pn_nid

Roadmap

23 JUL 2013
This module now contains an submodule: Previous Next Field that provides a highly configurable Previous/Next field type. It is working, but needs quite a bit of work still. Right now the biggest roadblock is that I'm not sure if fields require some sort of DB storage or not (currently wading through the API docs). I'm storing "1" for each instance of this field currently, but that's not necessary; each instance of the field is identical. Perhaps it would be useful to store the actual previous next value in the field, but that kind of defeats the purpose of the original parent module's caching mechanism. And I still thing the original module is useful as a standalone.

Previous / Next Node ID

This module provides a function that retrives the previous and/or next Node ID
in a sequence as defined in a list of options passed as a param to the function
sorted by Node ID, Node Title, Published or Changed date. The queries used to
generate this sequence can be slow so this module also creates a table for
storage and quick retrieval of the values.

Sequences can be restricted by node status, node type and taxonomy terms.

USAGE

The following function is available after enabling the module:

  pn_nid($nid, $op = 'next', $sort = SORT_NID, $options = array('types' => FALSE, 'terms' => FALSE, 'unpublished' => FALSE));

Examples

Return the next published node after Node ID 100 of any content type:

  pn_nid(100);
  // Returns `101` If nid 101 exists and is published.

Return the previous published node before Node 100 of any content type:

  pn_nid(100, 'prev');
  // Returns `99` If nid 99 exists and is published.

Return the next node ofter Node ID 100 that is published and an `article` or
`page` content type:

  pn_nid(100, 'next', array('types' => array('article', 'page')));
  // Returns `101` If nid 101 exists, is published and is either a page or
  // article.

Return the next node ofter Node ID 100 that is an `article` or `page` content
type regardless of whether or not it is published:

  pn_nid(100, 'next', array('types' => array('article', 'page'), 'unpublished' => TRUE))

Return the next node after Node 100 sorted alphabetically.

  pn_nid(100, 'next', SORT_ALPHA);

DATABASE STORAGE

By default, the Previous/Next cache is cleared each time a node is created/
saved/deleted. This is appropriate for most sites because doing so can affect
the next or previous node in a given sequence.

You can also choose to have the cache emptied on cron or turn off automatic
cache clearing entirely.

SORTING

The third parameter controls how the sequence is sorted and accepts one
the following named constants:

* **SORT_NID** (default)
> Sorts the results numerically based on Node ID

* **SORT_ALPHA**
> Sorts the results alphabetically based on Node Titles

* **SORT_CREATED**
> Sorts the results based on Node creation dates

* **SORT_CHANGED**
> Sorts the results based on Node last updated dates

SIMILAR MODULES

Previous/Next API provides similar
functionality, but differs from this module in the following significant ways:

1. Previous/Next API builds the entire Previous/Next Node table on cron (or in
batches of 200 nodes at a time) whereas this module doesn't create an entry
until that specific Previous/Next sequence is requested.

2. Previous/Next API limits the administrator to one set of node types to
reuturn. This module allows you to, for example, have a link to the next
node of Content Type A in one template, and a link to the next node of
Content Type B on another.

3. This module allows you to limit Previous/Next results by Taxonomy.