custom.php

<?php
require_once dirname(__FILE__) . '/functions.php';

add_filter(
    array('ElementForm', 'Item', 'Dublin Core', 'Description'),
    'filter_contribution_description'
);

add_filter(
    array('ElementForm', 'Item', 'Dublin Core', 'Title'),
    'filter_contribution_title'
);

add_filter(
    array('ElementForm', 'Item', 'Item Type Metadata', 'Text'),
    'filter_contribution_text'
);

add_filter(
    array('ElementForm', 'Item', 'Dublin Core', 'Date'),
    'filter_contribution_date'
);

add_filter(
    array('ElementForm', 'Item', 'Dublin Core', 'Spatial Coverage'),
    'filter_contribution_coverage'
);

add_filter(
    array('ElementForm', 'Item', 'Dublin Core', 'Contributor'),
    'filter_contribution_contributor'
);

add_filter(
    array('ElementForm', 'Item', 'Dublin Core', 'Abstract'),
    'filter_contribution_abstract'
);

add_filter(
    array('ElementForm', 'Item', 'Dublin Core', 'Creator'),
    'filter_contribution_creator'
);

add_filter(
    array('Display','Item','Dublin Core', 'Creator'),
    'filter_for_anonymity'
);

add_filter(
    array('Display','Item','Dublin Core', 'Contributor'),
    'filter_for_anonymity'
);

add_filter(
    'item_citation',
    'filter_item_citation'
);

//Retaining sort or search order when paging through items
function custom_paging()
{
//Starts a conditional statement that determines a search has been run
    if (isset($_SERVER['QUERY_STRING'])) {

        // Sets the current item ID to the variable $current
        $current = metadata('item', 'id');

        //Break the query into an array
        parse_str($_SERVER['QUERY_STRING'], $queryarray);

        //Items don't need the page level
        unset($queryarray['page']);

        $itemIds = array();
        $list = array();
        if (isset($queryarray['query'])) {
                //We only want to browse previous and next for Items
                $queryarray['record_types'] = array('Item');
                //Get an array of the texts from the query.
                $textlist = get_db()->getTable('SearchText')->findBy($queryarray);
                //Loop through the texts ans populate the ids and records.
                foreach ($textlist as $value) {
                        $itemIds[] = $value->record_id;
                        $record = get_record_by_id($value['record_type'], $value['record_id']);
                        $list[] = $record;
                }
        }
        elseif (isset($queryarray['advanced'])) {
                if (!array_key_exists('sort_field', $queryarray))
                {
                        $queryarray['sort_field'] = 'added';
                        $queryarray['sort_dir'] = 'd';
                }
                //Get an array of the items from the query.
                $list = get_db()->getTable('Item')->findBy($queryarray);
                foreach ($list as $value) {
                        $itemIds[] = $value->id;
                        $list[] = $value;
                }
        }
        //Browsing all items in general
        else
        {
                if (!array_key_exists('sort_field', $queryarray))
                {
                        $queryarray['sort_field'] = 'added';
                        $queryarray['sort_dir'] = 'd';
                }
                $list = get_db()->getTable('Item')->findBy($queryarray);
                foreach ($list as $value) {
                        $itemIds[] = $value->id;
                }
        }

        //Update the query string without the page and with the sort_fields
        $updatedquery = http_build_query($queryarray);
        $updatedquery = preg_replace('/%5B[0-9]+%5D/simU', '%5B%5D', $updatedquery);

        // Find where we currently are in the result set
        $key = array_search($current, $itemIds);

        // If we aren't at the beginning, print a Previous link
        if ($key > 0) {
            $previousItem = $list[$key - 1];
            $previousUrl = record_url($previousItem, 'show') . '?' . $updatedquery;
                $text = __('&larr; Previous Item');
            echo '<li id="previous-item" class="previous"><a href="' . html_escape($previousUrl) . '">' . $text . '</a></li>';
        }

        // If we aren't at the end, print a Next link
        if ($key >= 0 && $key < (count($list) - 1)) {
            $nextItem = $list[$key + 1];
            $nextUrl = record_url($nextItem, 'show') . '?' . $updatedquery;
                $text = __("Next Item &rarr;");
                echo '<li id="next-item" class="next"><a href="' . html_escape($nextUrl) . '">' . $text . '</a></li>';
        }
    } else {
        // If a search was not run, then the normal next/previous navigation is displayed.
        echo '<li id="previous-item" class="previous">'.link_to_previous_item_show().'</li>';
        echo '<li id="next-item" class="next">'.link_to_next_item_show().'</li>';
    }
}