Explanation and workaround for error 404 on category pagination

This is AWESOME. your function also worked for me.

I had tinkered with this for a while and had NO idea what the deal was, just figured I was not writing the custom TPL properly.
What I started doing was simply setting the max posts per page under WP->settings->reading to simply be “1” and then controlling everything via my template. an unfortunate thing, but just dropping in a custom [homepage] [postpage] on the appropriate page and then building my own loop has worked well for me.

Had no idea why, but now I know! ??

Happy to hear it has been useful to you!

Setting the pagination to “1” in the reading settings is the simplest and most immediate working solution I’ve found to this problem, but then you have to set a value for pagination every time you create a new taxonomy/term/cpt etc, and then you have to “scatter” the pagination-setting on several template files.

My function just groups those settings in one point and allow you to use the value defined in the backend as the default value for every new type of archive/listing.

Aside from wondering why that problem has not been patched yet, I’d like to find the time to use the function above to create a plugin and so integrate the backend reading settings with a list all paginable items and their specific settings. Maybe in a near future…

Hi,
now I know why my pagination doesn’t work … I tried your workaround, no more 404 error but it don’t work correctly ??
I have 3 categories with differents “posts_per_page” 6, 2 and 8
Now I have this problem : I click on next news page (posts_per_page==2) => go category/news/page/2/ and it always display posts 1 to 2 and not 3 to 4
the same with other categories
<?php query_posts('cat=3&posts_per_page=2&paged=' . get_query_var('paged')); ?>
I test on v3.3.1

@ch0usse
If you are using my function “cure_wp_amnesia_on_query_string” (with your category slugs and values, of course), you no longer have to alter the query vars adding &post_per_page=x&paged=etc etc. They are automagically added every time WP needs to know their values.

As I wrote above, with this function, you no longer have to “scatter” the pagination-settings on several template files.
My function just groups those settings in one point and allow you to use the value defined in the backend as the default value for every new type of archive/listing.

If it doesn’t work, try to post here (or on pastebin.com) the code you are using in your theme function and templates.

Bye

@mad_max
finally it work ! special thanks but I modified a little bit :

if ( isset( $query_string['cat'] ) ) {
			switch ($query_string['cat']) {
				case 1:
				$query_string['posts_per_page'] = 2;
					break;
				case 5:
				$query_string['posts_per_page'] = 8;
					break;
				case 3:
				$query_string['posts_per_page'] = 6;
				// default:
					// $query_string['posts_per_page'] = 6;
					break;
			}
		}

because WP don’t recognize ‘category_name’, maybe because I don’t use permalinks with localhost.

THX

You are right. I usually use permalinks so this problem has never come to my mind! I think it worths a rewrite of the function to take in account your use case.
Taking out cat names/values from the function and grouping them in a “pagination settings” section of the function.php files (clearly a plugin with an admin page should be the best solution), we can rewrite the code like this:

Permalinks enabled

//POSTS PER PAGE (permalinks on)
$my_ppp =array(
	'category' => array(
		'cat1_name' => X,
		'cat2_name' => Y,
		'cat3_name' => Z,
	),
	'search' => K,
);

Permalinks disabled

//POSTS PER PAGE (permalinks OFF)
$my_ppp =array(
	'category' => array(
		'cat1_ID' => X,
		'cat2_ID' => Y,
		'cat3_ID' => Z,
	),
	'search' => K,
);

And then the function:

if ( isset( $my_ppp ) && is_array( $my_ppp ) && count( $my_ppp ) ) add_filter('request', 'cure_wp_amnesia_on_query_string');
function cure_wp_amnesia_on_query_string($query_string){
	global $my_ppp;
	if ( !is_admin() ){
		if ( isset( $my_ppp['category'] ) && is_array( $my_ppp['category'] ) )  {
			if ( isset( $query_string['category_name'] ) ) {
				foreach ( $my_ppp['category'] as $category_name => $ppp ) {
					if ( $query_string['category_name'] == $category_name ) {
						$query_string['posts_per_page'] = $ppp;
						break;
					}
				}
			}elseif ( isset( $query_string['cat'] ) ){
				foreach ( $my_ppp['category'] as $cat_id => $ppp ) {
					if ( $query_string['cat'] == $cat_id ) {
						$query_string['posts_per_page'] = $ppp;
						break;
					}
				}
			}
		}
		if ( isset( $my_ppp['search'] ) && isset( $query_string['s'] ) )  {
			$query_string['posts_per_page'] = $my_ppp['search'];
		}
	}
	return $query_string;
}

Works great!

And if you need to modify your queries, you can do it adding parameters to the $query_string array in cure_wp_amnesia_on_query_string function, not in the posts templates.

Brilliant, mate – thanks.

My situation is somewhat less complicated so I used the info on the following page to just reset the main query to 10 posts per page after setting the back end to 1 post per page. This seems to have solved all of my problems (well, related to this specific issue of course ;).

https://www.billerickson.net/customize-the-wordpress-query/

My apologies, but my solution above did not fix my problem. Setting the main query to 10 posts per page in functions.php caused the same problem as setting it in the back end.

Didn’t want anyone else to be confused by this.

AWSM.

@daniele : Thank Bro… you are AWESOMEE.. that fix my problem..

Man, i’ll be forever in debt. What a silly mistake that was, i could’ve lost some precious hours in it without this. Thanks!!

Happy to hear that from all you guys! Hope to find some spare time to code this in a plugin, or better find that the last WP versione has resolved this issue (Hope springs eternal!).