HTML::TokeParser - Alternative HTML::Parser interface
require HTML::TokeParser;
$p = HTML::TokeParser->new("index.html") ||
die "Can't open: $!";
while (my $token = $p->get_token) {
#...
}
The HTML::TokeParser is an alternative interface to the
HTML::Parser class. It is an HTML::PullParser subclass with a
predeclared 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:
The object constructor argument is either a file name, a file handle object, or the complete document to be parsed.
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. Typically
it will be a filehandle of some kind. The stream will be read() until
EOF, but not closed.
Note that the parsing result will likely not be valid if raw undecoded 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 $filename is passed to the constructor the file will be opened in raw mode and the parsing result will only be valid if its content is Latin-1 or pure ASCII.
If parsing from an UTF-8 encoded string buffer decode it first:
utf8::decode($document); my $p = HTML::TokeParser->new( \$document ); # ...
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 HTML::Parser/Argspec explains the details.
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]
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 occurring 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 controlled 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.
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.
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";
}
HTML::PullParser, HTML::Parser
Copyright 1998-2001 Gisle Aas.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.