Provided by: libhtml-widgets-navmenu-perl_1.0702-1_all 
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",
'text' => "Top 1",
'title' => "T1 Title",
'expand_re' => "",
'subs' =>
[
{
'text' => "Home",
'url' => "",
},
{
'text' => "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.) You can start
from the example above and see more examples in the tests, and complete working sites in the Subversion
repositories at <http://opensvn.csie.org/shlomif/homepage/> and
<http://opensvn.csie.org/perlbegin/perl-begin/>.
USAGE
my $nav_menu = HTML::Widgets::NavMenu->new(@args)
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 required 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.
An optional key that is required only if you wish to use the "site_abs" url_type (see below), is
"trailing_url_base", which denotes the component of the site that appears after the hostname. For
"http://www.myhost.com/~myuser/" it is "/~myuser/".
Here's an example for a minimal hosts value:
'hosts' =>
{
'default' =>
{
'base_url' => "http://www.hello.com/",
'trailing_url_base' => "/",
},
},
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/",
'trailing_url_base' => "/",
},
'vipe' =>
{
'base_url' => "http://vipe.technion.ac.il/~shlomif/",
'trailing_url_base' => "/~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.
no_leading_dot
When this parameter is set to 1, the object will try to generate URLs that do not start with "./"
when possible. That way, the generated markup will be a little more compact. This option is not
enabled by default for backwards compatibility, but is highly recommended.
A complete invocation of an HTML::Widgets::NavMenu constructor can be found in the SYNOPSIS above.
After you _init 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 node description 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 Node Description Component Class".
'nav_links_obj'
This points to a hash reference whose keys are link IDs for the Firefox "Site Navigation Toolbar" (
<http://www.bolwin.com/software/snb.shtml> ) and compatible programs, and its values are Node
Description objects. (see "The Node Description Class" below). Here's a sample code that renders the
links as "<link rel=...>" into the page header:
my $nav_links = $results->{'nav_links_obj'};
# Sort the keys so their order will be preserved
my @keys = (sort { $a cmp $b } keys(%$nav_links));
foreach my $key (@keys)
{
my $value = $nav_links->{$key};
my $url = CGI::escapeHTML($value->direct_url());
my $title = CGI::escapeHTML($value->title());
print {$fh} "<link rel=\"$key\" href=\"$url\" title=\"$title\" />\n";
}
'nav_links'
This points to a hash reference whose keys are link IDs compatible with the Firefox Site Navigation (
<http://cdn.mozdev.org/linkToolbar/> ) and its values are the URLs to these links. This key/value
pair is provided for backwards compatibility with older versions of HTML::Widgets::NavMenu. In new
code, one is recommended to use 'nav_links_obj' instead.
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";
}
$results = $nav_menu->render_jquery_treeview()
Renders a fully expanded tree suitable for input to JQuery's treeview plugin:
<http://bassistance.de/jquery-plugins/jquery-plugin-treeview/> - otherwise the same as render() .
$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 reference
to an array containing the tags of the site map.
$url = $nav_menu->get_cross_host_rel_url_ref({...})
This function can be called to calculate a URL to a different part of the site. It accepts four named
arguments, passed as a hash-ref:
'host' This is the host ID
'host_url'
This is URL within the host.
'url_type'
'rel', 'full_abs' or 'site_abs'.
'url_is_abs'
A flag that indicates if 'host_url' is already absolute.
$url = $nav_menu->get_cross_host_rel_url(...)
This is like get_cross_host_rel_url_ref() except that the arguments are clobbered into the arguments
list. It is kept here for compatibility sake.
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.
'text'
This is the text that will be presented to the user as the text of the link inside the navigation
bar. E.g.: if 'text' 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'
This specifies a predicate (a Perl value that is evaluated to a boolean value, see "Predicate Values"
below.) to be matched against the path and current host 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.
'url_type'
This specifies the URL type to use to render this item. It can be:
1. "rel" - the default. This means a fully relative URL (if possible), like "../../me/about.html".
2. "site_abs" - this uses a URL absolute to the site, using a slash at the beginning. Like
"/~shlomif/me/about.html". For this to work the current host needs to have a 'trailing_url_base'
value set.
3. "full_abs" - this uses a fully qualified URL (e.g: with "http://" at the beginning, even if both
the current path and the pointed path belong to the same host. Something like
"http://www.shlomifish.org/me/about.html".
'rec_url_type'
This is similar to 'url_type' only it recurses, to the sub-tree of the node. If both 'url_type' and
'rec_url_type' are specified for a node, then the value of 'url_type' will hold.
'url_is_abs'
This flag, if true, indicates that the URL specified by the 'url' key is an absolute URL like
"http://www.myhost.com/" and should not be treated as a path within the site. All links to the page
associated with this node will contain the URL verbatim.
Note that using absolute URLs as part of the site flow is discouraged because once they are accessed,
the navigation within the primary site is lost. A better idea would be to create a separate page
within the site, that will link to the external URL.
li_id
This is the HTML ID attribute that will be assigned to the specific "<li>" tag of the navigation
menu. So if you have:
'tree_contents' =>
{
'host' => "default",
'text' => "Top 1",
'title' => "T1 Title",
'expand_re' => "",
'subs' =>
[
{
'text' => "Home",
'url' => "",
},
{
'text' => "About Me",
'title' => "About Myself",
'url' => "me/",
'li_id' => 'about_me',
},
],
},
Then the HTML for the About me will look something like:
<li id="about_me">
<a href="me/ title="About Myself">About Me</a>
</li>
Predicate Values
An explicitly specified predicate value is a hash reference that contains one of the following three keys
with their appropriate values:
'cb' => \&predicate_func
This specifies a sub-routine reference (or "callback" or "cb"), that will be called to determine the
result of the predicate. It accepts two named arguments - 'path_info' which is the path of the
current page (without the leading slash) and 'current_host' which is the ID of the current host.
Here is an example for such a callback:
sub predicate_cb1
{
my %args = (@_);
my $host = $args{'current_host'};
my $path = $args{'path_info'};
return (($host eq "true") && ($path eq "mypath/"));
}
're' => $regexp_string
This specifies a regular expression to be matched against the path_info (regardless of what
current_host is), to determine the result of the predicate.
'bool' => [ 0 | 1 ]
This specifies the constant boolean value of the predicate.
Note that if 'cb' is specified then both 're' and 'bool' will be ignored, and 're' over-rides 'bool'.
Orthogonal to these keys is the 'capt' key which specifies whether this expansion "captures" or not. This
is relevant to the behaviour in the breadcrumbs' trails, if one wants the item to appear there or not.
The default value is true.
If the predicate is not a hash reference, then HTML::Widgets::NavMenu will try to guess what it is. If
it's a sub-routine reference, it will be an implicit callback. If it's one of the values "0", "1", "yes",
"no", "true", "false", "True", "False" it will be considered a boolean. If it's a different string, a
regular expression match will be attempted. Else, an excpetion will be thrown.
Here are some examples for predicates:
# Always expand.
'expand' => { 'bool' => 1, };
# Never expand.
'expand' => { 'bool' => 0, };
# Expand under home/
'expand' => { 're' => "^home/" },
# Expand under home/ when the current host is "foo"
sub expand_path_home_host_foo
{
my %args = (@_);
my $host = $args{'current_host'};
my $path = $args{'path_info'};
return (($host eq "foo") && ($path =~ m!^home/!));
}
'expand' => { 'cb' => \&expand_path_home_host_foo, },
The Node Description Class
When retrieving the leading path or the "nav_links_obj", 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 'text' 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.
url_type
This is the "url_type" (see above) that holds for this node.
SEE ALSO
See the article Shlomi Fish wrote for Perl.com for a gentle introduction to HTML-Widgets-NavMenu:
<http://www.perl.com/pub/a/2005/07/07/navwidgets.html>
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.org/>.
HTML::Widget::SideBar
A module written by Yosef Meller for maintaining a navigation menu. HTML::Widgets::NavMenu
originally utilized it, but 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@cpan.org>, <http://www.shlomifish.org/> .
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> ).