How to fix incorrect AIOSEO canonical URLs in a subdirectory WP

2022-03-26 2022-06-09

Here's how to fix the issue where the canonical URL output by All in One SEO is duplicated on a WordPress site installed in a subdirectory.

Specifically

On a WordPress site installed under /blog/

The canonical tag sometimes looked like this:

<link rel="canonical" href="https://example.com/blog/blog/">

Subpages looked like this:

<link rel="canonical" href="https://example.com/blog/blog/?p=00000">

There was no such item in the AIOSEO settings screen,
and changing these settings seemed like it would resolve it, but

Site Address in General Settings

Conclusion

We will use a filter hook.

Add this to functions.php.

//AIOSEO Canonical URL Normalization Filter Hook
add_filter( 'aioseo_canonical_url', 'aioseo_filter_canonical_url');
function aioseo_filter_canonical_url($url){
	if(strpos($url, '/blog/blog/')){ //'/blog/blog/'が含まれる時
		$result = str_replace('/blog/blog/', '/blog/', $url); //'/blog/'に置き換える
		return $result;
	}else{
		return $url;
	}
}

Using the aioseo_canonical_url filter hook,

when the string "/blog/blog/" is present, it is replaced with "/blog/".

The official documentation is here:

aioseo_canonical_url - AIOSEO