Introduce an X-Redirect-By header

[joostdevalk]

Diagnosing redirect loops can often be very confusing because many parts of a system can perform a redirect. The introduction of the X-Redirect-By header would allow the application to be identified more easily.

Yoast SEO already sends this header and we've found it to be very useful many a time, at nearly no overhead.

[joostdevalk]

Patch

[joostdevalk]

Patch v2

[joostdevalk]

Patch v3, check return value for filter

[SergeyBiryukov]

In 42408:

Canonical: Introduce x_redirect_by filter that allows applications to identify themselves via X-Redirect-By header when they're doing a redirect.

Props joostdevalk.
Fixes #42313.

[SergeyBiryukov]

In 42409:

Canonical: After [42408], remove sprintf() call for consistency with Location header.

See #42313.

[johnbillion]

I really like the idea of this header, but I think we can make the implementation even better.

If the header value could be passed as a parameter in addition to via a filter, it would save the need to call add_filter() immediately before calling the redirect function.

Thoughts?

[NathanAtmoz]

Add $x_redirect_by parameter to wp_redirect()

[NathanAtmoz]

Since the $status can be passed as a parameter and then modified by a filter, it makes sense that $x_redirect_by should be treated the same way.

[SergeyBiryukov]

In 42633:

Canonical: Add $x_redirect_by parameter to wp_redirect() that allows applications doing the redirect to identify themselves.

This complements the x_redirect_by filter added in [42408].

Props NathanAtmoz, johnbillion.
Fixes #42313.

[johnbillion]

The parameter needs adding to wp_safe_redirect() too.

[johnbillion]

In 42647:

Canonical: Add $x_redirect_by parameter to wp_safe_redirect().

See [42633] and [42408].

Fixes #42313.

[johnbillion]

@since needs updating

[pratikkry]

@since updated to 5.0.3

[audrasjb]

Hi,

5.0.3 is going to be released in a couple of weeks. We are currently sorting the remaining tickets in the milestone. The ticket is sorted in milestone 5.0.3, but requires @since and a commit/backport to the associated branch. That would be great to have a quick refresh.

[audrasjb]

@pratikkry thanks for the refresh but the patch you sent seems incomplete ;-)

[audrasjb]

Ok sorry @pratikkry I was wrong, your patch is ok.

[desrosj]

In 44386:

Docs: Update since tag for X-Redirect-By header additions.

See [42408-42409], [42633], [42647].

Fixes #42313.