Pagination with rel=next and rel=prev WordPress

cor comments:

Hello Francisco,

That's OK. Normally I don't mind (also being Dutch myself).
I have some difficulties though understanding your code. Could you tell what it exactly does? (I assume you've read the Google article I've linked to?)

Francisco Javier Carazo Gil comments:

Hi Cor,

This method is an implementation for: http://googlewebmastercentral.blogspot.com/2011/09/pagination-with-relnext-and-relprev.html in WordPress.

Exactly, this function obtains a complete pagination if we are in home, in a category or in a tag.

Then it splits previous and next URL of current page, to insert it in HTML header into "link" tag with his attribute: "rel = prev/next".

I'm going to translate vars to English to help understanding. I have solved also an error.


<?php
function next_prev()
{
global $wp_query;

$top_level = 999999999;
$complete_pagination = paginate_links(
array(
'base' => str_replace( $top_level, '%#%', get_pagenum_link( $top_level ) ),
'format' => '?paged=%#%',
'current' => max( 1, get_query_var('paged') ),
'total' =>$wp_query->max_num_pages)
);

$array_pagination=explode("</a>",$complete_pagination);

foreach ($array_pagination as $link)
{
if (strrpos($link,"Next"))
{
preg_match('(http://"?.*")',$link,$matches,PREG_OFFSET_CAPTURE,3);
$next = explode('"',$matches[0][0]);
echo "<link rel=\"next\" href=\"" . $next[0] . "\"/>\n";
}
if (strrpos($link,"Previous"))
{
preg_match('(http://"?.*")',$link,$matches,PREG_OFFSET_CAPTURE,3);
$previous = explode('"',$matches[0][0]);
echo "<link rel=\"prev\" href=\"".$previous[0]."\"/>\n";
}
}
}
?>


cor comments:

Hi Francisco,

It's kind of weird. It's working here klanten.24design.net/html5/, but somehow isn't working here erodesign.net/.

Both installs are pretty much default.

Do you know what might be causing this perhaps?

Francisco Javier Carazo Gil comments:

Yes, it's really strange. Try to set WP_DEBUG to true and also switch on the error reporting in PHP:

error_reporting(E_ALL);
ini_set('display_errors','On');


Francisco Javier Carazo Gil comments:

Sorry, I have answered before I finished.

Tell me if there are any error. If no error, maybe some filter is giving some incompatibility.

cor comments:

Hi Francisco,

I should have realized this sooner, but the only difference between those site was its localization.

I've also renamed some vars back to match the codex (I tend to Google my code in case I forget things :))

Here's the final result:
/**
* http://googlewebmastercentral.blogspot.com/2011/09/pagination-with-relnext-and-relprev.html
*/
function rel_next_prev_pagination() {
global $wp_query;
$big = 999999999; // need an unlikely integer
$paginate_links = paginate_links(array(
'base' => str_replace($big, '%#%', get_pagenum_link($big)),
'format' => '?paged=%#%',
'current' => max(1, get_query_var('paged')),
'total' => $wp_query->max_num_pages
));
$array_pagination = explode("</a>", $paginate_links);
foreach ($array_pagination as $link) {
if (strrpos($link, __('Next &raquo;'))) {
preg_match('(http://"?.*")', $link, $matches, PREG_OFFSET_CAPTURE, 3);
$next = explode('"', $matches[0][0]);
echo "<link rel=\"next\" href=\"" . $next[0] . "\">\n";
}
if (strrpos($link, __('&laquo; Previous'))) {
preg_match('(http://"?.*")', $link, $matches, PREG_OFFSET_CAPTURE, 3);
$previous = explode('"', $matches[0][0]);
echo "<link rel=\"prev\" href=\"" . $previous[0] . "\">\n";
}
}
}
add_action('wp_head', 'rel_next_prev_pagination');

Thanks again!