Support multisite with subdirectories in navigate function

[SantosGuillamot]

As reported here, some sites use a subdirectory, so using a relative path in the navigate function won't work as expected. Imagine I have a multisite in mysite.com/en/. If I call navigate("/"), it will navigate to mysite.com instead of mysite.com/en/.

Not sure what is the best way to handle this, but I assume the navigate function should be aware of this somehow. Should we expose the site URL in the store as discussed here? Should we populate the site URL in the SSR using the get_site_url() function?

[luisherranz]

Can we rely on the <base> element? Is it always present in WordPress? If not, maybe we should populate state.router.base?

[SantosGuillamot]

Can we rely on the element? Is it always present in WordPress?

I think we can't rely on the <base> tag. I've checked a bunch of WordPress sites, and none of them had it.

If not, maybe we should populate state.router.base?

That was my initial idea. I guess it will be helpful in more use cases.

What I am not sure about is if this should be populated from the server using the get_site_url() function or somehow in the client. Or maybe both? If state.router.base doesn't exist, populate it with window.location.origin or something similar. I'm thinking in edge cases where this is used outside of WordPress, and that function is unavailable.

[luisherranz]

I think you can't get it reliably from window.location, can you? I.e., imagine that you land at https://site.com/a/b/c. There's no way to know if WordPress is installed in /, /a or /a/b.

[SantosGuillamot]

I think you can't get it reliably from window.location, can you? I.e., imagine that you land at https://site.com/a/b/c. There's no way to know if WordPress is installed in /, /a or /a/b.

Yes, I think you can't. That's why I suggested using it as a fallback in case it is not defined from the server.

[westonruter]

I don't think get_site_url() is quite right since it is where WordPress is installed, not what the actual site address is. The site address is the home URL returned by get_home_url(). I suppose outputting that in a custom meta tag is what is needed. Alternatively, a rel-home microformat could be used (which doesn't seem fully standardized, but it does have modest usage).

add_action( 'wp_head', function () {
   printf( '<link rel="home" href="%s">', esc_url( get_home_url() ) ); 
} );