Umbraco-CMS/src/Umbraco.Web.Common/Extensions/WebHostEnvironmentExtensions.cs

using Microsoft.AspNetCore.Hosting;
using Umbraco.Cms.Core;

namespace Umbraco.Extensions;

/// <summary>
///     Contains extension methods for the <see cref="IWebHostEnvironment" /> interface.
/// </summary>
public static class WebHostEnvironmentExtensions
{
    /// <summary>
    ///     Maps a virtual path to a physical path to the application's web root
    /// </summary>
    /// <remarks>
    ///     Depending on the runtime 'web root', this result can vary. For example in Net Framework the web root and the
    ///     content root are the same, however
    ///     in netcore the web root is /wwwroot therefore this will Map to a physical path within wwwroot.
    /// </remarks>
    public static string MapPathWebRoot(this IWebHostEnvironment webHostEnvironment, string path)
    {
        var root = webHostEnvironment.WebRootPath;

        // Create if missing
        if (string.IsNullOrWhiteSpace(root))
        {
            root = webHostEnvironment.WebRootPath = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot");
        }

        var newPath = path.Replace('/', Path.DirectorySeparatorChar).Replace('\\', Path.DirectorySeparatorChar);

        // TODO: This is a temporary error because we switched from IOHelper.MapPath to HostingEnvironment.MapPathXXX
        // IOHelper would check if the path passed in started with the root, and not prepend the root again if it did,
        // however if you are requesting a path be mapped, it should always assume the path is relative to the root, not
        // absolute in the file system.  This error will help us find and fix improper uses, and should be removed once
        // all those uses have been found and fixed
        if (newPath.StartsWith(root))
        {
            throw new ArgumentException(
                "The path appears to already be fully qualified.  Please remove the call to MapPathWebRoot");
        }

        return Path.Combine(root, newPath.TrimStart(Constants.CharArrays.TildeForwardSlashBackSlash));
    }
}