=head1 NAME
XML::TokeParser - Simplified interface to XML::Parser
=head1 SYNOPSIS
use XML::TokeParser;
#
#parse from file
my $p = XML::TokeParser->new('file.xml')
#
#parse from open handle
open IN, 'file.xml' or die $!;
my $p = XML::TokeParser->new( \*IN, Noempty => 1 );
#
#parse literal text
my $text = '<tag xmlns="http://www.omsdev.com">text</tag>';
my $p = XML::TokeParser->new( \$text, Namespaces => 1 );
#
#read next token
my $token = $p->get_token();
#
#skip to <title> and read text
$p->get_tag('title');
$p->get_text();
#
#read text of next <para>, ignoring any internal markup
$p->get_tag('para');
$p->get_trimmed_text('/para');
#
#process <para> if interesting text
$t = $p->get_tag('para');
$p->begin_saving($t);
if ( $p->get_trimmed_text('/para') =~ /interesting stuff/ ) {
$p->restore_saved();
process_para($p);
}
=head1 DESCRIPTION
XML::TokeParser provides a procedural ("pull mode") interface to XML::Parser
in much the same way that Gisle Aas' HTML::TokeParser provides a procedural
interface to HTML::Parser. XML::TokeParser splits its XML input up into
"tokens," each corresponding to an XML::Parser event.
A token is a B<L<bless'd|"XML::TokeParser::Token">> reference to an array whose first element is an event-type
string and whose last element is the literal text of the XML input that
generated the event, with intermediate elements varying according to the
event type.
Each token is an I<object> of type L<XML::TokeParser::Token|"XML::TokeParser::Token">.
Read
L<"XML::TokeParser::Token"|"XML::TokeParser::Token">
to learn what methods are available for inspecting the token,
and retrieving data from it.
=cut
package XML::TokeParser;
use strict;
use vars qw($VERSION);
use Carp;# qw( carp croak );
use XML::Parser;
$VERSION = '0.05';
=head1 METHODS
=over 4
=item $p = XML::TokeParser->new($input, [options])
Creates a new parser, specifying the input source and any options. If
$input is a string, it is the name of the file to parse. If $input is a
reference to a string, that string is the actual text to parse. If $input
is a reference to a typeglob or an IO::Handle object corresponding to an
open file or socket, the text read from the handle will be parsed.
Options are name=>value pairs and can be any of the following:
=over 4
=item Namespaces
If set to a true value, namespace processing is enabled.
=item ParseParamEnt
This option is passed on to the underlying XML::Parser object; see that
module's documentation for details.
=item Noempty
If set to a true value, text tokens consisting of only whitespace (such as
those created by indentation and line breaks in between tags) will be
ignored.
=item Latin
If set to a true value, all text other than the literal text elements of
tokens will be translated into the ISO 8859-1 (Latin-1) character encoding
rather than the normal UTF-8 encoding.
=item Catalog
The value is the URI of a catalog file used to resolve PUBLIC and SYSTEM
identifiers. See XML::Catalog for details.
=back
=cut
sub new {
my $class = shift;
my $source = shift;
my %args = ( Noempty => 0, Latin => 0, Catalog => 0, @_ );
my $self = { output => [], EOF => 0 };
$self->{noempty} = delete $args{Noempty};
$self->{latin} = delete $args{Latin};
my $catname = delete $args{Catalog};
my $parser = XML::Parser->new(%args) or croak "$!";
$parser->setHandlers(
Start => \&start,
End => \&end,
Char => \&char,
Proc => \&proc,
Comment => \&comment
);
if ($catname) {
require XML::Catalog;
my $catalog = XML::Catalog->new($catname) or croak "$!";
$parser->setHandlers( ExternEnt => $catalog->get_handler($parser) );
}
$self->{parser} = $parser->parse_start( TokeParser => $self ) or croak "$!";
if ( ref($source) eq 'SCALAR' ) {
$self->{src} = $source;
$self->{src_offset} = 0;
}
elsif ( ref($source) =~ /^IO:|^GLOB$/ ) {
$self->{srcfile} = $source;
}
else {
require IO::File;
$self->{srcfile} = IO::File->new( $source, 'r' ) or return undef;
$self->{opened} = 1;
}
bless $self, $class;
}
sub DESTROY {
my $self = shift;
$self->{srcfile}->close() if $self->{srcfile} && $self->{opened};
$self->{parser} = undef;
}
=item $token = $p->get_token()
Returns the next token, as an array reference, from the input. Returns
undef if there are no remaining tokens.
=cut
sub get_token {
local $_;
my $self = shift;
$self->parsechunks();
my $token = shift @{ $self->{output} };
while ($self->{noempty}
&& $token
&& $token->[0] eq 'T'
&& $token->[1] =~ /^\s*$/ )
{
$self->parsechunks();
$token = shift @{ $self->{output} };
}
if ( defined $token and exists $self->{savebuff} ) {
push @{ $self->{savebuff} }, [@$token];
}
return() unless defined $token;
bless $token, 'XML::TokeParser::Token';
}
=item $p->unget_token($token,...)
Pushes tokens back so they will be re-read. Useful if you've read one or
more tokens too far. Correctly handles "partial" tokens returned by
get_tag().
=cut
sub unget_token {
my $self = shift;
while ( my $token = pop @_ ) {
if ( @$token == 4 && ref( $token->[1] ) eq 'HASH' ) {
$token = [ 'S', @$token ];
}
elsif ( @$token == 2 && substr( $token->[0], 0, 1 ) eq '/' ) {
$token = [ 'E', substr( $token->[0], 1 ), $token->[1] ];
}
unshift @{ $self->{output} }, $token;
}
}
=item $token = $p->get_tag( [$token] )
If no argument given, skips tokens until the next start tag or end tag
token. If an argument is given, skips tokens until the start tag or end tag
(if the argument begins with '/') for the named element. The returned
token does not include an event type code; its first element is the element
name, prefixed by a '/' if the token is for an end tag.
=cut
sub get_tag {
my ( $self, $tag ) = @_;
my $token;
while ( $token = $self->get_token() ) {
my $type = shift @$token;
next unless $type =~ /[SE]/;
substr( $token->[0], 0, 0 ) = '/' if $type eq 'E';
last unless ( defined($tag) && $token->[0] ne $tag );
}
$token;
}
=item $text = $p->get_text( [$token] )
If no argument given, returns the text at the current position, or an empty
string if the next token is not a 'T' token. If an argument is given,
gathers up all text between the current position and the specified start or
end tag, stripping out any intervening tags (much like the way a typical
Web browser deals with unknown tags).
=cut
sub get_text {
my ( $self, $tag ) = @_;
my $text = "";
my $token;
while ( $token = $self->get_token() ) {
my $type = $token->[0];
if ( $type eq 'T' ) {
$text .= $token->[1];
}
elsif ( $type =~ /[SE]/ ) {
my $tt = $token->[1];
$tt = "/$tt" if $type eq 'E';
last if ( !defined($tag) || $tt eq $tag );
}
elsif ( $type eq 'PI' ) {
last;
}
}
if ($token) {
$self->unget_token($token);
pop @{ $self->{savebuff} } if exists $self->{savebuff};
}
$text;
}
=item $text = $p->get_trimmed_text( [$token] )
Like get_text(), but deletes any leading or trailing whitespaces and
collapses multiple whitespace (including newlines) into single spaces.
=cut
sub get_trimmed_text {
my $self = shift;
my $text = $self->get_text(@_);
$text =~ s/^\s+//;
$text =~ s/\s+$//;
$text =~ s/\s+/ /g;
$text;
}
=item $p->begin_saving( [$token] )
Causes subsequent calls to get_token(), get_tag(), get_text(), and
get_trimmed_text() to save the returned tokens. In conjunction with
restore_saved(), allows you to "back up" within a token stream. If an
argument is supplied, it is placed at the beginning of the list of saved
tokens (useful because you often won't know you want to begin saving until
you've already read the first token you want saved).
=cut
sub begin_saving {
my $self = shift;
delete $self->{savebuff} if exists $self->{savebuff};
$self->{savebuff} = [];
push @{ $self->{savebuff} }, @_ if @_;
}
=item $p->restore_saved()
Pushes all the tokens saved by begin_saving() back onto the token stream.
Stops saving tokens. To cancel saving without backing up, call
begin_saving() and restore_saved() in succession.
=back
=cut
sub restore_saved {
my $self = shift;
if ( exists $self->{savebuff} ) {
$self->unget_token( @{ $self->{savebuff} } );
delete $self->{savebuff};
}
}
=for comment
=cut
sub parsechunks {
my ($self) = @_;
my $buf = '';
while ( ( !@{ $self->{output} } || $self->{output}[-1][0] eq 'T' )
&& !$self->{EOF} )
{
# if (defined($self->{src}) && ($self->{src_offset}<length(${$self->{src}}))) {
# $buf=substr(${$self->{src}},$self->{src_offset},4096);
# $self->{src_offset}+=4096;
# }
if ( defined( $self->{src} ) ) {
if ( $self->{src_offset} < length( ${ $self->{src} } ) ) {
$buf = substr( ${ $self->{src} }, $self->{src_offset}, 4096 );
$self->{src_offset} += 4096;
}
}
else {
read( $self->{srcfile}, $buf, 4096 );
}
if ( length($buf) == 0 ) {
$self->{EOF} = 1;
$self->{parser}->parse_done();
}
else {
$self->{parser}->parse_more($buf);
}
}
}
=for comment Start handler
=cut
sub start {
my ( $parser, $element, @attrs ) = @_;
my $self = $parser->{TokeParser};
push @{ $self->{output} },
[ 'S', $self->nsname($element), {}, [], $parser->original_string() ];
while (@attrs) {
my ( $name, $val ) = ( shift @attrs, shift @attrs );
$name = $self->nsname($name);
$val = $self->encode($val);
$self->{output}[-1][2]{$name} = $val;
push @{ $self->{output}[-1][3] }, $name;
}
}
=for comment End handler
=cut
sub end {
my ( $parser, $element ) = @_;
my $self = $parser->{TokeParser};
push @{ $self->{output} },
[ 'E', $self->nsname($element), $parser->original_string() ];
}
=for comment Char handler
=cut
sub char {
my ( $parser, $text ) = @_;
my $self = $parser->{TokeParser};
$text = $self->encode($text);
if ( @{ $self->{output} } && $self->{output}[-1][0] eq 'T' ) {
$self->{output}[-1][1] .= $text;
$self->{output}[-1][-1] .= $parser->original_string();
}
else {
push @{ $self->{output} }, [ 'T', $text, $parser->original_string() ];
}
}
=for comment
=cut
sub proc {
my ( $parser, $target, $value ) = @_;
my $self = $parser->{TokeParser};
push @{ $self->{output} },
[
"PI", $self->encode($target),
$self->encode($value), $parser->original_string()
];
}
=for comment Comment handler
=cut
sub comment {
my ( $parser, $text ) = @_;
my $self = $parser->{TokeParser};
push @{ $self->{output} },
[ "C", $self->encode($text), $parser->original_string() ];
}
=for comment nsname
figures out the Namespace if Namespaces is on
=cut
sub nsname {
my ( $self, $name ) = @_;
my $parser = $self->{parser};
if ( $parser->{Namespaces} ) {
my $ns = $parser->namespace($name) || '';
$name = "{$ns}" . $name;
}
return $self->encode($name);
}
=for comment
=cut
sub encode {
my ( $self, $text ) = @_;
if ( $self->{latin} ) {
$text =~ s{([\xc0-\xc3])(.)}{
my $hi = ord($1);
my $lo = ord($2);
chr((($hi & 0x03) <<6) | ($lo & 0x3F))
}ge;
}
$text;
}
package XML::TokeParser::Token;
use strict;
=head2 XML::TokeParser::Token
A token is a blessed array reference,
that you acquire using C<$p-E<gt>get_token> or C<$p-E<gt>get_tag>,
and that might look like:
["S", $tag, $attr, $attrseq, $raw]
["E", $tag, $raw]
["T", $text, $raw]
["C", $text, $raw]
["PI", $target, $data, $raw]
If you don't like remembering array indices (you're a real programmer),
you may access the attributes of a token like:
C<$t-E<gt>tag>, C<$t-E<gt>attr>, C<$t-E<gt>attrseq>, C<$t-E<gt>raw>,
C<$t-E<gt>text>, C<$t-E<gt>target>, C<$t-E<gt>data>.
B<****Please note that this may change in the future,>
B<where as there will be 4 token types, XML::TokeParser::Token::StartTag ....>
What kind of token is it?
To find out, inspect your token using any of these is_* methods
(1 == true, 0 == false, d'oh):
=over 4
=item is_text
=item is_comment
=item is_pi which is short for is_process_instruction
=item is_start_tag
=item is_end_tag
=item is_tag
=back
=cut
# test your token, but don't toke
#sub toke { croak "Don't toke!!!!"; }
sub is_text { return 1 if $_[0]->[0] eq 'T'; return 0;}
sub is_comment { return 1 if $_[0]->[0] eq 'C'; return 0;}
sub is_pi { return 1 if $_[0]->[0] eq 'PI'; return 0;}
#sub is_process_instruction { goto &is_pi; }
{
no strict;
*is_process_instruction = *is_pi;
}
sub is_start_tag {
if( $_[0]->[0] eq 'S'
or ( @{$_[0]} == 4 && ref( $_[0]->[1] ) eq 'HASH' )
){
if(defined $_[1]){
return 1 if $_[0]->[1] eq $_[1];
} else {
return 1;
}
}
return 0;
}
sub is_end_tag {
if( $_[0]->[0] eq 'E'
or ( @{$_[0]} == 2 && substr( $_[0]->[0], 0, 1 ) eq '/' )
){
if(defined $_[1]){
return 1 if $_[0]->[1] eq $_[1];
} else {
return 1;
}
}
return 0;
}
sub is_tag {
if( $_[0]->[0] eq 'S'
or $_[0]->[0] eq 'E'
or ( @{$_[0]} == 4 && ref( $_[0]->[1] ) eq 'HASH' )
or ( @{$_[0]} == 2 && substr( $_[0]->[0], 0, 1 ) eq '/' )
){
if( defined $_[1] ){
return 1 if $_[0]->[1] eq $_[1];
} else {
return 1;
}
}
return 0;
}
=pod
What's that token made of?
To retrieve data from your token, use any of the following methods,
depending on the kind of token you have:
=over 4
=item target
only for process instructions
=cut
sub target { return $_[0]->[1] if $_[0]->is_pi; }
=item data
only for process instructions
=cut
sub data { return $_[0]->[2] if $_[0]->is_pi; }
=item raw
for all tokens
=cut
sub raw { return $_[0]->[-1]; }
=item attr
only for start tags, returns a hashref ( C<print "#link ", >C<$t-E<gt>attr>C<-E<gt>{href}> ).
=cut
#sub attr { return $_[0]->[2] if $_[0]->is_start_tag(); }
sub attr { return $_[0]->[-3] if $_[0]->is_start_tag(); }
=item my $attrseq = $t->attrseq
only for start tags, returns an array ref of the keys found in C<$t-E<gt>attr>
in the order they originally appeared in.
=cut
#sub attrseq { return $_[0]->[3] if $_[0]->is_start_tag(); }
sub attrseq { return $_[0]->[-2] if $_[0]->is_start_tag(); }
#for S|E
=item my $tagname = $t->tag
only for tags ( C<print "opening ", >C<$t-E<gt>tag>C< if >C<$t-E<gt>is_start_tag> ).
=cut
sub tag { return $_[0]->[1] if $_[0]->is_tag; }
=item my $text = $token->text
only for tokens of type text and comment
=back
=cut
sub text { return $_[0]->[1] if $_[0]->is_text or $_[0]->is_comment; }
1;
=pod
Here's more detailed info about the tokens.
=over 4
=item Start tag
The token has five elements: 'S', the element's name, a reference to a hash
of attribute values keyed by attribute names, a reference to an array of
attribute names in the order in which they appeared in the tag, and the
literal text.
=item End tag
The token has three elements: 'E', the element's name, and the literal text.
=item Character data (text)
The token has three elements: 'T', the parsed text, and the literal text.
All contiguous runs of text are gathered into single tokens; there will
never be two 'T' tokens in a row.
=item Comment
The token has three elements: 'C', the parsed text of the comment, and the
literal text.
=item Processing instruction
The token has four elements: 'PI', the target, the data, and the literal
text.
=back
The literal text includes any markup delimiters (pointy brackets,
<![CDATA[, etc.), entity references, and numeric character references and
is in the XML document's original character encoding. All other text is in
UTF-8 (unless the Latin option is set, in which case it's in ISO-8859-1)
regardless of the original encoding, and all entity and character
references are expanded.
If the Namespaces option is set, element and attribute names are prefixed
by their (possibly empty) namespace URIs enclosed in curly brackets and
xmlns:* attributes do not appear in 'S' tokens.
=head1 DIFFERENCES FROM HTML::TokeParser
Uses a true XML parser rather than a modified HTML parser.
Text and comment tokens include extracted text as well as literal text.
PI tokens include target and data as well as literal text.
No tokens for declarations.
No "textify" hash.
unget_token correctly handles partial tokens returned by get_tag().
begin_saving() and restore_saved()
=head1 EXAMPLES
Example:
use XML::TokeParser;
use strict;
#
my $text = '<tag foo="bar" foy="floy"> some text <!--comment--></tag>';
my $p = XML::TokeParser->new( \$text );
#
print $/;
#
while( defined( my $t = $p->get_token() ) ){
local $\="\n";
print ' raw = ', $t->raw;
#
if( $t->tag ){
print ' tag = ', $t->tag;
#
if( $t->is_start_tag ) {
print ' attr = ', join ',', %{$t->attr};
print ' attrseq = ', join ',', @{$t->attrseq};
}
#
print 'is_tag ', $t->is_tag;
print 'is_start_tag ', $t->is_start_tag;
print 'is_end_tag ', $t->is_end_tag;
}
elsif( $t->is_pi ){
print ' target = ', $t->target;
print ' data = ', $t->data;
print 'is_pi ', $t->is_pi;
}
else {
print ' text = ', $t->text;
print 'is_text ', $t->is_text;
print 'is_comment ', $t->is_comment;
}
#
print $/;
}
__END__
Output:
raw = <tag foo="bar" foy="floy">
tag = tag
attr = foo,bar,foy,floy
attrseq = foo,foy
is_tag 1
is_start_tag 1
is_end_tag 0
raw = some text
text = some text
is_text 1
is_comment 0
raw = <!--comment-->
text = comment
is_text 0
is_comment 1
raw = </tag>
tag = tag
is_tag 1
is_start_tag 0
is_end_tag 1
=head1 BUGS
To report bugs, go to
E<lt>http://rt.cpan.org/NoAuth/Bugs.html?Dist=XML-TokeParserE<gt>
or send mail to E<lt>bug-XML-Tokeparser@rt.cpan.orgE<gt>
=head1 AUTHOR
Copyright (c) 2003 D.H. aka PodMaster (current maintainer).
Copyright (c) 2001 Eric Bohlman (original author).
All rights reserved.
This program is free software;
you can redistribute it and/or modify it
under the same terms as Perl itself.
If you don't know what this means,
visit E<lt>http://perl.com/E<gt> or E<lt>http://cpan.org/E<gt>.
=head1 SEE ALSO
L<HTML::TokeParser>,
L<XML::Parser>,
L<XML::Catalog>,
L<XML::Smart>,
L<XML::Twig>.
=cut