NAME
Parse::BBCode - Module to turn BBCode into HTML or plain text
SYNOPSIS
To parse a bbcode string, set up a parser with the default HTML defintions of Parse::BBCode::HTML:
use Parse::BBCode;
my $p = Parse::BBCode->new();
my $code = 'some [b]b code[/b]';
my $parsed = $p->render($code);
Or if you want to define your own tags:
my $p = Parse::BBCode->new({
tags => {
# load the default tags
Parse::BBCode::HTML->defaults,
# add/override tags
url => 'url:<a href="%{link}A">%{parse}s</a>',
i => '<i>%{parse}s</i>',
b => '<b>%{parse}s</b>',
noparse => '<pre>%{html}s</pre>',
code => sub {
my ($parser, $attr, $content, $attribute_fallback) = @;
if ($attr eq 'perl') {
# use some syntax highlighter
$content = highlightperl($content);
}
else {
$content = Parse::BBCode::escape_html($$content);
}
"<tt>$content</tt>"
},
test => 'this is klingon: %{klingon}s',
},
escapes => {
klingon => sub {
my ($parser, $tag, $text) = @;
return translateinto_klingon($text);
},
},
}
);
my $code = 'some [b]b code[/b]';
my $parsed = $p->render($code);
DESCRIPTION
Note: This module is still experimental, the syntax is subject to change. I'm open for any suggestions on how to improve the syntax. See "TODO" for what might change.
I wrote this module because HTML::BBCode is not extendable (or I didn't see how) and BBCode::Parser seemed good at the first glance but has some issues, for example it says that he following bbode
[code] foo [b] [/code]
is invalid, while I think you should be able to write unbalanced code in code tags. Also BBCode::Parser dies if you have invalid code or not-permitted tags, but in a forum you'd rather show a partly parsed text then an error message.
What I also wanted is an easy syntax to define own tags, ideally - for simple tags - as plain text, so you can put it in a configuration file. This allows forum admins to add tags easily. Some forums might want a tag for linking to perlmonks.org, other forums need other tags.
Another goal was to always output a result and don't die. I might add an option which lets the parser die with unbalanced code.
METHODS
new Constructor. Takes a hash reference with options as an argument.
my $parser = Parse::BBCode->new({
tags => {
url => ...,
i => ...,
},
escapes => {
link => ...,
},
close_open_tags => 1, # default 0
strict_attributes => 0, # default 0
);
tags
See "TAG DEFINITIONS"
escapes
See "ESCAPES"
close_open_tags
If set to true (1), it will close open tags at the end or before
block tags.
strict_attributes
If set to true (1), tags with invalid attributes are left
unparsed. If set to false (0), the attribute for this tags will
be empty.
An invalid attribute:
[foo=bar far boo]...[/foo]
I might add an option to define your own attribute validation.
Contact me if you'd like to have this.
direct_attributes
Default: true
Normal tag syntax is:
[tag=val1 attr2=val2 ...]
If set to 0, tag syntax is
[tag attr2=val2 ...]
render
Input: The text to parse
Returns: the rendered text
my $parsed = $parser->render($bbcode);
parse
Input: The text to parse.
Returns: the parsed tree (a Parse::BBCode::Tag object)
my $tree = $parser->parse($bbcode);
render_tree
Input: the parse tree
Returns: The rendered text
my $parsed = $parser->render_tree($tree);
forbid
$parser->forbid(qw/ img url /);
Disables the given tags.
permit
$parser->permit(qw/ img url /);
Enables the given tags if they are in the tag definitions.
escape_html
Utility to substitute
<>&"'
with their HTML entities.
my $escaped = Parse::BBCode::escape_html($text);
error
If the given bbcode is invalid (unbalanced or wrongly nested
classes), currently Parse::BBCode::render() will either leave the
invalid tags unparsed, or, if you set the option "close_open_tags",
try to add closing tags. If this happened "error()" will return the
invalid tag(s), otherwise false. To get the corrected bbcode (if you
set "close_open_tags") you can get the tree and return the raw text
from it:
if ($parser->error) {
my $tree = $parser->get_tree;
my $corrected = $tree->raw_text;
}
TAG DEFINITIONS
Here is an example of all the current definition possibilities:
my $p = Parse::BBCode->new({
tags => {
'' => sub {
my ($parser, $attr, $content, $info) = @;
# for explanation of $info see below
# at "Define subroutine for tag"
my $e = Parse::BBCode::escapehtml($content);
$e =~ s/\r?\n|\r/<br>\n/g;
$e
},
i => '<i>%s</i>',
b => '<b>%{parse}s</b>',
size => '<font size="%a">%{parse}s</font>',
url => 'url:<a href="%{link}A">%{parse}s</a>',
wikipedia => 'url:<a href="http://wikipedia.../?search=%{uri}A">%{parse}s</a>',
noparse => '<pre>%{html}s</pre>',
quote => 'block:<blockquote>%s</blockquote>',
code => {
code => sub {
my ($parser, $attr, $content, $attribute_fallback) = @;
if ($attr eq 'perl') {
# use some syntax highlighter
$content = highlightperl($$content);
}
else {
$content = Parse::BBCode::escape_html($$content);
}
"<tt>$content</tt>"
},
parse => 0,
class => 'block',
},
hr => {
class => 'block',
output => '<hr>',
single => 1,
},
},
}
);
The following list explains the above tag definitions:
Plain text not in tags
This defines how plain text should be rendered:
'' => sub {
my $e = Parse::BBCode::escape_html($_[2]);
$e =~ s/\r?\n|\r/<br>\n/g;
$e
},
In the most cases, you would want HTML escaping like shown above.
This is the default, so you can leave it out. Only if you want to
render BBCode into plain text or something else, you need this
option.
%s
i => '<i>%s</i>'
[i] italic <html> [/i]
turns out as
<i> italic <html> </i>
So %s stands for the tag content. By default, it is parsed itself,
so that you can nest tags.
"%{parse}s"
b => '<b>%{parse}s</b>'
[b] bold <html> [/b]
turns out as
<b> bold <html> </b>
"%{parse}s" is the same as %s because 'parse' is the default.
%a
size => '<font size="%a">%{parse}s</font>'
[size=7] some big text [/size]
turns out as
<font size="7"> some big text </font>
So %a stands for the tag attribute. By default it will be HTML
escaped.
url tag, %A, "%{link}A"
url => 'url:<a href="%{link}a">%{parse}s</a>'
the first thing you can see is the "url:" at the beginning - this
defines the url tag as a tag with the class 'url', and urls must not
be nested. So this class definition is mainly there to prevent
generating wrong HTML. if you nest url tags only the outer one will
be parsed.
another thing you can see is how to apply a special escape. The
attribute defined with "%{link}a" is checked for a valid URL.
"javascript:" will be filtered.
[url=/foo.html]a link[/url]
turns out as
<a href="/foo.html">a link</a>
Note that a tag like
[url]http://some.link.example[/url]
will turn out as
<a href="">http://some.link.example</a>;
In the cases where the attribute should be the same as the content
you should use %A instead of %a which takes the content as the
attribute as a fallback. You probably need this in all url-like
tags:
url => 'url:<a href="%{link}A">%{parse}s</a>',
"%{uri}A"
You might want to define your own urls, e.g. for wikipedia
references:
wikipedia => 'url:<a href="http://wikipedia/?search=%{uri}A">%{parse}s</a>',
"%{uri}A" will uri-encode the searched term:
[wikipedia]Harold & Maude[/wikipedia]
[wikipedia="Harold & Maude"]a movie[/wikipedia]
turns out as
<a href="http://wikipedia/?search=Harold+%26+Maude">Harold & Maude</a>
<a href="http://wikipedia/?search=Harold+%26+Maude">a movie</a>
Don't parse tag content
Sometimes you need to display verbatim bbcode. The simplest form
would be a noparse tag:
noparse => '<pre>%{html}s</pre>'
[noparse] [some]unbalanced[/foo] [/noparse]
With this definition the output would be
<pre> [some]unbalanced[/foo] </pre>
So inside a noparse tag you can write (almost) any invalid bbcode.
The only exception is the noparse tag itself:
[noparse] [some]unbalanced[/foo] [/noparse] [b]really bold[/b] [/noparse]
Output:
[some]unbalanced[/foo] <b>really bold</b> [/noparse]
Because the noparse tag ends at the first closing tag, even if you
have an additional opening noparse tag inside.
The "%{html}s" defines that the content should be HTML escaped. If
you don't want any escaping you can't say %s because the default is
'parse'. In this case you have to write "%{noescape}".
Block tags
quote => 'block:<blockquote>%s</blockquote>',
To force valid html you can add classes to tags. The default class
is 'inline'. To declare it as a block add "'block:"" to the start of
the string. Block tags inside of inline tags will either close the
outer tag(s) or leave the outer tag(s) unparsed, depending on the
option "close_open_tags".
Define subroutine for tag
All these definitions might not be enough if you want to define your
own code, for example to add a syntax highlighter.
Here's an example:
code => {
code => sub {
my ($parser, $attr, $content, $attribute_fallback, $tag, $info) = @;
if ($attr eq 'perl') {
# use some syntax highlighter
$content = highlightperl($$content);
}
else {
$content = Parse::BBCode::escape_html($$content);
}
"<tt>$content</tt>"
},
parse => 0,
class => 'block',
},
So instead of a string you define a hash reference with a 'code' key
and a sub reference. The other key is "parse" which is 0 by default.
If it is 0 the content in the tag won't be parsed, just as in the
noparse tag above. If it is set to 1 you will get the rendered
content as an argument to the subroutine.
The first argument to the subroutine is the Parse::BBCode object
itself. The second argument is the attribute, the third is the
already rendered tag content as a scalar reference and the fourth
argument is the attribute fallback which is set to the content if
the attribute is empty. The fourth argument is just for convenience.
The fifth argument is the tag object (Parse::BBCode::Tag) itself, so
if necessary you can get the original tag content by using:
my $original = $tag->raw_text;
The sixth argument is an info hash. It contains:
my $info = {
tags => $tags,
stack => $stack,
classes => $classes,
};
The variable $tags is a hashref which contains all tag names which
are outside the current tag, with a count. This is convenient if you
have to check if the current processed tag is inside a certain tag
and you want to behave differently, like
if ($info->{tags}->{special}) {
# we are somewhere inside [special]...[/special]
}
The variable $stack contains an array ref with all outer tag names.
So while processing the tag 'i' in
[quote][quote][b]bold [i]italic[/i][/b][/quote][/quote]
it contains [qw/ quote quote b i /]
The variable $classes contains a hashref with all tag classes and
their counts outside of the current processed tag. For example if
you want to process URIs with URI::Find, and you are already in a
tag with the class 'url' then you don't want to use URI::Find here.
unless ($info->{classes}->{url}) {
# not inside of a url class tag ([url], [wikipedia, etc.)
# parse text for urls with URI::Find
}
Single-Tags
Sometimes you might want single tags like for a horizontal line:
hr => {
class => 'block',
output => '<hr>',
single => 1,
},
The hr-Tag is a block tag (should not be inside inline tags), and it
has no closing tag (option "single")
[hr]
Output:
<hr>
ESCAPES
my $p = Parse::BBCode->new({
...
escapes => {
link => sub {
},
},
});
You can define or override escapes. Default escapes are html, uri, link, email, htmlcolor, num. An escape functions as a validator and filter. For example, the 'link' escape looks if it got a valid URI (starting with "/" or "\w+://") and html-escapes it. It returns the empty string if the input is invalid.
See "default_escapes" in Parse::BBCode::HTML for the detailed list of escapes.
TODO
BBCode to Textile|Markdown
There is a Parse::BBCode::Markdown module which is only roughly
tested.
API The main syntax is likely to stay, only the API for callbacks might
change. At the moment it is not possible to add callbacks to the
parsing process, only for the rendering phase. It is also not
possible to declare your own attribute syntax, for example
[quote=nickname date]
Attributes always have to look like:
[tag=main_attribute other=foo]...
[tag="main_attribute" other="foo"]...
Redirects for url tags
In a forum you might want to prefix links and images with a redirect
script so that the actual referrer will be hidden from the target
url. This is extremely helpful if you are using session-ids in your
urls. I plan to add an option for url tags which lets you define the
redirect-script url.
REQUIREMENTS
perl >= 5.6.1, Class::Accessor::Fast, URI::Escape
SEE ALSO
BBCode::Parser, HTML::BBCode, HTML::BBReverse
See "examples/compare.html" for a feature comparison of the modules and feel free to report mistakes.
See "examples/bench.pl" for a benchmark of the modules.
BUGS
Please report bugs at
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Parse-BBCode
AUTHOR
Tina Mueller
CREDITS
Thanks to Moritz Lenz for his suggestions about the implementation and the test cases.
Viacheslav Tikhanovskii
Sascha Kiefer
COPYRIGHT AND LICENSE
Copyright (C) 2008 by Tina Mueller
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.6.1 or, at your option, any later version of Perl 5 you may have available.