http/https pages have different canonical URLs

[betzster]

If you have SSL turned on, but don't force redirect, http and https pages will have different URLs. Ideally, I think the canonical URL should always use http unless FORCE_SSL is turned on.

Even a filter for rel_canonical would be better than what we have now. Unhooking and creating your own version of rel_canonical() works, but if multiple plugins do this, you end up with multiple canonical URLs set on every page.

Related: #18660, #14458

[johnbillion]

Note that FORCE_SSL doesn't exist yet. See #28521.

I think this can go hand in hand with #28521. There are too many gotchas if we try to automatically enforce any given scheme on a site. See #29708.

[peterwilsoncc]

30581.1.diff forces the scheme of the rel_canonical URL to match that of the home page defined in options > general.

The current behaviour remains for URLs without the http, https or relative protocols (check is taken from get_home_url).

[newash]

+1 for the filter option, it would be really nice and also non-intrusive.

[joemcgill]

Just ran into this myself. A filter would be nice, but in the mean time, forcing the site to respect the scheme set in the home option as 30581.1.diff​ suggests so the canonical URL doesn't change based on context.

[joemcgill]

Alternately, it looks like the approach in #36168 would be to replace the get_permalink() call with a call to a new function, get_canonical_url().

[SergeyBiryukov]

If you have SSL turned on, but don't force redirect, http and https pages will have different URLs.

Found a related issue: if you have a static home page set, it does force a redirect​. Posts and other pages don't.

[palmiak]

The filter was introduced in wp_get_canonical_url in WP 4.6. I think that adding another filter in rel_canonical would be a duplicate.

[johnbillion]

@joostdevalk Wanna pick this up again in 5.3?

[joostdevalk]

Is there a way for us to detect that https is "working" for a site? Because if so all our canonicals should always be https.