Test for rel=canonical the same as a redirect

[fulldecent]

Currently we test for redirects. So we can mark as an error if you are linking to a page that has a redirect. That's good.

A redirect can be implemented by using HTTP or putting it in the HTML meta.

But I also consider a rel=canonical as a redirect if the page you are accessing is not the canonical URL. This is because GitHub Pages (and maybe some other static web hosts) don't let you set redirects and your page is accessible as extensionless (preferred) as well as .html. If the canonical one is extensionless and you are linking to .html that should be detectable as an error.

[gjtorikian]

Can you point me to a real-life website with rel="canonical" so that I can see the behavior of how a browser or curl handles these situations?

[fulldecent]

Browsers and cURL do not do anything special with this.

Basically only search engines will use this URL as a hint for giving other pages preference in listings.

Definition at https://html.spec.whatwg.org/#link-type-canonical

[gjtorikian]

Gotcha, thanks