Use PathBase to support Virtual Directory

[eloekset]

Changes to various components to make use of PathBase for IIS Virtual Directories.

The previous functionality has no unit tests and the changes haven't been thoroughly tested. I.e. no multi-site Piranha application has been tested with the changed framework.

The site template also needs a change to make use of the new feature of the Piranha.AspNetCore package. Menu item links must use WebApp.Url(sitemapItem) to generate correct URLs:

<div class="navbar-collapse collapse" id="mobileNavbar">
        <ul class="justify-content-center navbar-nav mr-auto">

            @foreach (var item in WebApp.Site.Sitemap)
            {
                if (!item.IsHidden)
                {
                    <li class="nav-item @(item.Id == WebApp.PageId || item.HasChild(WebApp.PageId) ? "active" : "")">
                        <a class="nav-link" href="@WebApp.Url(item)">@item.MenuTitle</a>
                    </li>
                }
            }
        </ul>
    </div>

[tidyui]

The SitemapMiddleware should probably be handled differently. Since the IntegratedMiddleware is executed before everything in the RequestHelper should be set. Secondly, it will be more readable if the Sitemap middleware uses the new extension methods for Absolute URLs.

[eloekset]

Thanks for your feedback! 👍
I’ll take another look at it and see if I understand the middleware flow.

[tidyui]

Here you can the order in which the middleware is added!

https://github.com/PiranhaCMS/piranha.core/blob/master/core/Piranha.AspNetCore/AspNetCoreStartupExtensions.cs#L71