/ 
HTML-Widgets-NavMenu-0.1.13_00
River stage two • 8 direct dependents • 10 total dependents
/ HTML::Widgets::NavMenu

NAME

HTML::Widgets::NavMenu - A Perl Module for Generating HTML Navigation Menus

SYNOPSIS

use HTML::Widgets::NavMenu;

my $nav_menu =
    HTML::Widgets::NavMenu->new(
        'path_info' => "/me/",
        'current_host' => "default",
        'hosts' =>
        {
            'default' =>
            {
                'base_url' => "http://www.hello.com/"
            },
        },
        'tree_contents' =>
        {
            'host' => "default",
            'value' => "Top 1",
            'title' => "T1 Title",
            'expand_re' => "",
            'subs' =>
            [
                {
                    'value' => "Home",
                    'url' => "",
                },
                {
                    'value' => "About Me",
                    'title' => "About Myself",
                    'url' => "me/",
                },
            ],
        },
    );

my $results = $nav_menu->render();

my $nav_menu_html = join("\n", @{$results->{'html'}});

DESCRIPTION

This module generates a navigation menu for a site. It can also generate a complete site map, a path of leading components, and also keeps track of navigation links ("Next", "Prev", "Up", etc.) It's a little bit scarse on documentation now, because it's still was not made ready for public consumption yet. You can start from the example above and see more examples in the tests, and complete working sites in the Subversion repositories at http://stalker.iguide.co.il:8080/svn/shlomif-homepage/ and http://opensvn.csie.org/perlbegin/perl-begin/.

To use this module call the constructor with the following named arguments:

hosts

This should be a hash reference that maps host-IDs to another hash reference that contains information about the hosts. An HTML::Widgets::NavMenu navigation menu can spread across pages in several hosts, which will link from one to another using relative URLs if possible and fully-qualified (i.e: http://) URLs if not.

Currently the only key present in the hash is the base_url one that points to a string containing the absolute URL to the sub-site. The base URL may have trailing components if it does not reside on the domain's root directory.

Here's an example for a minimal hosts value:

'hosts' =>
{
    'default' =>
    {
        'base_url' => "http://www.hello.com/"
    },
},

And here's a two-hosts value from my personal site, which is spread across two sites:

'hosts' =>
{
    't2' => 
    {
        'base_url' => "http://www.shlomifish.org/",
    },
    'vipe' =>
    {
        'base_url' => "http://vipe.technion.ac.il/~shlomif/",
    },
},
current_host

This parameter indicate which host-ID of the hosts in hosts is the one that the page for which the navigation menu should be generated is. This is important so cross-site and inner-site URLs will be handled correctly.

path_info

This is the path relative to the host's base_url of the currently displayed page. The path should start with a "/"-character, or otherwise a re-direction excpetion will be thrown (this is done to aid in using this module from within CGI scripts).

tree_contents

This item gives the complete tree for the navigation menu. It is a nested Perl data structure, whose syntax is fully explained in the section "The Input Tree of Contents".

ul_classes

This is an optional parameter whose value is a reference to an array that indicates the values of the class="" arguments for the <ul> tags whose depthes are the indexes of the array.

For example, assigning:

'ul_classes' => [ "FirstClass", "second myclass", "3C" ],

Will assign "FirstClass" as the class of the top-most ULs, "second myclass" as the classes of the ULs inner to it, and "3C" as the class of the ULs inner to the latter ULs.

If classes are undef, the UL tag will not contain a class parameter.

A complete invocation of an HTML::Widgets::NavMenu constructor can be found in the SYNOPSIS above.

After you initialize an instance of the navigation menu object, you need to get the results using the render function.

$results = $nav_menu->render()

render() should be called after a navigation menu object is constructed to prepare the results and return them. It returns a hash reference with the following keys:

'html'

This key points to a reference to an array that contains the tags for the HTML. One can join these tags to get the full HTML. It is possible to delimit them with newlines, if one wishes the markup to be easier to read.

'leading_path'

This is a reference to an array of leading path objects. These indicate the intermediate pages in the site that lead from the front page to the current page. The methods supported by the class of these objects is described below under "The Leading Path Component Class".

'nav_links'

This points to a hash reference whose keys are Mozilla-style link-toolbar ( http://cdn.mozdev.org/linkToolbar/ ) link IDs and its values are the URLs to these links.

This sample code renders the links as <link rel=...> into the page header:

my $nav_links = $results->{'nav_links'};
# Sort the keys so their order will be preserved
my @keys = (sort { $a cmp $b } keys(%$nav_links));
foreach my $key (@keys)
{
    my $url = $nav_links->{$key};
    print {$fh} "<link rel=\"$key\" href=\"" .
        CGI::escapeHTML($url) . "\" />\n";
}

$text = $nav_menu->gen_site_map()

This function can be called to generate a site map based on the tree of contents. It returns a scalar containing all the text of the site map.

The Input Tree of Contents

The input tree is a nested Perl data structure that represnets the tree of the site. Each node is respresented as a Perl hash reference, with its sub-nodes contained in an array reference of its 'subs' value. A non-existent 'subs' means that the node is a leaf and has no sub-nodes.

The top-most node is mostly a dummy node, that just serves as the father of all other nodes.

Following is a listing of the possible values inside a node hash and what their respective values mean.

'host'

This is the host-ID of the host as found in the 'hosts' key to the navigation menu object constructor. It implicitly propagates downwards in the tree. (i.e: all nodes of the sub-tree spanning from the node will implicitly have it as their value by default.)

Generally, a host must always be specified and so the first node should specify it.

'url'

This contains the URL of the node within the host. The URL should not contain a leading slash. This value does not propagate further.

The URL should be specified for every nodes except separators and the such.

'value'

This is the text that will be presented to the user as the text of the link inside the navigation bar. E.g.: if 'value' is "Hi There", then the link will look something like this:

<a href="my-url/">Hi There</a>

Or

<b>Hi There</b>

if it's the current page. Not that this text is rendered into HTML as is, and so should be escaped to prevent HTML-injection attacks.

'title'

This is the text of the link tag's title attribute. It is also not processed and so the user of the module, should make sure it is escaped if needed, to prevent HTML-injection attacks. It is optional, and if not specified, no title will be presented.

'subs'

This item, if specified, should point to an array reference containing the sub-nodes of this item, in order.

'separator'

This key if specified and true indicate that the item is a separator, which should just leave a blank line in the HTML. It is best to accompany it with 'skip' (see below).

If 'separator' is specified, it is usually meaningless to specify all other node keys except 'skip'.

'skip'

This key if true, indicates that the node should be skipped when traversing site using the Mozilla navigation links. Instead the navigation will move to the next or previous nodes.

'hide'

This key if true indicates that the item should be part of the site's flow and site map, but not displayed in the navigation menu.

'role'

This indicates a role of an item. It is similar to a CSS class, or to DocBook's "role" attribute, only induces different HTML markup. The vanilla HTML::Widgets::NavMenu does not distinguish between any roles, but see HTML::Widgets::NavMenu::HeaderRole.

'expand_re'

This specifies a regular expression to be matched against the path to determine if the navigation menu should be expanded at this node. If it does, all of the nodes up to it will expand as well.

'show_always'

This value if true, indicates that the node and all nodes below it (until 'show_always' is explicitly set to false) must be always displayed. Its function is similar to 'expand_re' but its propagation semantics the opposite.

The Leading Path Component Class

When retrieving the leading path, an array of objects is returned. This section describes the class of these objects, so one will know how to use them.

Basically, it is an object that has several accessors. The accessors are:

host

The host ID of this node.

host_url

The URL of the node within the host. (one given in its 'url' key).

label

The label of the node. (one given in its 'value' key). This is not SGML-escaped.

title

The title of the node. (that can be assigned to the URL 'title' attribute). This is not SGML-escaped.

direct_url

A direct URL (usable for inclusion in an A tag ) from the current page to this page.

SEE ALSO

HTML::Widgets::NavMenu::HeaderRole

An HTML::Widgets::NavMenu sub-class that contains support for another role. Used for the navigation menu in http://perl-begin.berlios.de/.

HTML::Widget::SideBar

A module written by Yosef Meller for maintaining a navigation menu. HTML::Widgets::NavMenu originally utilized, but it no longer does. This module does not makes links relative on its own, and tends to generate a lot of JavaScript code by default. It also does not have too many automated test scripts.

HTML::Menu::Hierarchical

A module by Don Owens for generating hierarchical HTML menus. I could not quite understand its tree traversal semantics, so I ended up not using it. Also seems to require that each of the tree node will have a unique ID.

HTML::Widgets::Menu

This module also generates a navigation menu. The CPAN version is relatively old, and the author sent me a newer version. After playing with it a bit, I realized that I could not get it to do what I want (but I cannot recall why), so I abandoned it.

AUTHORS

Shlomi Fish <shlomif@iglu.org.il> (http://search.cpan.org/~shlomif/).

THANKS

Thanks to Yosef Meller (http://search.cpan.org/~yosefm/) for writing the module HTML::Widget::SideBar on which initial versions of this modules were based. (albeit his code is no longer used here).

COPYRIGHT AND LICENSE

Copyright 2004, Shlomi Fish. All rights reserved.

You can use, modify and distribute this module under the terms of the MIT X11 license. ( http://www.opensource.org/licenses/mit-license.php ).