Action: Navigation

Status: Implemented, work in progress
version: 0.3 (see repo)

Scroll to the previous or next page
Navigate between predefined pages / chapters

chapter navigation

For display at the top and bottom of the page.

Static or dynamic, formatter or action.

The very moment it loads metadata like the page title via the page tag its dynamic.

{{navigation
  prev="ChapterOne"
  next="ChapterTwo"
  main="Overview"
}}

1. Determination of pages and context

cluster
- how to define the order
- subset of pages
predefined array, pages="Page1, Page2, Page3, ..."
- this can also be a custom menu
via parameter prev="PreviousPage", next="NextPage" and main="MainPage"

It is possible to define the navigation on every single page or include a dedicated section as page with dynamic determination.

2. Options

noinclude
- , 
layout
- table=1|0
style
link text
- page title - title=1
- default
- custom

CSS

no-print

3. Action

3.1. via link()

source:master/src/action/navigation.php

<?php

if (!defined('IN_WACKO'))
{
    exit;
}

/* navigation action:
 *
 *
TODO:
    - add option to choose custom menu as data source
*/

$info = <<<EOD
Description:
    Generates navigation bars to navigate between chapters of a book.

Usage:
    {{navigation}}

Options:
    [main="Overview"]
        tag of overview
    [prev="PreviousPage"]
        tag of previous chapter
    [next="NextPage"]
        tag of next chapter
    [title=0|1]
        uses page title for links
EOD;

// set defaults
$help        ??= 0;
$main        ??= '';
$next        ??= '';
$prev        ??= '';
$table        ??= 1;
$title        ??= 0;
$track        ??= true; // seems to have no effect


if ($help)
{
    $tpl->help    = $this->help($info, 'navigation');
    return;
}

// resolve relative tag
$_main    = $this->unwrap_link($main);
$_next    = $this->unwrap_link($next);
$_prev    = $this->unwrap_link($prev);

// preload link data
$pages    = [$_prev, $_main, $_next];

foreach ($pages as $page)
{
    if ($page != '')
    {
        $q_spages[]        = $this->db->q($page);
    }
}

$pages = $this->db->load_all(
    'SELECT ' . $this->page_meta . ' ' .
    'FROM ' . $this->prefix . 'page ' .
    'WHERE tag IN ( ' . implode(', ', $q_spages) . ' ) '
    , true);

$__main    = null;
$__next    = null;
$__prev    = null;

foreach ($pages as $page)
{
    $this->cache_page($page, true);
    $page_ids[]    = $page['page_id'];
    $this->page_id_cache[$page['tag']] = $page['page_id'];

    if ($page['tag'] == $_prev)
    {
        $__prev = $page;
    }
    if ($page['tag'] == $_main)
    {
        $__main = $page;
    }
    if ($page['tag'] == $_next)
    {
        $__next = $page;
    }
}

// cache acls
$this->preload_acl($page_ids, ['read']);

// fall back to tag
if (!$__prev)
{
    $__prev['tag']        = $_prev;
    $__prev['title']    = '';
}
if (!$__main)
{
    $__main['tag']        = $_main;
    $__main['title']    = '';
}
if (!$__next)
{
    $__next['tag']        = $_next;
    $__next['title']    = '';
}

// link text
$__main['text'] = '↑ ' .    ($title ? $__main['title'] : $this->_t('Overview'));
$__prev['text'] = '« ' .    ($title ? $__prev['title'] : $this->_t('Back'));
$__next['text'] =            ($title ? $__next['title'] : $this->_t('Next'))        . ' »';

$__main['title'] = ($title ? '' : $__main['title']);
$__prev['title'] = ($title ? '' : $__prev['title']);
$__next['title'] = ($title ? '' : $__next['title']);

// define navigation links
$tpl->enter($table ? 'tbl_' : 'div_');
$tpl->main_link            = $this->link('/' . $__main['tag'], '', $__main['text'], $__main['title'], $track, true, false);

if ($prev)
{
    $tpl->prev_link        = $this->link('/' . $__prev['tag'], '', $__prev['text'], $__prev['title'], $track, true, false);
}

if ($next)
{
    $tpl->next_link        = $this->link('/' . $__next['tag'], '', $__next['text'], $__next['title'], $track, true, false);
}

if ($prev & $next)
{
    $tpl->separator    = true;
}

$tpl->leave();

3.2. via href()

static, no metadata lookup

<?php

if (!defined('IN_WACKO'))
{
    exit;
}

/* navigation action:
 *
 *
TODO:
    - add option to choose custom menu as data source
*/

$info = <<<EOD
Description:
    Generates navigation bars to navigate between chapters of a book.

Usage:
    {{navigation}}

Options:
    [main="Overview"]
        tag of overview
    [prev="PreviousPage"]
        tag of previous chapter
    [next="NextPage"]
        tag of next chapter
EOD;

// set defaults
$help            ??= 0;
$main            ??= '';
$next            ??= '';
$prev            ??= '';

if ($help)
{
    $tpl->help    = $this->help($info, 'navigation');
    return;
}


$tpl->enter('table_');
$tpl->main_href        = $this->href('', $this->unwrap_link($main));
$tpl->prev_href        = $this->href('', $this->unwrap_link($prev));
$tpl->next_href        = $this->href('', $this->unwrap_link($next));
$tpl->leave();

4. Template

The main goal is to have a customizable standard template for scrolling between pages.

« Previous	Content	Next »
← Back to overview		« Back \| Next »

The content section even could hold a drop down or fly-out menu with all available pages / chapters.
The next and previous button should show the page title via title="Chapter Two" of the page.
The link text can be set individually.

prev, previous, Previous Chapter, back
next, Next Chapter, forward
Overview, Index, Content
page title, page_tag
custom link text
«, », ↑, ←, →

source:master/src/action/template/navigation.tpl

[ === main === ]
<!--noinclude-->
	[ ' help ' ] 
	<nav class="nav-chapter no-print">
	[= tbl _ =
		<table>
			<tr>
				<td>
				[= prev _ =
					[ ' link ' ]
				=]
				</td>
				<td>
				[= main _ =
					[ ' link ' ]
				=]
				</td>
				<td>
				[= next _ =
					[ ' link ' ]
				=]
				</td>
			</tr>
		</table>
	=]
	[= div _ =
		[= main _ =
			[ ' link ' ]
		=]
		<div class="pagination">
		[= prev _ =
			[ ' link ' ]
		=]
		[= separator _ =
			[ ' nonstatic ' ]
		 | 
		=]
		[= next _ =
			[ ' link ' ]
		=]
		</div>
	=]
	</nav>
<!--/noinclude-->

[ === main === ]
<!--noinclude-->
	[ ' help ' ] 
	<nav class="nav-capter no-print">
	[= table _ =
		<table>
			<tr>
				<td>
				[= prev _ =
					<a href="[ ' href ' ]">« [ ' _t: Back ' ]</a>
				=]
				</td>
				<td>
				[= main _ =
					<a href="[ ' href ' ]">↑ [ ' _t: Overview ' ]</a>
				=]
				</td>
				<td>
				[= next _ =
					<a href="[ ' href ' ]">[ ' _t: Next ' ] »</a>
				=]
				</td>
			</tr>
		</table>
	=]
	[= div _ =
		<div class="nav-capter">

		</div>
	=]
	</nav>
<!--/noinclude-->

4.1. CSS

add to default.css

/* navigation action ------------- */
.nav-chapter {
	background-color: rgb(241, 241, 241);
	padding: 10px 10px;
}
.nav-chapter td:nth-child(1) {
	text-align:left;
	white-space: nowrap;
}
.nav-chapter td:nth-child(2) {
	text-align: center;
width: 100%;
}
.nav-chapter td:nth-child(3) {
	text-align:right;
	white-space: nowrap;
}

5. ToDo

workout of details

track links (?)
add option for alternate layout: table=1|0 (table|div layout)
add option for alternate link text
- alternate standard text or combination
- via parameter, e.g.
  - prev_text="Custom link text"
  - via delimiter after the tag prev="ChapterOne|First Chapter"
  - title=1 - uses page title
- via sub template
add option to choose custom menu as data source
simplify and refactor draft
naming and wording
print handler displays links for hidden action

Add a good enough version (that will do for most cases) to the core, add some examples here for more advanced templates for copy and paste.

6. Example

/Book/ChapterOne

{{navigation main="/Book" next="ChapterTwo"}}

/Book/ChapterTwo

{{navigation main="/Book" prev="ChapterOne" next="ChapterThree"}}

/Book/ChapterThree

{{navigation 
  main="/Book" 
  prev="ChapterTwo" 
  next="ChapterFour"
  title=1
}}

7. Changelog

0.1 Intitial version
0.2 adds nav-chapter class to CSS and message set for 'Overview'
0.3 adds parameter title=0|1, shows page title as link text

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