[Bug] sitemap contains redirect page entries

[filzrev]

Describe the bug

Sitemap.xml contains redirect page entries.
Redirect page should not be included in sitemap's entry.

To Reproduce

Steps to reproduce the behavior:

1. Gets sitemap.xml content(https://dotnet.github.io/docfx/sitemap.xml)
2. Check redirected page(https://dotnet.github.io/docfx/tutorial/walkthrough/walkthrough_create_a_docfx_project_2.html) exists.

Expected behavior

redirect page is not appear in sitemap entries.

How to fix this problem

It seems SitemapGenerator PostProcessor can't access FileModel metadata directly as described below.

https://dotnet.github.io/docfx/tutorial/howto_add_a_customized_post_processor.html#step3-process-all-the-files-generated-by-docfx

Post-processor aims to process the output files, so the FileModel can't be accessed in this phase. If some metadata is needed here,
an option is to save it in FileModel.ManifestProperties in build phase, then access it through ManifestItem.Metadata.
Another option is to save it somewhere in output files, like HTML's Tag.

---

I want to making modifications in the following directions, but if you have a better idea, please let us know.

1. Add new HtmlPostProcessor handler to check <meta http-equiv="refresh" tag existence. and save metadata to OutputFileInfo.
2. Then SitemapGenerator use this metadata to filter redirect page.

Pros

• No need to modify DocumentProcessors.
• No need to open HTML file at SitemapGenerator.

Cons

• It dependent on a specification that HtmlPostProcessor is executed in first priority
• It dependent on <meta http-equiv="refresh".
  For SEO optimization, redirect may be implemented at server side feature.
  (Example: https://www.statiq.dev/guide/web/content-files/redirects)

[yufeih]

I'd prefer we check redirect_url metadata over <meta http-equiv, as many redirections are implemented server side.

The SitemapGenerator does not have access to metadata, may be we can change the DocumentType of redirections to Redirection instead of Conceptual here?

[filzrev]

Thanks for the reply.

we can change the DocumentType of redirections to Redirection instead of Conceptual

If DocumentType can changed to Redirection.
It'll be a clean and more extensible architecture.

[filzrev]

This issue is fixed by #8892