initial commit

App_Code/ViewScriptTagHelper.cs

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+using Microsoft.AspNetCore.Mvc.Rendering;
+using Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+
+namespace Library;
+
+public class ViewScriptTagHelper : TagHelper
+{
+	private readonly IWebHostEnvironment environment;
+	private readonly IFileVersionProvider fileVersionProvider;
+	private const string AppendVersionAttributeName = "append-version";
+
+	public ViewScriptTagHelper( IWebHostEnvironment environment , IFileVersionProvider fileVersionProvider )
+	{
+		this.environment = environment;
+		this.fileVersionProvider = fileVersionProvider;
+	}
+
+	[ViewContext]
+	public ViewContext? ViewContext { get; set; }
+
+	/// <summary>
+	/// Value indicating if file version should be appended to src urls.
+	/// </summary>
+	/// <remarks>
+	/// A query string "v" with the encoded content of the file is added.
+	/// </remarks>
+	[HtmlAttributeName( AppendVersionAttributeName )]
+	public bool? AppendVersion { get; set; }
+
+	public override void Process( TagHelperContext context , TagHelperOutput output )
+	{
+		// remove the `page-script` tag if script doesn't exist
+		output.TagName = null;
+		output.TagMode = TagMode.StartTagAndEndTag;
+
+		var viewPath = ViewContext?.View.Path;
+		var src = $"{viewPath}.js";
+
+		/* When the app is published, the framework automatically moves the script to the web root.
+           So we should check both places, with the content root first for development */
+		var fileInfo = environment.ContentRootFileProvider.GetFileInfo(src) ??
+					   environment.WebRootFileProvider.GetFileInfo(src);
+
+		if ( fileInfo is { Exists: true } )
+		{
+			// switch it to script now
+			output.TagName = "script";
+			output.Content = new DefaultTagHelperContent( );
+
+			if ( AppendVersion == true )
+			{
+				// people love their cache busting versions
+				src = fileVersionProvider.AddFileVersionToPath( src , src );
+			}
+
+			output.Attributes.Add( "src" , src );
+		}
+	}
+}