custom standard value tokens

Sitecore provides the ability to use a number of tokens, set on a templates Standard Values, that will be replaced during item creation. Further information and a list of available tokens can be found here

In order to implement custom tokens, we need to implement a custom ExpandInitialFieldValueProcessor; and then patch that processor via configuration.

This is example is going to provide a $path token and replace it with the full (relative to the website route) path.

Processor C# File:

public class PathStandardValueProcessor : ExpandInitialFieldValueProcessor
{
    private const string _pathToken = "$path";
    private const string _basePath = "/sitecore/content/{website_name}/Home/";

    public override void Process(ExpandInitialFieldValueArgs args)
    {
        if (args.SourceField.Value.Contains(_pathToken))
        {
            if (args.TargetItem != null && args.TargetItem.Parent != null)
            {
                var fullPath = args.TargetItem.Paths.FullPath;
                var sitePath = fullPath.Replace(_basePath, string.Empty);

                args.Result = args.Result.Replace(_pathToken, sitePath);
            }
        }
    }
}

Custom Configuration Patch File:

<?xml version="1.0" encoding="utf-8"?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:role="http://www.sitecore.net/xmlconfig/role/">
    <sitecore>
        <pipelines>
		    <expandInitialFieldValue>
				<processor type="namespace.PathStandardValueProcessor, Project.Name" patch:after="processor[@type='type=Sitecore.Pipelines.ExpandInitialFieldValue.ReplaceVariables, Sitecore.Kernel']" />
			</expandInitialFieldValue>
        </pipelines>
    </sitecore>
</configuration>