Ambrosite Next/Previous Post Link Plus Plugin

IMPORTANT: Make sure you are using the right plugin.

• Next/Previous Post Link Plus is intended for use in single post templates.
• Next/Previous Page Link Plus is intended for use in page templates.

The two plugins have similar sounding, but different, function names. If you mistakenly install the wrong plugin, you will get a “call to undefined function” error. If you want to create next/previous links for your pages, please check out:
https://wordpress.org/extend/plugins/ambrosite-nextprevious-page-link-plus/

IMPORTANT: This plugin is not compatible with PHP 4. If you try to install it on a host running PHP 4, you will get a parse error. WordPress has officially ended support for PHP 4 as of version 3.2, so you should upgrade to PHP 5.2 now. For those who cannot upgrade, you can download the alternate PHP 4 compatible version of the plugin. The only difference with the PHP 4 version is that the %category variable will not work with custom taxonomies.
http://www.ambrosite.com/download/ambrosite-nextprevious-post-link-plus.php4.zip

This plugin creates two new template tags — next_post_link_plus and previous_post_link_plus — which are upgraded versions of the core WordPress next_post_link and previous_post_link template tags. The new tags include all of the functionality of the core tags, plus the following additional options:

• Sort the next/previous post links on columns other than post_date (e.g. alphabetically).
• Sort next/previous links on custom fields (both string and integer sorts are supported).
• Full WordPress 3.3 compatibility, including support for custom post types, custom taxonomies, and post formats.
• Loop around to the first post if there is no next post (and vice versa).
• Retrieve the first/last post, rather than the previous/next post (for First|Previous|Next|Last navigation links).
• Display post thumbnails alongside the links (WordPress 2.9 or higher).
• Truncate the link titles to any length, and display custom text in the tooltip.
• Display the title, date, author, category, and meta value of the next/previous links.
• Specify a custom date format for the %date variable.
• Restrict next/previous links to same category, taxonomy, format, author, custom field value, custom post ID list, or custom category list.
• Exclude categories, custom taxonomies, post formats, or individual post IDs.
• Three category exclusion methods for greater control over the navigation stream.
• Return multiple next/previous links (e.g. the next N links, in an HTML list).
• Return the ID, title, date, href attribute, or post object of the next/previous links, instead of echoing them to the screen.
• Return false if no next/previous link is found, so themes may conditionally display alternate text.
• Works with Post Types Order and other popular post reordering plugins.

Extensive documentation on configuring the plugin may be found here:
http://www.ambrosite.com/plugins/next-previous-post-link-plus-for-wordpress

• Upload ambrosite-post-link-plus.php to the /wp-content/plugins/ directory.
• Activate the plugin through the Plugins menu in WordPress.
• Edit your template files, and replace the next_post_link and previous_post_link template tags with next_post_link_plus and previous_post_link_plus. Configure them using parameters as explained in the online documentation:
  http://www.ambrosite.com/plugins/next-previous-post-link-plus-for-wordpress

• How exactly do I install this plugin? Which file needs to be edited, and where do I put the code?
• I am getting a parse error while attempting to install the plugin. Why?
• I am getting a “call to undefined function” error. Why?
• How can I get rid of the arrows on my next/previous links?
• I am confused about the difference between strong, differential, and weak exclusion. Which one should I use?
• I am using a custom field with a simple integer value to order my posts, but they’re not sorting correctly. Why?
• I am seeing the number ‘1’ printed next to my links. Why?
• What about compatibility with the Post Types Order plugin?
• What about compatibility with the WPML plugin?
• What about compatibility with the qTranslate plugin?
• Is there any way to use an image instead of link text?

Answers to these questions may be found here:
http://www.ambrosite.com/plugins/next-previous-post-link-plus-for-wordpress#faq

Installation Instructions

• Upload ambrosite-post-link-plus.php to the /wp-content/plugins/ directory.
• Activate the plugin through the Plugins menu in WordPress.
• Edit your template files, and replace the next_post_link and previous_post_link template tags with next_post_link_plus and previous_post_link_plus. Configure them using parameters as explained in the online documentation:
  http://www.ambrosite.com/plugins/next-previous-post-link-plus-for-wordpress

2.4

• Added ‘in_cats’ parameter.
• Added ‘in_same_meta’ parameter.
• Added ‘return’ parameter to specify what should be returned from the function.
• Added ‘date_format’ parameter for customizing the %date variable.
• Added %title variable to ‘format’ parameter.
• Added option to sort on custom fields as integers rather than strings.
• Primary sort column defaults to ‘menu_order’ if Post Types Order plugin is installed.
• Many documentation updates to address frequently asked questions.

2.3

• Added ‘in_same_author’ parameter.
• Added ‘in_posts’ parameter.
• Added ‘post_type’ parameter.
• Added option to specify a custom taxonomy with ‘in_same_tax’.
• Added new format variable (%author).
• Added variables (%title, %date, %author) to custom tooltip text.
• Added option to suppress the tooltip completely.
• Renamed filters for compatibility with Post Types Order and other plugins that attempt to filter the output of get_adjacent_post.

2.2

• Added option to retrieve the first/last post links.
• Added support for post formats.
• Improved support for custom taxonomies.
• Added ‘tooltip’ parameter to specify custom tooltip text.
• Added %meta variable to the format parameter.
• Ground-up rewrite of the ‘ex_cats’ functionality, with three exclusion methods for greater control over the navigation stream.
• Added ‘ex_posts’ parameter to exclude individual post IDs.
• Added option to return the next/previous links as a PHP string.

2.1

• Added ‘order_2nd’ parameter for specifying a secondary sort column.
• Updated the documentation to address PHP 4 incompatibility problems.

2.0

• Full WordPress 3.0 compatibility, including custom post types.
• Rewrote the plugin using wp_parse_args to simplify the function calls.
• Added option to sort the next/previous links on custom fields.
• Added option to return multiple next/previous links.
• Fix for custom taxonomies.
• Added %category variable to the format parameter.
• Added ‘before’ and ‘after’ parameters.
• Added support for post thumbnail sizes.
• Added ‘echo’ parameter.

1.1

• Added truncate link title and loop options.
• Added support for post thumbnails.

1.0

• Initial version.