but it will need to run when the application starts. Outside of Sitecore my main development is on bespoke ASP.NET MVC and Web API projects so I like to organise startup scripts into an App_Start folder and reference it from the Application_Start event in the global ascx file.

If you are running a Sitecore instance with multiple sites or if you do not have direct access to the production config files, it may be better to keep the logic separate and use a pipeline to create the bundles.

My bundle definitions would look something like this

And in my Global.asax.cs file I would have some logic like this to call the other function

3. Replace your Javascript/CSS references in your layout or rendering files with a call to render the bundle

Webforms

MVC

4. In your web.config file there are a couple of changes needed to get things to work.

First you need to set an ignore url prefix to stop Sitecore trying to resolve the URL to the bundle. In this example mine is called bundles (note: you should add the prefix the what is already in your config file. e.g. |/bundles)

Next a dependant assembly binding needs to be set up for Web Grease. Without it you will see an error about the Web Grease version number

If you have done this and are still getting a version number error check the assembly binding tag. Older versions of Sitecore have the applies to property set which may be only applying the bindings to .Net 2 and you may be using .Net 4.

5. If you are using IIS7 you will also need to make a change in your web.config file

6. Publish your changes into your Sitecore site. Depending if you have compilation mode set to debug or not you will now either have a bundle reference for all your JavaScript and CSS or the individual file references.

.NETs standard tools for bundling and minification are a great asset to the platform solving a lot of problems with only a few lines of code.

However if using IIS 7.0 you may run into a strange issue where the path to your bundles gets created but a 404 is returned whenever there accessed. The functionality is obviously installed and working otherwise the URL wouldn't be created, but a 404 clearly isn't what you want.

The solution lies in your web.config file by setting runAllManagedModulesForAllRequests to true