Configure redirects

---
title: Old page URL
description: Redirects away to the new location.
redirectUrl: /main/front-matter/
order: 200
uid: kitchen-sink.main.redirect-source
---
  
# This page has moved
  
A visit to this URL is intercepted by the Pennington redirect middleware
and returns HTTP 301 with a meta-refresh body pointing at `redirectUrl`.
The static build captures the same 301 and writes the meta-refresh file
to disk at this page's output path — one code path for dev and publish.

/// <summary>
/// Front matter bound by <see cref="DocSiteServiceExtensions.AddDocSite"/>. Extends the
/// <see cref="FrontMatter.DocFrontMatter"/> shape with <see cref="RedirectUrl"/> via
/// <see cref="IRedirectable"/>. Implements <see cref="IFrontMatter"/>, <see cref="ITaggable"/>,
/// <see cref="ISectionable"/>, <see cref="IOrderable"/>, and <see cref="IRedirectable"/>.
/// </summary>
public record DocSiteFrontMatter : IFrontMatter, ITaggable,
    ISectionable, IOrderable, IRedirectable
{
    /// <summary>Page title rendered in the browser tab and page heading.</summary>
    public string Title { get; init; } = "";
  
    /// <summary>Short description used for the meta description and social cards.</summary>
    public string? Description { get; init; }
  
    /// <summary>When true, the page is skipped during production builds.</summary>
    public bool IsDraft { get; init; }
  
    /// <summary>Tags applied to this page for filtering and the tag index.</summary>
    public string[] Tags { get; init; } = [];
  
    /// <summary>Sort order within the containing section. Lower values appear first.</summary>
    public int Order { get; init; } = int.MaxValue;
  
    /// <summary>When set, the page emits a client-side redirect to this URL instead of normal content.</summary>
    public string? RedirectUrl { get; init; }
  
    /// <summary>Section heading this page belongs under in navigation.</summary>
    public string? SectionLabel { get; init; }
  
    /// <summary>Stable identifier used for cross-references (<c>[text](xref:uid)</c>).</summary>
    public string? Uid { get; init; }
  
    /// <summary>When false, the page is excluded from the search index.</summary>
    public bool Search { get; init; } = true;
  
    /// <summary>When false, the page is excluded from the generated llms.txt output.</summary>
    public bool Llms { get; init; } = true;
}

/// <summary>
/// Content that can redirect to another URL.
/// </summary>
public interface IRedirectable
{
    /// <summary>Target URL when this page should redirect; <c>null</c> or empty means no redirect.</summary>
    string? RedirectUrl { get; }
}

/// <inheritdoc/>
public async IAsyncEnumerable<DiscoveredItem> DiscoverAsync()
{
    foreach (var (route, sourceFile) in DiscoverRoutesWithFallbacks())
    {
        TFrontMatter? frontMatter = default;
        try
        {
            var content = await _fileSystem.File.ReadAllTextAsync(sourceFile.Value);
            var parsed = _parser.Parse<TFrontMatter>(content);
            if (parsed.Metadata is { IsDraft: true })
                continue;
            frontMatter = parsed.Metadata;
        }
        catch
        {
            // If front matter can't be parsed, include the file as a markdown source.
        }
  
        // Pages with RedirectUrl front matter are surfaced as RedirectSource so the
        // unified redirect middleware handles them at dev time and the static build
        // crawler captures the 301 response (written as a meta-refresh HTML file).
        if (frontMatter is IRedirectable { RedirectUrl: { Length: > 0 } redirectTarget })
        {
            yield return new DiscoveredItem(route, new RedirectSource(new UrlPath(redirectTarget)));
            continue;
        }
  
        yield return new DiscoveredItem(route, new MarkdownFileSource(sourceFile));
    }
}

dotnet run --project src/YourDocSite