Canonical Links Best Practice

[markhildreth]

Is there a recommended practice for ensuring canonical URLs for a book? For example, the current rust book can be found at these URLs:

• https://doc.rust-lang.org/book/
• https://doc.rust-lang.org/book
  • which 302s to /doc/stable/book/ and then /stable/book/.
• https://doc.rust-lang.org/book/index.html
• https://doc.rust-lang.org/book/title-page.html (although this one is slightly different, in that the title page section in the ToC is styled as "active").

However, I don't notice a <link rel="canonical" href="https://doc.rust-lang.org/book/"> on any of the resulting documents. Should mdbook offer any recommendations in this regard, and/or a configuration option to allow for a canonical link on pages?

[ehuss]

I think it would probably use useful to have a canonical link. Would probably need to add a site-url to the config to specify the canonical URL. Would then need to feed that into the template (perhaps a computed value of site-url joined with the current page's canonical name).

(Note, also briefly discussed adding site-url at #1221 (comment))

[markhildreth]

@ehuss Thanks for the quick response. Based on your response and some more digging, I see a few ways forward:

1.) Expose the rendered path (e.g., /index.html for the root/README.md) to the template. This is technically all we need: then the user could just create the full URL in their template with the rendered path. Something like....

<link rel="canonical" href="https://example.com{{ rendered_path }}" />

A bit hackish (especially with the "who is supposed to add the slash" confusion), but it works.

2.) In addition to the above, expose a canonical-url option (e.g., "https://example.com"). If this option is specified, then all pages will have the canonical link placed in their header by default, created by adding the rendered path onto the given canonical URL.

You mention a site-url, although I'm not sure that's what we want. For example, you may want to have a latest.example.com and an example.com. These might have different site-url values, but for SEO reasons might want to have the same canonical URL.

[pinage404]

Hello,

I changed the domain name of a website generated by mdBook

Now, Google doesn't want to index the new URL because it is detected as duplicate content

Duplicate without user-selected canonical
These pages aren't indexed or served on Google

Is there currently a solution ? (Even if it's a bit hacky)