HTML::TokeParser
HTML::TokeParser(3) User Contributed Perl Documentation HTML::TokeParser(3)
NAME
HTML::TokeParser - Alternative HTML::Parser interface
SYNOPSIS
require HTML::TokeParser;
$p = HTML::TokeParser->new("index.html") ||
die "Can't open: $!";
$p->empty_element_tags(1); # configure its behaviour
while (my $token = $p->get_token) {
#...
}
DESCRIPTION
The "HTML::TokeParser" is an alternative interface to the
"HTML::Parser" class. It is an "HTML::PullParser" subclass with a pre-
declared set of token types. If you wish the tokens to be reported
differently you probably want to use the "HTML::PullParser" directly.
The following methods are available:
$p = HTML::TokeParser->new( $filename, %opt );
$p = HTML::TokeParser->new( $filehandle, %opt );
$p = HTML::TokeParser->new( \$document, %opt );
The object constructor argument is either a file name, a file han-
dle object, or the complete document to be parsed. Extra options
can be provided as key/value pairs and are processed as documented
by the base classes.
If the argument is a plain scalar, then it is taken as the name of
a file to be opened and parsed. If the file can't be opened for
reading, then the constructor will return "undef" and $! will tell
you why it failed.
If the argument is a reference to a plain scalar, then this scalar
is taken to be the literal document to parse. The value of this
scalar should not be changed before all tokens have been extracted.
Otherwise the argument is taken to be some object that the
"HTML::TokeParser" can read() from when it needs more data. Typi-
cally it will be a filehandle of some kind. The stream will be
read() until EOF, but not closed.
A newly constructed "HTML::TokeParser" differ from its base classes
by having the "unbroken_text" attribute enabled by default. See
HTML::Parser for a description of this and other attributes that
influence how the document is parsed. It is often a good idea to
enable "empty_element_tags" behaviour.
Note that the parsing result will likely not be valid if raw unde-
coded UTF-8 is used as a source. When parsing UTF-8 encoded files
turn on UTF-8 decoding:
open(my $fh, "<:utf8", "index.html") || die "Can't open 'index.html': $!";
my $p = HTML::TokeParser->new( $fh );
# ...
If a $filename is passed to the constructor the file will be opened
in raw mode and the parsing result will only be valid if its con-
tent is Latin-1 or pure ASCII.
If parsing from an UTF-8 encoded string buffer decode it first:
utf8::decode($document);
my $p = HTML::TokeParser->new( \$document );
# ...
$p->get_token
This method will return the next token found in the HTML document,
or "undef" at the end of the document. The token is returned as an
array reference. The first element of the array will be a string
denoting the type of this token: "S" for start tag, "E" for end
tag, "T" for text, "C" for comment, "D" for declaration, and "PI"
for process instructions. The rest of the token array depend on
the type like this:
["S", $tag, $attr, $attrseq, $text]
["E", $tag, $text]
["T", $text, $is_data]
["C", $text]
["D", $text]
["PI", $token0, $text]
where $attr is a hash reference, $attrseq is an array reference and
the rest are plain scalars. The "Argspec" in HTML::Parser explains
the details.
$p->unget_token( @tokens )
If you find you have read too many tokens you can push them back,
so that they are returned the next time $p->get_token is called.
$p->get_tag
$p->get_tag( @tags )
This method returns the next start or end tag (skipping any other
tokens), or "undef" if there are no more tags in the document. If
one or more arguments are given, then we skip tokens until one of
the specified tag types is found. For example:
$p->get_tag("font", "/font");
will find the next start or end tag for a font-element.
The tag information is returned as an array reference in the same
form as for $p->get_token above, but the type code (first element)
is missing. A start tag will be returned like this:
[$tag, $attr, $attrseq, $text]
The tagname of end tags are prefixed with "/", i.e. end tag is
returned like this:
["/$tag", $text]
$p->get_text
$p->get_text( @endtags )
This method returns all text found at the current position. It will
return a zero length string if the next token is not text. Any
entities will be converted to their corresponding character.
If one or more arguments are given, then we return all text occur-
ring before the first of the specified tags found. For example:
$p->get_text("p", "br");
will return the text up to either a paragraph of linebreak element.
The text might span tags that should be textified. This is con-
trolled by the $p->{textify} attribute, which is a hash that
defines how certain tags can be treated as text. If the name of a
start tag matches a key in this hash then this tag is converted to
text. The hash value is used to specify which tag attribute to
obtain the text from. If this tag attribute is missing, then the
upper case name of the tag enclosed in brackets is returned, e.g.
"[IMG]". The hash value can also be a subroutine reference. In
this case the routine is called with the start tag token content as
its argument and the return value is treated as the text.
The default $p->{textify} value is:
{img => "alt", applet => "alt"}
This means that <IMG> and <APPLET> tags are treated as text, and
that the text to substitute can be found in the ALT attribute.
$p->get_trimmed_text
$p->get_trimmed_text( @endtags )
Same as $p->get_text above, but will collapse any sequences of
white space to a single space character. Leading and trailing
white space is removed.
$p->get_phrase
This will return all text found at the current position ignoring
any phrasal-level tags. Text is extracted until the first non
phrasal-level tag. Textification of tags is the same as for
get_text(). This method will collapse white space in the same way
as get_trimmed_text() does.
The definition of <i>phrasal-level tags</i> is obtained from the
HTML::Tagset module.
EXAMPLES
This example extracts all links from a document. It will print one
line for each link, containing the URL and the textual description
between the <A>...</A> tags:
use HTML::TokeParser;
$p = HTML::TokeParser->new(shift||"index.html");
while (my $token = $p->get_tag("a")) {
my $url = $token->[1]{href} || "-";
my $text = $p->get_trimmed_text("/a");
print "$url\t$text\n";
}
This example extract the <TITLE> from the document:
use HTML::TokeParser;
$p = HTML::TokeParser->new(shift||"index.html");
if ($p->get_tag("title")) {
my $title = $p->get_trimmed_text;
print "Title: $title\n";
}
SEE ALSO
HTML::PullParser, HTML::Parser
COPYRIGHT
Copyright 1998-2005 Gisle Aas.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.8.6 2006-04-26 HTML::TokeParser(3)
