ÿØÿà JFIF ÿÛ „ ( %!1!%*+... 983,7(-.-
Reader.pod 0000444 00000043147 15234477232 0006472 0 ustar 00 =head1 NAME
XML::LibXML::Reader - XML::LibXML::Reader - interface to libxml2 pull parser
=head1 SYNOPSIS
use XML::LibXML::Reader;
my $reader = XML::LibXML::Reader->new(location => "file.xml")
or die "cannot read file.xml\n";
while ($reader->read) {
processNode($reader);
}
sub processNode {
my $reader = shift;
printf "%d %d %s %d\n", ($reader->depth,
$reader->nodeType,
$reader->name,
$reader->isEmptyElement);
}
or
my $reader = XML::LibXML::Reader->new(location => "file.xml")
or die "cannot read file.xml\n";
$reader->preservePattern('//table/tr');
$reader->finish;
print $reader->document->toString(1);
=head1 DESCRIPTION
This is a perl interface to libxml2's pull-parser implementation xmlTextReader I<<<<<< http://xmlsoft.org/html/libxml-xmlreader.html >>>>>>. This feature requires at least libxml2-2.6.21. Pull-parsers (such as StAX in
Java, or XmlReader in C#) use an iterator approach to parse XML documents. They
are easier to program than event-based parser (SAX) and much more lightweight
than tree-based parser (DOM), which load the complete tree into memory.
The Reader acts as a cursor going forward on the document stream and stopping
at each node on the way. At every point, the DOM-like methods of the Reader
object allow one to examine the current node (name, namespace, attributes,
etc.)
The user's code keeps control of the progress and simply calls the C<<<<<< read() >>>>>> function repeatedly to progress to the next node in the document order. Other
functions provide means for skipping complete sub-trees, or nodes until a
specific element, etc.
At every time, only a very limited portion of the document is kept in the
memory, which makes the API more memory-efficient than using DOM. However, it
is also possible to mix Reader with DOM. At every point the user may copy the
current node (optionally expanded into a complete sub-tree) from the processed
document to another DOM tree, or to instruct the Reader to collect sub-document
in form of a DOM tree consisting of selected nodes.
Reader API also supports namespaces, xml:base, entity handling, and DTD
validation. Schema and RelaxNG validation support will probably be added in
some later revision of the Perl interface.
The naming of methods compared to libxml2 and C# XmlTextReader has been changed
slightly to match the conventions of XML::LibXML. Some functions have been
changed or added with respect to the C interface.
=head1 CONSTRUCTOR
Depending on the XML source, the Reader object can be created with either of:
my $reader = XML::LibXML::Reader->new( location => "file.xml", ... );
my $reader = XML::LibXML::Reader->new( string => $xml_string, ... );
my $reader = XML::LibXML::Reader->new( IO => $file_handle, ... );
my $reader = XML::LibXML::Reader->new( FD => fileno(STDIN), ... );
my $reader = XML::LibXML::Reader->new( DOM => $dom, ... );
where ... are (optional) reader options described below in L<<<<<< Reader options >>>>>> or various parser options described in L<<<<<< XML::LibXML::Parser >>>>>>. The constructor recognizes the following XML sources:
=head2 Source specification
=over 4
=item location
Read XML from a local file or (non-HTTPS) URL.
=item string
Read XML from a string.
=item IO
Read XML a Perl IO filehandle.
=item FD
Read XML from a file descriptor (bypasses Perl I/O layer, only applicable to
filehandles for regular files or pipes). Possibly faster than IO.
=item DOM
Use reader API to walk through a pre-parsed L<<<<<< XML::LibXML::Document >>>>>>.
=back
=head2 Reader options
=over 4
=item encoding => $encoding
override document encoding.
=item RelaxNG => $rng_schema
can be used to pass either a L<<<<<< XML::LibXML::RelaxNG >>>>>> object or a filename or (non-HTTPS) URL of a RelaxNG schema to the constructor.
The schema is then used to validate the document as it is processed.
=item Schema => $xsd_schema
can be used to pass either a L<<<<<< XML::LibXML::Schema >>>>>> object or a filename or (non-HTTPS) URL of a W3C XSD schema to the constructor.
The schema is then used to validate the document as it is processed.
=item ...
the reader further supports various parser options described in L<<<<<< XML::LibXML::Parser >>>>>> (specifically those labeled by /reader/).
=back
=head1 METHODS CONTROLLING PARSING PROGRESS
=over 4
=item read ()
Moves the position to the next node in the stream, exposing its properties.
Returns 1 if the node was read successfully, 0 if there is no more nodes to
read, or -1 in case of error
=item readAttributeValue ()
Parses an attribute value into one or more Text and EntityReference nodes.
Returns 1 in case of success, 0 if the reader was not positioned on an
attribute node or all the attribute values have been read, or -1 in case of
error.
=item readState ()
Gets the read state of the reader. Returns the state value, or -1 in case of
error. The module exports constants for the Reader states, see STATES below.
=item depth ()
The depth of the node in the tree, starts at 0 for the root node.
=item next ()
Skip to the node following the current one in the document order while avoiding
the sub-tree if any. Returns 1 if the node was read successfully, 0 if there is
no more nodes to read, or -1 in case of error.
=item nextElement (localname?,nsURI?)
Skip nodes following the current one in the document order until a specific
element is reached. The element's name must be equal to a given localname if
defined, and its namespace must equal to a given nsURI if defined. Either of
the arguments can be undefined (or omitted, in case of the latter or both).
Returns 1 if the element was found, 0 if there is no more nodes to read, or -1
in case of error.
=item nextPatternMatch (compiled_pattern)
Skip nodes following the current one in the document order until an element
matching a given compiled pattern is reached. See L<<<<<< XML::LibXML::Pattern >>>>>> for information on compiled patterns. See also the C<<<<<< matchesPattern >>>>>> method.
Returns 1 if the element was found, 0 if there is no more nodes to read, or -1
in case of error.
=item skipSiblings ()
Skip all nodes on the same or lower level until the first node on a higher
level is reached. In particular, if the current node occurs in an element, the
reader stops at the end tag of the parent element, otherwise it stops at a node
immediately following the parent node.
Returns 1 if successful, 0 if end of the document is reached, or -1 in case of
error.
=item nextSibling ()
It skips to the node following the current one in the document order while
avoiding the sub-tree if any.
Returns 1 if the node was read successfully, 0 if there is no more nodes to
read, or -1 in case of error
=item nextSiblingElement (name?,nsURI?)
Like nextElement but only processes sibling elements of the current node
(moving forward using C<<<<<< nextSibling () >>>>>> rather than C<<<<<< read () >>>>>>, internally).
Returns 1 if the element was found, 0 if there is no more sibling nodes, or -1
in case of error.
=item finish ()
Skip all remaining nodes in the document, reaching end of the document.
Returns 1 if successful, 0 in case of error.
=item close ()
This method releases any resources allocated by the current instance and closes
any underlying input. It returns 0 on failure and 1 on success. This method is
automatically called by the destructor when the reader is forgotten, therefore
you do not have to call it directly.
=back
=head1 METHODS EXTRACTING INFORMATION
=over 4
=item name ()
Returns the qualified name of the current node, equal to (Prefix:)LocalName.
=item nodeType ()
Returns the type of the current node. See NODE TYPES below.
=item localName ()
Returns the local name of the node.
=item prefix ()
Returns the prefix of the namespace associated with the node.
=item namespaceURI ()
Returns the URI defining the namespace associated with the node.
=item isEmptyElement ()
Check if the current node is empty, this is a bit bizarre in the sense that
will be considered empty while will not.
=item hasValue ()
Returns true if the node can have a text value.
=item value ()
Provides the text value of the node if present or undef if not available.
=item readInnerXml ()
Reads the contents of the current node, including child nodes and markup.
Returns a string containing the XML of the node's content, or undef if the
current node is neither an element nor attribute, or has no child nodes.
=item readOuterXml ()
Reads the contents of the current node, including child nodes and markup.
Returns a string containing the XML of the node including its content, or undef
if the current node is neither an element nor attribute.
=item nodePath()
Returns a canonical location path to the current element from the root node to
the current node. Namespaced elements are matched by '*', because there is no
way to declare prefixes within XPath patterns. Unlike C<<<<<< XML::LibXML::Node::nodePath() >>>>>>, this function does not provide sibling counts (i.e. instead of e.g. '/a/b[1]'
and '/a/b[2]' you get '/a/b' for both matches).
=item matchesPattern(compiled_pattern)
Returns a true value if the current node matches a compiled pattern. See L<<<<<< XML::LibXML::Pattern >>>>>> for information on compiled patterns. See also the C<<<<<< nextPatternMatch >>>>>> method.
=back
=head1 METHODS EXTRACTING DOM NODES
=over 4
=item document ()
Provides access to the document tree built by the reader. This function can be
used to collect the preserved nodes (see C<<<<<< preserveNode() >>>>>> and preservePattern).
CAUTION: Never use this function to modify the tree unless reading of the whole
document is completed!
=item copyCurrentNode (deep)
This function is similar a DOM function C<<<<<< copyNode() >>>>>>. It returns a copy of the currently processed node as a corresponding DOM
object. Use deep = 1 to obtain the full sub-tree.
=item preserveNode ()
This tells the XML Reader to preserve the current node in the document tree. A
document tree consisting of the preserved nodes and their content can be
obtained using the method C<<<<<< document() >>>>>> once parsing is finished.
Returns the node or NULL in case of error.
=item preservePattern (pattern,\%ns_map)
This tells the XML Reader to preserve all nodes matched by the pattern (which
is a streaming XPath subset). A document tree consisting of the preserved nodes
and their content can be obtained using the method C<<<<<< document() >>>>>> once parsing is finished.
An optional second argument can be used to provide a HASH reference mapping
prefixes used by the XPath to namespace URIs.
The XPath subset available with this function is described at
http://www.w3.org/TR/xmlschema-1/#Selector
and matches the production
Path ::= ('.//')? ( Step '/' )* ( Step | '@' NameTest )
Returns a positive number in case of success and -1 in case of error
=back
=head1 METHODS PROCESSING ATTRIBUTES
=over 4
=item attributeCount ()
Provides the number of attributes of the current node.
=item hasAttributes ()
Whether the node has attributes.
=item getAttribute (name)
Provides the value of the attribute with the specified qualified name.
Returns a string containing the value of the specified attribute, or undef in
case of error.
=item getAttributeNs (localName, namespaceURI)
Provides the value of the specified attribute.
Returns a string containing the value of the specified attribute, or undef in
case of error.
=item getAttributeNo (no)
Provides the value of the attribute with the specified index relative to the
containing element.
Returns a string containing the value of the specified attribute, or undef in
case of error.
=item isDefault ()
Returns true if the current attribute node was generated from the default value
defined in the DTD.
=item moveToAttribute (name)
Moves the position to the attribute with the specified local name and namespace
URI.
Returns 1 in case of success, -1 in case of error, 0 if not found
=item moveToAttributeNo (no)
Moves the position to the attribute with the specified index relative to the
containing element.
Returns 1 in case of success, -1 in case of error, 0 if not found
=item moveToAttributeNs (localName,namespaceURI)
Moves the position to the attribute with the specified local name and namespace
URI.
Returns 1 in case of success, -1 in case of error, 0 if not found
=item moveToFirstAttribute ()
Moves the position to the first attribute associated with the current node.
Returns 1 in case of success, -1 in case of error, 0 if not found
=item moveToNextAttribute ()
Moves the position to the next attribute associated with the current node.
Returns 1 in case of success, -1 in case of error, 0 if not found
=item moveToElement ()
Moves the position to the node that contains the current attribute node.
Returns 1 in case of success, -1 in case of error, 0 if not moved
=item isNamespaceDecl ()
Determine whether the current node is a namespace declaration rather than a
regular attribute.
Returns 1 if the current node is a namespace declaration, 0 if it is a regular
attribute or other type of node, or -1 in case of error.
=back
=head1 OTHER METHODS
=over 4
=item lookupNamespace (prefix)
Resolves a namespace prefix in the scope of the current element.
Returns a string containing the namespace URI to which the prefix maps or undef
in case of error.
=item encoding ()
Returns a string containing the encoding of the document or undef in case of
error.
=item standalone ()
Determine the standalone status of the document being read. Returns 1 if the
document was declared to be standalone, 0 if it was declared to be not
standalone, or -1 if the document did not specify its standalone status or in
case of error.
=item xmlVersion ()
Determine the XML version of the document being read. Returns a string
containing the XML version of the document or undef in case of error.
=item baseURI ()
Returns the base URI of a given node.
=item isValid ()
Retrieve the validity status from the parser.
Returns 1 if valid, 0 if no, and -1 in case of error.
=item xmlLang ()
The xml:lang scope within which the node resides.
=item lineNumber ()
Provide the line number of the current parsing point.
=item columnNumber ()
Provide the column number of the current parsing point.
=item byteConsumed ()
This function provides the current index of the parser relative to the start of
the current entity. This function is computed in bytes from the beginning
starting at zero and finishing at the size in bytes of the file if parsing a
file. The function is of constant cost if the input is UTF-8 but can be costly
if run on non-UTF-8 input.
=item setParserProp (prop => value, ...)
Change the parser processing behaviour by changing some of its internal
properties. The following properties are available with this function:
``load_ext_dtd'', ``complete_attributes'', ``validation'', ``expand_entities''.
Since some of the properties can only be changed before any read has been done,
it is best to set the parsing properties at the constructor.
Returns 0 if the call was successful, or -1 in case of error
=item getParserProp (prop)
Get value of an parser internal property. The following property names can be
used: ``load_ext_dtd'', ``complete_attributes'', ``validation'',
``expand_entities''.
Returns the value, usually 0 or 1, or -1 in case of error.
=back
=head1 DESTRUCTION
XML::LibXML takes care of the reader object destruction when the last reference
to the reader object goes out of scope. The document tree is preserved, though,
if either of $reader->document or $reader->preserveNode was used and references
to the document tree exist.
=head1 NODE TYPES
The reader interface provides the following constants for node types (the
constant symbols are exported by default or if tag C<<<<<< :types >>>>>> is used).
XML_READER_TYPE_NONE => 0
XML_READER_TYPE_ELEMENT => 1
XML_READER_TYPE_ATTRIBUTE => 2
XML_READER_TYPE_TEXT => 3
XML_READER_TYPE_CDATA => 4
XML_READER_TYPE_ENTITY_REFERENCE => 5
XML_READER_TYPE_ENTITY => 6
XML_READER_TYPE_PROCESSING_INSTRUCTION => 7
XML_READER_TYPE_COMMENT => 8
XML_READER_TYPE_DOCUMENT => 9
XML_READER_TYPE_DOCUMENT_TYPE => 10
XML_READER_TYPE_DOCUMENT_FRAGMENT => 11
XML_READER_TYPE_NOTATION => 12
XML_READER_TYPE_WHITESPACE => 13
XML_READER_TYPE_SIGNIFICANT_WHITESPACE => 14
XML_READER_TYPE_END_ELEMENT => 15
XML_READER_TYPE_END_ENTITY => 16
XML_READER_TYPE_XML_DECLARATION => 17
=head1 STATES
The following constants represent the values returned by C<<<<<< readState() >>>>>>. They are exported by default, or if tag C<<<<<< :states >>>>>> is used:
XML_READER_NONE => -1
XML_READER_START => 0
XML_READER_ELEMENT => 1
XML_READER_END => 2
XML_READER_EMPTY => 3
XML_READER_BACKTRACK => 4
XML_READER_DONE => 5
XML_READER_ERROR => 6
=head1 SEE ALSO
L<<<<<< XML::LibXML::Pattern >>>>>> for information about compiled patterns.
http://xmlsoft.org/html/libxml-xmlreader.html
http://dotgnu.org/pnetlib-doc/System/Xml/XmlTextReader.html
=head1 ORIGINAL IMPLEMENTATION
Heiko Klein, and Petr Pajas
=head1 AUTHORS
Matt Sergeant,
Christian Glahn,
Petr Pajas
=head1 VERSION
2.0213
=head1 COPYRIGHT
2001-2007, AxKit.com Ltd.
2002-2006, Christian Glahn.
2006-2009, Petr Pajas.
=cut
=head1 LICENSE
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
Parser.pod 0000444 00000067445 15234477232 0006533 0 ustar 00 =head1 NAME
XML::LibXML::Parser - Parsing XML Data with XML::LibXML
=head1 SYNOPSIS
use XML::LibXML '1.70';
# Parser constructor
$parser = XML::LibXML->new();
$parser = XML::LibXML->new(option=>value, ...);
$parser = XML::LibXML->new({option=>value, ...});
# Parsing XML
$dom = XML::LibXML->load_xml(
location => $file_or_url
# parser options ...
);
$dom = XML::LibXML->load_xml(
string => $xml_string
# parser options ...
);
$dom = XML::LibXML->load_xml(
string => (\$xml_string)
# parser options ...
);
$dom = XML::LibXML->load_xml({
IO => $perl_file_handle
# parser options ...
);
$dom = $parser->load_xml(...);
# Parsing HTML
$dom = XML::LibXML->load_html(...);
$dom = $parser->load_html(...);
# Parsing well-balanced XML chunks
$fragment = $parser->parse_balanced_chunk( $wbxmlstring, $encoding );
# Processing XInclude
$parser->process_xincludes( $doc );
$parser->processXIncludes( $doc );
# Old-style parser interfaces
$doc = $parser->parse_file( $xmlfilename );
$doc = $parser->parse_fh( $io_fh );
$doc = $parser->parse_string( $xmlstring);
$doc = $parser->parse_html_file( $htmlfile, \%opts );
$doc = $parser->parse_html_fh( $io_fh, \%opts );
$doc = $parser->parse_html_string( $htmlstring, \%opts );
# Push parser
$parser->parse_chunk($string, $terminate);
$parser->init_push();
$parser->push(@data);
$doc = $parser->finish_push( $recover );
# Set/query parser options
$parser->option_exists($name);
$parser->get_option($name);
$parser->set_option($name,$value);
$parser->set_options({$name=>$value,...});
# XML catalogs
$parser->load_catalog( $catalog_file );
=head1 PARSING
An XML document is read into a data structure such as a DOM tree by a piece of
software, called a parser. XML::LibXML currently provides four different parser
interfaces:
=over 4
=item *
A DOM Pull-Parser
=item *
A DOM Push-Parser
=item *
A SAX Parser
=item *
A DOM based SAX Parser.
=back
=head2 Creating a Parser Instance
XML::LibXML provides an OO interface to the libxml2 parser functions. Thus you
have to create a parser instance before you can parse any XML data.
=over 4
=item new
$parser = XML::LibXML->new();
$parser = XML::LibXML->new(option=>value, ...);
$parser = XML::LibXML->new({option=>value, ...});
Create a new XML and HTML parser instance. Each parser instance holds default
values for various parser options. Optionally, one can pass a hash reference or
a list of option => value pairs to set a different default set of options.
Unless specified otherwise, the options C<<<<<< load_ext_dtd >>>>>>, and C<<<<<< expand_entities >>>>>> are set to 1. See L<<<<<< Parser Options >>>>>> for a list of libxml2 parser's options.
=back
=head2 DOM Parser
One of the common parser interfaces of XML::LibXML is the DOM parser. This
parser reads XML data into a DOM like data structure, so each tag can get
accessed and transformed.
XML::LibXML's DOM parser is not only capable to parse XML data, but also
(strict) HTML files. There are three ways to parse documents - as a string, as
a Perl filehandle, or as a filename/URL. The return value from each is a L<<<<<< XML::LibXML::Document >>>>>> object, which is a DOM object.
All of the functions listed below will throw an exception if the document is
invalid. To prevent this causing your program exiting, wrap the call in an
eval{} block
=over 4
=item load_xml
$dom = XML::LibXML->load_xml(
location => $file_or_url
# parser options ...
);
$dom = XML::LibXML->load_xml(
string => $xml_string
# parser options ...
);
$dom = XML::LibXML->load_xml(
string => (\$xml_string)
# parser options ...
);
$dom = XML::LibXML->load_xml({
IO => $perl_file_handle
# parser options ...
);
$dom = $parser->load_xml(...);
This function is available since XML::LibXML 1.70. It provides easy to use
interface to the XML parser that parses given file (or non-HTTPS URL), string,
or input stream to a DOM tree. The arguments can be passed in a HASH reference
or as name => value pairs. The function can be called as a class method or an
object method. In both cases it internally creates a new parser instance
passing the specified parser options; if called as an object method, it clones
the original parser (preserving its settings) and additionally applies the
specified options to the new parser. See the constructor C<<<<<< new >>>>>> and L<<<<<< Parser Options >>>>>> for more information.
Note that, due to a limitation in the underlying libxml2 library, this call
does not recognize HTTPS-based URLs. (It will treat an HTTPS URL as a filename,
likely throwing a "No such file or directory" exception.)
=item load_html
$dom = XML::LibXML->load_html(...);
$dom = $parser->load_html(...);
This function is available since XML::LibXML 1.70. It has the same usage as C<<<<<< load_xml >>>>>>, providing interface to the HTML parser. See C<<<<<< load_xml >>>>>> for more information.
=back
Parsing HTML may cause problems, especially if the ampersand ('&') is used.
This is a common problem if HTML code is parsed that contains links to
CGI-scripts. Such links cause the parser to throw errors. In such cases libxml2
still parses the entire document as there was no error, but the error causes
XML::LibXML to stop the parsing process. However, the document is not lost.
Such HTML documents should be parsed using the I<<<<<< recover >>>>>> flag. By default recovering is deactivated.
The functions described above are implemented to parse well formed documents.
In some cases a program gets well balanced XML instead of well formed documents
(e.g. an XML fragment from a database). With XML::LibXML it is not required to
wrap such fragments in the code, because XML::LibXML is capable even to parse
well balanced XML fragments.
=over 4
=item parse_balanced_chunk
$fragment = $parser->parse_balanced_chunk( $wbxmlstring, $encoding );
This function parses a well balanced XML string into a L<<<<<< XML::LibXML::DocumentFragment >>>>>>. The first arguments contains the input string, the optional second argument
can be used to specify character encoding of the input (UTF-8 is assumed by
default).
=item parse_xml_chunk
This is the old name of parse_balanced_chunk(). Because it may causes confusion
with the push parser interface, this function should not be used anymore.
=back
By default XML::LibXML does not process XInclude tags within an XML Document
(see options section below). XML::LibXML allows one to post-process a document
to expand XInclude tags.
=over 4
=item process_xincludes
$parser->process_xincludes( $doc );
After a document is parsed into a DOM structure, you may want to expand the
documents XInclude tags. This function processes the given document structure
and expands all XInclude tags (or throws an error) by using the flags and
callbacks of the given parser instance.
Note that the resulting Tree contains some extra nodes (of type
XML_XINCLUDE_START and XML_XINCLUDE_END) after successfully processing the
document. These nodes indicate where data was included into the original tree.
if the document is serialized, these extra nodes will not show up.
Remember: A Document with processed XIncludes differs from the original
document after serialization, because the original XInclude tags will not get
restored!
If the parser flag "expand_xincludes" is set to 1, you need not to post process
the parsed document.
=item processXIncludes
$parser->processXIncludes( $doc );
This is an alias to process_xincludes, but through a JAVA like function name.
=item parse_file
$doc = $parser->parse_file( $xmlfilename );
This function parses an XML document from a file or network; $xmlfilename can
be either a filename or a (non-HTTPS) URL. Note that for parsing files, this
function is the fastest choice, about 6-8 times faster then parse_fh().
=item parse_fh
$doc = $parser->parse_fh( $io_fh );
parse_fh() parses a IOREF or a subclass of IO::Handle.
Because the data comes from an open handle, libxml2's parser does not know
about the base URI of the document. To set the base URI one should use
parse_fh() as follows:
my $doc = $parser->parse_fh( $io_fh, $baseuri );
=item parse_string
$doc = $parser->parse_string( $xmlstring);
This function is similar to parse_fh(), but it parses an XML document that is
available as a single string in memory, or alternatively as a reference to a
scalar containing a string. Again, you can pass an optional base URI to the
function.
my $doc = $parser->parse_string( $xmlstring, $baseuri );
my $doc = $parser->parse_string(\$xmlstring, $baseuri);
=item parse_html_file
$doc = $parser->parse_html_file( $htmlfile, \%opts );
Similar to parse_file() but parses HTML (strict) documents; $htmlfile can be
filename or (non-HTTPS) URL.
An optional second argument can be used to pass some options to the HTML parser
as a HASH reference. See options labeled with HTML in L<<<<<< Parser Options >>>>>>.
=item parse_html_fh
$doc = $parser->parse_html_fh( $io_fh, \%opts );
Similar to parse_fh() but parses HTML (strict) streams.
An optional second argument can be used to pass some options to the HTML parser
as a HASH reference. See options labeled with HTML in L<<<<<< Parser Options >>>>>>.
Note: encoding option may not work correctly with this function in libxml2 <
2.6.27 if the HTML file declares charset using a META tag.
=item parse_html_string
$doc = $parser->parse_html_string( $htmlstring, \%opts );
Similar to parse_string() but parses HTML (strict) strings.
An optional second argument can be used to pass some options to the HTML parser
as a HASH reference. See options labeled with HTML in L<<<<<< Parser Options >>>>>>.
=back
=head2 Push Parser
XML::LibXML provides a push parser interface. Rather than pulling the data from
a given source the push parser waits for the data to be pushed into it.
This allows one to parse large documents without waiting for the parser to
finish. The interface is especially useful if a program needs to pre-process
the incoming pieces of XML (e.g. to detect document boundaries).
While XML::LibXML parse_*() functions force the data to be a well-formed XML,
the push parser will take any arbitrary string that contains some XML data. The
only requirement is that all the pushed strings are together a well formed
document. With the push parser interface a program can interrupt the parsing
process as required, where the parse_*() functions give not enough flexibility.
Different to the pull parser implemented in parse_fh() or parse_file(), the
push parser is not able to find out about the documents end itself. Thus the
calling program needs to indicate explicitly when the parsing is done.
In XML::LibXML this is done by a single function:
=over 4
=item parse_chunk
$parser->parse_chunk($string, $terminate);
parse_chunk() tries to parse a given chunk of data, which isn't necessarily
well balanced data. The function takes two parameters: The chunk of data as a
string and optional a termination flag. If the termination flag is set to a
true value (e.g. 1), the parsing will be stopped and the resulting document
will be returned as the following example describes:
my $parser = XML::LibXML->new;
for my $string ( "<", "foo", ' bar="hello world"', "/>") {
$parser->parse_chunk( $string );
}
my $doc = $parser->parse_chunk("", 1); # terminate the parsing
=back
Internally XML::LibXML provides three functions that control the push parser
process:
=over 4
=item init_push
$parser->init_push();
Initializes the push parser.
=item push
$parser->push(@data);
This function pushes the data stored inside the array to libxml2's parser. Each
entry in @data must be a normal scalar! This method can be called repeatedly.
=item finish_push
$doc = $parser->finish_push( $recover );
This function returns the result of the parsing process. If this function is
called without a parameter it will complain about non well-formed documents. If
$restore is 1, the push parser can be used to restore broken or non well formed
(XML) documents as the following example shows:
eval {
$parser->push( "", "bar" );
$doc = $parser->finish_push(); # will report broken XML
};
if ( $@ ) {
# ...
}
This can be annoying if the closing tag is missed by accident. The following
code will restore the document:
eval {
$parser->push( "", "bar" );
$doc = $parser->finish_push(1); # will return the data parsed
# unless an error happened
};
print $doc->toString(); # returns "bar"
Of course finish_push() will return nothing if there was no data pushed to the
parser before.
=back
=head2 Pull Parser (Reader)
XML::LibXML also provides a pull-parser interface similar to the XmlReader
interface in .NET. This interface is almost streaming, and is usually faster
and simpler to use than SAX. See L<<<<<< XML::LibXML::Reader >>>>>>.
=head2 Direct SAX Parser
XML::LibXML provides a direct SAX parser in the L<<<<<< XML::LibXML::SAX >>>>>> module.
=head2 DOM based SAX Parser
XML::LibXML also provides a DOM based SAX parser. The SAX parser is defined in
the module XML::LibXML::SAX::Parser. As it is not a stream based parser, it
parses documents into a DOM and traverses the DOM tree instead.
The API of this parser is exactly the same as any other Perl SAX2 parser. See
XML::SAX::Intro for details.
Aside from the regular parsing methods, you can access the DOM tree traverser
directly, using the generate() method:
my $doc = build_yourself_a_document();
my $saxparser = $XML::LibXML::SAX::Parser->new( ... );
$parser->generate( $doc );
This is useful for serializing DOM trees, for example that you might have done
prior processing on, or that you have as a result of XSLT processing.
I<<<<<< WARNING >>>>>>
This is NOT a streaming SAX parser. As I said above, this parser reads the
entire document into a DOM and serialises it. Some people couldn't read that in
the paragraph above so I've added this warning. If you want a streaming SAX
parser look at the L<<<<<< XML::LibXML::SAX >>>>>> man page
=head1 SERIALIZATION
XML::LibXML provides some functions to serialize nodes and documents. The
serialization functions are described on the L<<<<<< XML::LibXML::Node >>>>>> manpage or the L<<<<<< XML::LibXML::Document >>>>>> manpage. XML::LibXML checks three global flags that alter the serialization
process:
=over 4
=item *
skipXMLDeclaration
=item *
skipDTD
=item *
setTagCompression
=back
of that three functions only setTagCompression is available for all
serialization functions.
Because XML::LibXML does these flags not itself, one has to define them locally
as the following example shows:
local $XML::LibXML::skipXMLDeclaration = 1;
local $XML::LibXML::skipDTD = 1;
local $XML::LibXML::setTagCompression = 1;
If skipXMLDeclaration is defined and not '0', the XML declaration is omitted
during serialization.
If skipDTD is defined and not '0', an existing DTD would not be serialized with
the document.
If setTagCompression is defined and not '0' empty tags are displayed as open
and closing tags rather than the shortcut. For example the empty tag I<<<<<< foo >>>>>> will be rendered as I<<<<<< EfooEE/fooE >>>>>> rather than I<<<<<< Efoo/E >>>>>>.
=head1 PARSER OPTIONS
Handling of libxml2 parser options has been unified and improved in XML::LibXML
1.70. You can now set default options for a particular parser instance by
passing them to the constructor as C<<<<<< XML::LibXML-Enew({name=Evalue, ...}) >>>>>> or C<<<<<< XML::LibXML-Enew(name=Evalue,...) >>>>>>. The options can be queried and changed using the following methods (pre-1.70
interfaces such as C<<<<<< $parser-Eload_ext_dtd(0) >>>>>> also exist, see below):
=over 4
=item option_exists
$parser->option_exists($name);
Returns 1 if the current XML::LibXML version supports the option C<<<<<< $name >>>>>>, otherwise returns 0 (note that this does not necessarily mean that the option
is supported by the underlying libxml2 library).
=item get_option
$parser->get_option($name);
Returns the current value of the parser option C<<<<<< $name >>>>>>.
=item set_option
$parser->set_option($name,$value);
Sets option C<<<<<< $name >>>>>> to value C<<<<<< $value >>>>>>.
=item set_options
$parser->set_options({$name=>$value,...});
Sets multiple parsing options at once.
=back
IMPORTANT NOTE: This documentation reflects the parser flags available in
libxml2 2.7.3. Some options have no effect if an older version of libxml2 is
used.
Each of the flags listed below is labeled
=over 4
=item /parser/
if it can be used with a C<<<<<< XML::LibXML >>>>>> parser object (i.e. passed to C<<<<<< XML::LibXML-Enew >>>>>>, C<<<<<< XML::LibXML-Eset_option >>>>>>, etc.)
=item /html/
if it can be used passed to the C<<<<<< parse_html_* >>>>>> methods
=item /reader/
if it can be used with the C<<<<<< XML::LibXML::Reader >>>>>>.
=back
Unless specified otherwise, the default for boolean valued options is 0
(false).
The available options are:
=over 4
=item URI
/parser, html, reader/
In case of parsing strings or file handles, XML::LibXML doesn't know about the
base uri of the document. To make relative references such as XIncludes work,
one has to set a base URI, that is then used for the parsed document.
=item line_numbers
/parser, html, reader/
If this option is activated, libxml2 will store the line number of each element
node in the parsed document. The line number can be obtained using the C<<<<<< line_number() >>>>>> method of the C<<<<<< XML::LibXML::Node >>>>>> class (for non-element nodes this may report the line number of the containing
element). The line numbers are also used for reporting positions of validation
errors.
IMPORTANT: Due to limitations in the libxml2 library line numbers greater than
65535 will be returned as 65535. Unfortunately, this is a long and sad story,
please see L<<<<<< http://bugzilla.gnome.org/show_bug.cgi?id=325533 >>>>>> for more details.
=item encoding
/html/
character encoding of the input
=item recover
/parser, html, reader/
recover from errors; possible values are 0, 1, and 2
A true value turns on recovery mode which allows one to parse broken XML or
HTML data. The recovery mode allows the parser to return the successfully
parsed portion of the input document. This is useful for almost well-formed
documents, where for example a closing tag is missing somewhere. Still,
XML::LibXML will only parse until the first fatal (non-recoverable) error
occurs, reporting recoverable parsing errors as warnings. To suppress even
these warnings, use recover=>2.
Note that validation is switched off automatically in recovery mode.
=item expand_entities
/parser, reader/
substitute entities; possible values are 0 and 1; default is 1
Note that although this flag disables entity substitution, it does not prevent
the parser from loading external entities; when substitution of an external
entity is disabled, the entity will be represented in the document tree by an
XML_ENTITY_REF_NODE node whose subtree will be the content obtained by parsing
the external resource; Although this nesting is visible from the DOM it is
transparent to XPath data model, so it is possible to match nodes in an
unexpanded entity by the same XPath expression as if the entity were expanded.
See also ext_ent_handler.
=item ext_ent_handler
/parser/
Provide a custom external entity handler to be used when expand_entities is set
to 1. Possible value is a subroutine reference.
This feature does not work properly in libxml2 < 2.6.27!
The subroutine provided is called whenever the parser needs to retrieve the
content of an external entity. It is called with two arguments: the system ID
(URI) and the public ID. The value returned by the subroutine is parsed as the
content of the entity.
This method can be used to completely disable entity loading, e.g. to prevent
exploits of the type described at (L<<<<<< http://searchsecuritychannel.techtarget.com/generic/0,295582,sid97_gci1304703,00.html >>>>>>), where a service is tricked to expose its private data by letting it parse a
remote file (RSS feed) that contains an entity reference to a local file (e.g. C<<<<<< /etc/fstab >>>>>>).
A more granular solution to this problem, however, is provided by custom URL
resolvers, as in
my $c = XML::LibXML::InputCallback->new();
sub match { # accept file:/ URIs except for XML catalogs in /etc/xml/
my ($uri) = @_;
return ($uri=~m{^file:/}
and $uri !~ m{^file:///etc/xml/})
? 1 : 0;
}
$c->register_callbacks([ \&match, sub{}, sub{}, sub{} ]);
$parser->input_callbacks($c);
=item load_ext_dtd
/parser, reader/
load the external DTD subset while parsing; possible values are 0 and 1. Unless
specified, XML::LibXML sets this option to 1.
This flag is also required for DTD Validation, to provide complete attribute,
and to expand entities, regardless if the document has an internal subset. Thus
switching off external DTD loading, will disable entity expansion, validation,
and complete attributes on internal subsets as well.
=item complete_attributes
/parser, reader/
create default DTD attributes; possible values are 0 and 1
=item validation
/parser, reader/
validate with the DTD; possible values are 0 and 1
=item suppress_errors
/parser, html, reader/
suppress error reports; possible values are 0 and 1
=item suppress_warnings
/parser, html, reader/
suppress warning reports; possible values are 0 and 1
=item pedantic_parser
/parser, html, reader/
pedantic error reporting; possible values are 0 and 1
=item no_blanks
/parser, html, reader/
remove blank nodes; possible values are 0 and 1
=item no_defdtd
/html/
do not add a default DOCTYPE; possible values are 0 and 1
the default is (0) to add a DTD when the input html lacks one
=item expand_xinclude or xinclude
/parser, reader/
Implement XInclude substitution; possible values are 0 and 1
Expands XInclude tags immediately while parsing the document. Note that the
parser will use the URI resolvers installed via C<<<<<< XML::LibXML::InputCallback >>>>>> to parse the included document (if any).
=item no_xinclude_nodes
/parser, reader/
do not generate XINCLUDE START/END nodes; possible values are 0 and 1
=item no_network
/parser, html, reader/
Forbid network access; possible values are 0 and 1
If set to true, all attempts to fetch non-local resources (such as DTD or
external entities) will fail (unless custom callbacks are defined).
It may be necessary to use the flag C<<<<<< recover >>>>>> for processing documents requiring such resources while networking is off.
=item clean_namespaces
/parser, reader/
remove redundant namespaces declarations during parsing; possible values are 0
and 1.
=item no_cdata
/parser, html, reader/
merge CDATA as text nodes; possible values are 0 and 1
=item no_basefix
/parser, reader/
not fixup XINCLUDE xml#base URIS; possible values are 0 and 1
=item huge
/parser, html, reader/
relax any hardcoded limit from the parser; possible values are 0 and 1. Unless
specified, XML::LibXML sets this option to 0.
Note: the default value for this option was changed to protect against denial
of service through entity expansion attacks. Before enabling the option ensure
you have taken alternative measures to protect your application against this
type of attack.
=item gdome
/parser/
THIS OPTION IS EXPERIMENTAL!
Although quite powerful, XML::LibXML's DOM implementation is incomplete with
respect to the DOM level 2 or level 3 specifications. XML::GDOME is based on
libxml2 as well, and provides a rather complete DOM implementation by wrapping
libgdome. This flag allows you to make use of XML::LibXML's full parser options
and XML::GDOME's DOM implementation at the same time.
To make use of this function, one has to install libgdome and configure
XML::LibXML to use this library. For this you need to rebuild XML::LibXML!
Note: this feature was not seriously tested in recent XML::LibXML releases.
=back
For compatibility with XML::LibXML versions prior to 1.70, the following
methods are also supported for querying and setting the corresponding parser
options (if called without arguments, the methods return the current value of
the corresponding parser options; with an argument sets the option to a given
value):
$parser->validation();
$parser->recover();
$parser->pedantic_parser();
$parser->line_numbers();
$parser->load_ext_dtd();
$parser->complete_attributes();
$parser->expand_xinclude();
$parser->gdome_dom();
$parser->clean_namespaces();
$parser->no_network();
The following obsolete methods trigger parser options in some special way:
=over 4
=item recover_silently
$parser->recover_silently(1);
If called without an argument, returns true if the current value of the C<<<<<< recover >>>>>> parser option is 2 and returns false otherwise. With a true argument sets the C<<<<<< recover >>>>>> parser option to 2; with a false argument sets the C<<<<<< recover >>>>>> parser option to 0.
=item expand_entities
$parser->expand_entities(0);
Get/set the C<<<<<< expand_entities >>>>>> option. If called with a true argument, also turns the C<<<<<< load_ext_dtd >>>>>> option to 1.
=item keep_blanks
$parser->keep_blanks(0);
This is actually the opposite of the C<<<<<< no_blanks >>>>>> parser option. If used without an argument retrieves negated value of C<<<<<< no_blanks >>>>>>. If used with an argument sets C<<<<<< no_blanks >>>>>> to the opposite value.
=item base_uri
$parser->base_uri( $your_base_uri );
Get/set the C<<<<<< URI >>>>>> option.
=back
=head1 XML CATALOGS
C<<<<<< libxml2 >>>>>> supports XML catalogs. Catalogs are used to map remote resources to their local
copies. Using catalogs can speed up parsing processes if many external
resources from remote addresses are loaded into the parsed documents (such as
DTDs or XIncludes).
Note that libxml2 has a global pool of loaded catalogs, so if you apply the
method C<<<<<< load_catalog >>>>>> to one parser instance, all parser instances will start using the catalog (in
addition to other previously loaded catalogs).
Note also that catalogs are not used when a custom external entity handler is
specified. At the current state it is not possible to make use of both types of
resolving systems at the same time.
=over 4
=item load_catalog
$parser->load_catalog( $catalog_file );
Loads the XML catalog file $catalog_file.
# Global external entity loader (similar to ext_ent_handler option
# but this works really globally, also in XML::LibXSLT include etc..)
XML::LibXML::externalEntityLoader(\&my_loader);
=back
=head1 ERROR REPORTING
XML::LibXML throws exceptions during parsing, validation or XPath processing
(and some other occasions). These errors can be caught by using I<<<<<< eval >>>>>> blocks. The error is stored in I<<<<<< $@ >>>>>>. There are two implementations: the old one throws $@ which is just a message
string, in the new one $@ is an object from the class XML::LibXML::Error; this
class overrides the operator "" so that when printed, the object flattens to
the usual error message.
XML::LibXML throws errors as they occur. This is a very common misunderstanding
in the use of XML::LibXML. If the eval is omitted, XML::LibXML will always halt
your script by "croaking" (see Carp man page for details).
Also note that an increasing number of functions throw errors if bad data is
passed as arguments. If you cannot assure valid data passed to XML::LibXML you
should eval these functions.
Note: since version 1.59, get_last_error() is no longer available in
XML::LibXML for thread-safety reasons.
=head1 AUTHORS
Matt Sergeant,
Christian Glahn,
Petr Pajas
=head1 VERSION
2.0213
=head1 COPYRIGHT
2001-2007, AxKit.com Ltd.
2002-2006, Christian Glahn.
2006-2009, Petr Pajas.
=cut
=head1 LICENSE
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
InputCallback.pod 0000444 00000023136 15234477232 0010000 0 ustar 00 =head1 NAME
XML::LibXML::InputCallback - XML::LibXML Class for Input Callbacks
=head1 SYNOPSIS
use XML::LibXML;
=head1 DESCRIPTION
You may get unexpected results if you are trying to load external documents
during libxml2 parsing if the location of the resource is not a HTTP, FTP or
relative location but a absolute path for example. To get around this
limitation, you may add your own input handler to open, read and close
particular types of locations or URI classes. Using this input callback
handlers, you can handle your own custom URI schemes for example.
The input callbacks are used whenever XML::LibXML has to get something other
than externally parsed entities from somewhere. They are implemented using a
callback stack on the Perl layer in analogy to libxml2's native callback stack.
The XML::LibXML::InputCallback class transparently registers the input
callbacks for the libxml2's parser processes.
=head2 How does XML::LibXML::InputCallback work?
The libxml2 library offers a callback implementation as global functions only.
To work-around the troubles resulting in having only global callbacks - for
example, if the same global callback stack is manipulated by different
applications running together in a single Apache Web-server environment -,
XML::LibXML::InputCallback comes with a object-oriented and a function-oriented
part.
Using the function-oriented part the global callback stack of libxml2 can be
manipulated. Those functions can be used as interface to the callbacks on the
C- and XS Layer. At the object-oriented part, operations for working with the
"pseudo-localized" callback stack are implemented. Currently, you can register
and de-register callbacks on the Perl layer and initialize them on a per parser
basis.
=head3 Callback Groups
The libxml2 input callbacks come in groups. One group contains a URI matcher (I<<<<<< match >>>>>>), a data stream constructor (I<<<<<< open >>>>>>), a data stream reader (I<<<<<< read >>>>>>), and a data stream destructor (I<<<<<< close >>>>>>). The callbacks can be manipulated on a per group basis only.
=head3 The Parser Process
The parser process works on an XML data stream, along which, links to other
resources can be embedded. This can be links to external DTDs or XIncludes for
example. Those resources are identified by URIs. The callback implementation of
libxml2 assumes that one callback group can handle a certain amount of URIs and
a certain URI scheme. Per default, callback handlers for I<<<<<< file://* >>>>>>, I<<<<<< file:://*.gz >>>>>>, I<<<<<< http://* >>>>>> and I<<<<<< ftp://* >>>>>> are registered.
Callback groups in the callback stack are processed from top to bottom, meaning
that callback groups registered later will be processed before the earlier
registered ones.
While parsing the data stream, the libxml2 parser checks if a registered
callback group will handle a URI - if they will not, the URI will be
interpreted as I<<<<<< file://URI >>>>>>. To handle a URI, the I<<<<<< match >>>>>> callback will have to return '1'. If that happens, the handling of the URI will
be passed to that callback group. Next, the URI will be passed to the I<<<<<< open >>>>>> callback, which should return a I<<<<<< reference >>>>>> to the data stream if it successfully opened the file, '0' otherwise. If
opening the stream was successful, the I<<<<<< read >>>>>> callback will be called repeatedly until it returns an empty string. After the
read callback, the I<<<<<< close >>>>>> callback will be called to close the stream.
=head3 Organisation of callback groups in XML::LibXML::InputCallback
Callback groups are implemented as a stack (Array), each entry holds a
reference to an array of the callbacks. For the libxml2 library, the
XML::LibXML::InputCallback callback implementation appears as one single
callback group. The Perl implementation however allows one to manage different
callback stacks on a per libxml2-parser basis.
=head2 Using XML::LibXML::InputCallback
After object instantiation using the parameter-less constructor, you can
register callback groups.
my $input_callbacks = XML::LibXML::InputCallback->new();
$input_callbacks->register_callbacks([ $match_cb1, $open_cb1,
$read_cb1, $close_cb1 ] );
$input_callbacks->register_callbacks([ $match_cb2, $open_cb2,
$read_cb2, $close_cb2 ] );
$input_callbacks->register_callbacks( [ $match_cb3, $open_cb3,
$read_cb3, $close_cb3 ] );
$parser->input_callbacks( $input_callbacks );
$parser->parse_file( $some_xml_file );
=head2 What about the old callback system prior to XML::LibXML::InputCallback?
In XML::LibXML versions prior to 1.59 - i.e. without the
XML::LibXML::InputCallback module - you could define your callbacks either
using globally or locally. You still can do that using
XML::LibXML::InputCallback, and in addition to that you can define the
callbacks on a per parser basis!
If you use the old callback interface through global callbacks,
XML::LibXML::InputCallback will treat them with a lower priority as the ones
registered using the new interface. The global callbacks will not override the
callback groups registered using the new interface. Local callbacks are
attached to a specific parser instance, therefore they are treated with highest
priority. If the I<<<<<< match >>>>>> callback of the callback group registered as local variable is identical to one
of the callback groups registered using the new interface, that callback group
will be replaced.
Users of the old callback implementation whose I<<<<<< open >>>>>> callback returned a plain string, will have to adapt their code to return a
reference to that string after upgrading to version >= 1.59. The new callback
system can only deal with the I<<<<<< open >>>>>> callback returning a reference!
=head1 INTERFACE DESCRIPTION
=head2 Global Variables
=over 4
=item $_CUR_CB
Stores the current callback and can be used as shortcut to access the callback
stack.
=item @_GLOBAL_CALLBACKS
Stores all callback groups for the current parser process.
=item @_CB_STACK
Stores the currently used callback group. Used to prevent parser errors when
dealing with nested XML data.
=back
=head2 Global Callbacks
=over 4
=item _callback_match
Implements the interface for the I<<<<<< match >>>>>> callback at C-level and for the selection of the callback group from the
callbacks defined at the Perl-level.
=item _callback_open
Forwards the I<<<<<< open >>>>>> callback from libxml2 to the corresponding callback function at the Perl-level.
=item _callback_read
Forwards the read request to the corresponding callback function at the
Perl-level and returns the result to libxml2.
=item _callback_close
Forwards the I<<<<<< close >>>>>> callback from libxml2 to the corresponding callback function at the
Perl-level..
=back
=head2 Class methods
=over 4
=item new()
A simple constructor.
=item register_callbacks( [ $match_cb, $open_cb, $read_cb, $close_cb ])
The four callbacks I<<<<<< have >>>>>> to be given as array reference in the above order I<<<<<< match >>>>>>, I<<<<<< open >>>>>>, I<<<<<< read >>>>>>, I<<<<<< close >>>>>>!
=item unregister_callbacks( [ $match_cb, $open_cb, $read_cb, $close_cb ])
With no arguments given, C<<<<<< unregister_callbacks() >>>>>> will delete the last registered callback group from the stack. If four
callbacks are passed as array reference, the callback group to unregister will
be identified by the I<<<<<< match >>>>>> callback and deleted from the callback stack. Note that if several identical I<<<<<< match >>>>>> callbacks are defined in different callback groups, ALL of them will be deleted
from the stack.
=item init_callbacks( $parser )
Initializes the callback system for the provided parser before starting a
parsing process.
=item cleanup_callbacks()
Resets global variables and the libxml2 callback stack.
=item lib_init_callbacks()
Used internally for callback registration at C-level.
=item lib_cleanup_callbacks()
Used internally for callback resetting at the C-level.
=back
=head1 EXAMPLE CALLBACKS
The following example is a purely fictitious example that uses a
MyScheme::Handler object that responds to methods similar to an IO::Handle.
# Define the four callback functions
sub match_uri {
my $uri = shift;
return $uri =~ /^myscheme:/; # trigger our callback group at a 'myscheme' URIs
}
sub open_uri {
my $uri = shift;
my $handler = MyScheme::Handler->new($uri);
return $handler;
}
# The returned $buffer will be parsed by the libxml2 parser
sub read_uri {
my $handler = shift;
my $length = shift;
my $buffer;
read($handler, $buffer, $length);
return $buffer; # $buffer will be an empty string '' if read() is done
}
# Close the handle associated with the resource.
sub close_uri {
my $handler = shift;
close($handler);
}
# Register them with a instance of XML::LibXML::InputCallback
my $input_callbacks = XML::LibXML::InputCallback->new();
$input_callbacks->register_callbacks([ \&match_uri, \&open_uri,
\&read_uri, \&close_uri ] );
# Register the callback group at a parser instance
$parser->input_callbacks( $input_callbacks );
# $some_xml_file will be parsed using our callbacks
$parser->parse_file( $some_xml_file );
=head1 AUTHORS
Matt Sergeant,
Christian Glahn,
Petr Pajas
=head1 VERSION
2.0213
=head1 COPYRIGHT
2001-2007, AxKit.com Ltd.
2002-2006, Christian Glahn.
2006-2009, Petr Pajas.
=cut
=head1 LICENSE
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
Document.pod 0000444 00000052205 15234477232 0007041 0 ustar 00 =head1 NAME
XML::LibXML::Document - XML::LibXML DOM Document Class
=head1 SYNOPSIS
use XML::LibXML;
# Only methods specific to Document nodes are listed here,
# see the XML::LibXML::Node manpage for other methods
$dom = XML::LibXML::Document->new( $version, $encoding );
$dom = XML::LibXML::Document->createDocument( $version, $encoding );
$strURI = $doc->URI();
$doc->setURI($strURI);
$strEncoding = $doc->encoding();
$strEncoding = $doc->actualEncoding();
$doc->setEncoding($new_encoding);
$strVersion = $doc->version();
$doc->standalone
$doc->setStandalone($numvalue);
my $compression = $doc->compression;
$doc->setCompression($ziplevel);
$docstring = $dom->toString($format);
$c14nstr = $doc->toStringC14N($comment_flag, $xpath_expression [, $xpath_context ]);
$ec14nstr = $doc->toStringEC14N($comment_flag, $xpath_expression [, $xpath_context ], $inclusive_prefix_list);
$str = $doc->serialize($format);
$state = $doc->toFile($filename, $format);
$state = $doc->toFH($fh, $format);
$str = $document->toStringHTML();
$str = $document->serialize_html();
$bool = $dom->is_valid();
$dom->validate();
$root = $dom->documentElement();
$dom->setDocumentElement( $root );
$element = $dom->createElement( $nodename );
$element = $dom->createElementNS( $namespaceURI, $nodename );
$text = $dom->createTextNode( $content_text );
$comment = $dom->createComment( $comment_text );
$attrnode = $doc->createAttribute($name [,$value]);
$attrnode = $doc->createAttributeNS( namespaceURI, $name [,$value] );
$fragment = $doc->createDocumentFragment();
$cdata = $dom->createCDATASection( $cdata_content );
my $pi = $doc->createProcessingInstruction( $target, $data );
my $entref = $doc->createEntityReference($refname);
$dtd = $document->createInternalSubset( $rootnode, $public, $system);
$dtd = $document->createExternalSubset( $rootnode_name, $publicId, $systemId);
$document->importNode( $node );
$document->adoptNode( $node );
my $dtd = $doc->externalSubset;
my $dtd = $doc->internalSubset;
$doc->setExternalSubset($dtd);
$doc->setInternalSubset($dtd);
my $dtd = $doc->removeExternalSubset();
my $dtd = $doc->removeInternalSubset();
my @nodelist = $doc->getElementsByTagName($tagname);
my @nodelist = $doc->getElementsByTagNameNS($nsURI,$tagname);
my @nodelist = $doc->getElementsByLocalName($localname);
my $node = $doc->getElementById($id);
$dom->indexElements();
=head1 DESCRIPTION
The Document Class is in most cases the result of a parsing process. But
sometimes it is necessary to create a Document from scratch. The DOM Document
Class provides functions that conform to the DOM Core naming style.
It inherits all functions from L<<<<<< XML::LibXML::Node >>>>>> as specified in the DOM specification. This enables access to the nodes besides
the root element on document level - a C<<<<<< DTD >>>>>> for example. The support for these nodes is limited at the moment.
While generally nodes are bound to a document in the DOM concept it is
suggested that one should always create a node not bound to any document. There
is no need of really including the node to the document, but once the node is
bound to a document, it is quite safe that all strings have the correct
encoding. If an unbound text node with an ISO encoded string is created (e.g.
with $CLASS->new()), the C<<<<<< toString >>>>>> function may not return the expected result.
To prevent such problems, it is recommended to pass all data to XML::LibXML
methods as character strings (i.e. UTF-8 encoded, with the UTF8 flag on).
=head1 METHODS
Many functions listed here are extensively documented in the DOM Level 3 specification (L<<<<<< http://www.w3.org/TR/DOM-Level-3-Core/ >>>>>>). Please refer to the specification for extensive documentation.
=over 4
=item new
$dom = XML::LibXML::Document->new( $version, $encoding );
alias for createDocument()
=item createDocument
$dom = XML::LibXML::Document->createDocument( $version, $encoding );
The constructor for the document class. As Parameter it takes the version
string and (optionally) the encoding string. Simply calling I<<<<<< createDocument >>>>>>() will create the document:
Both parameter are optional. The default value for I<<<<<< $version >>>>>> is C<<<<<< 1.0 >>>>>>, of course. If the I<<<<<< $encoding >>>>>> parameter is not set, the encoding will be left unset, which means UTF-8 is
implied.
The call of I<<<<<< createDocument >>>>>>() without any parameter will result the following code:
Alternatively one can call this constructor directly from the XML::LibXML class
level, to avoid some typing. This will not have any effect on the class
instance, which is always XML::LibXML::Document.
my $document = XML::LibXML->createDocument( "1.0", "UTF-8" );
is therefore a shortcut for
my $document = XML::LibXML::Document->createDocument( "1.0", "UTF-8" );
=item URI
$strURI = $doc->URI();
Returns the URI (or filename) of the original document. For documents obtained
by parsing a string of a FH without using the URI parsing argument of the
corresponding C<<<<<< parse_* >>>>>> function, the result is a generated string unknown-XYZ where XYZ is some
number; for documents created with the constructor C<<<<<< new >>>>>>, the URI is undefined.
The value can be modified by calling C<<<<<< setURI >>>>>> method on the document node.
=item setURI
$doc->setURI($strURI);
Sets the URI of the document reported by the method URI (see also the URI
argument to the various C<<<<<< parse_* >>>>>> functions).
=item encoding
$strEncoding = $doc->encoding();
returns the encoding string of the document.
my $doc = XML::LibXML->createDocument( "1.0", "ISO-8859-15" );
print $doc->encoding; # prints ISO-8859-15
=item actualEncoding
$strEncoding = $doc->actualEncoding();
returns the encoding in which the XML will be returned by $doc->toString().
This is usually the original encoding of the document as declared in the XML
declaration and returned by $doc->encoding. If the original encoding is not
known (e.g. if created in memory or parsed from a XML without a declared
encoding), 'UTF-8' is returned.
my $doc = XML::LibXML->createDocument( "1.0", "ISO-8859-15" );
print $doc->encoding; # prints ISO-8859-15
=item setEncoding
$doc->setEncoding($new_encoding);
This method allows one to change the declaration of encoding in the XML
declaration of the document. The value also affects the encoding in which the
document is serialized to XML by $doc->toString(). Use setEncoding() to remove
the encoding declaration.
=item version
$strVersion = $doc->version();
returns the version string of the document
I<<<<<< getVersion() >>>>>> is an alternative form of this function.
=item standalone
$doc->standalone
This function returns the Numerical value of a documents XML declarations
standalone attribute. It returns I<<<<<< 1 >>>>>> if standalone="yes" was found, I<<<<<< 0 >>>>>> if standalone="no" was found and I<<<<<< -1 >>>>>> if standalone was not specified (default on creation).
=item setStandalone
$doc->setStandalone($numvalue);
Through this method it is possible to alter the value of a documents standalone
attribute. Set it to I<<<<<< 1 >>>>>> to set standalone="yes", to I<<<<<< 0 >>>>>> to set standalone="no" or set it to I<<<<<< -1 >>>>>> to remove the standalone attribute from the XML declaration.
=item compression
my $compression = $doc->compression;
libxml2 allows reading of documents directly from gzipped files. In this case
the compression variable is set to the compression level of that file (0-8). If
XML::LibXML parsed a different source or the file wasn't compressed, the
returned value will be I<<<<<< -1 >>>>>>.
=item setCompression
$doc->setCompression($ziplevel);
If one intends to write the document directly to a file, it is possible to set
the compression level for a given document. This level can be in the range from
0 to 8. If XML::LibXML should not try to compress use I<<<<<< -1 >>>>>> (default).
Note that this feature will I<<<<<< only >>>>>> work if libxml2 is compiled with zlib support and toFile() is used for output.
=item toString
$docstring = $dom->toString($format);
I<<<<<< toString >>>>>> is a DOM serializing function, so the DOM Tree is serialized into an XML
string, ready for output.
IMPORTANT: unlike toString for other nodes, on document nodes this function
returns the XML as a byte string in the original encoding of the document (see
the actualEncoding() method)! This means you can simply do:
open my $out_fh, '>', $file;
print {$out_fh} $doc->toString;
regardless of the actual encoding of the document. See the section on encodings
in L<<<<<< XML::LibXML >>>>>> for more details.
The optional I<<<<<< $format >>>>>> parameter sets the indenting of the output. This parameter is expected to be an C<<<<<< integer >>>>>> value, that specifies that indentation should be used. The format parameter can
have three different values if it is used:
If $format is 0, than the document is dumped as it was originally parsed
If $format is 1, libxml2 will add ignorable white spaces, so the nodes content
is easier to read. Existing text nodes will not be altered
If $format is 2 (or higher), libxml2 will act as $format == 1 but it add a
leading and a trailing line break to each text node.
libxml2 uses a hard-coded indentation of 2 space characters per indentation
level. This value can not be altered on run-time.
=item toStringC14N
$c14nstr = $doc->toStringC14N($comment_flag, $xpath_expression [, $xpath_context ]);
See the documentation in L<<<<<< XML::LibXML::Node >>>>>>.
=item toStringEC14N
$ec14nstr = $doc->toStringEC14N($comment_flag, $xpath_expression [, $xpath_context ], $inclusive_prefix_list);
See the documentation in L<<<<<< XML::LibXML::Node >>>>>>.
=item serialize
$str = $doc->serialize($format);
An alias for toString(). This function was name added to be more consistent
with libxml2.
=item serialize_c14n
An alias for toStringC14N().
=item serialize_exc_c14n
An alias for toStringEC14N().
=item toFile
$state = $doc->toFile($filename, $format);
This function is similar to toString(), but it writes the document directly
into a filesystem. This function is very useful, if one needs to store large
documents.
The format parameter has the same behaviour as in toString().
=item toFH
$state = $doc->toFH($fh, $format);
This function is similar to toString(), but it writes the document directly to
a filehandle or a stream. A byte stream in the document encoding is passed to
the file handle. Do NOT apply any C<<<<<< :encoding(...) >>>>>> or C<<<<<< :utf8 >>>>>> PerlIO layer to the filehandle! See the section on encodings in L<<<<<< XML::LibXML >>>>>> for more details.
The format parameter has the same behaviour as in toString().
=item toStringHTML
$str = $document->toStringHTML();
I<<<<<< toStringHTML >>>>>> serialize the tree to a byte string in the document encoding as HTML. With this
method indenting is automatic and managed by libxml2 internally. Note the
string must contain (rather than the newer ), else all
non-ASCII will become entities.
=item serialize_html
$str = $document->serialize_html();
An alias for toStringHTML().
=item is_valid
$bool = $dom->is_valid();
Returns either TRUE or FALSE depending on whether the DOM Tree is a valid
Document or not.
You may also pass in a L<<<<<< XML::LibXML::Dtd >>>>>> object, to validate against an external DTD:
if (!$dom->is_valid($dtd)) {
warn("document is not valid!");
}
=item validate
$dom->validate();
This is an exception throwing equivalent of is_valid. If the document is not
valid it will throw an exception containing the error. This allows you much
better error reporting than simply is_valid or not.
Again, you may pass in a DTD object
=item documentElement
$root = $dom->documentElement();
Returns the root element of the Document. A document can have just one root
element to contain the documents data.
Optionally one can use I<<<<<< getDocumentElement >>>>>>.
=item setDocumentElement
$dom->setDocumentElement( $root );
This function enables you to set the root element for a document. The function
supports the import of a node from a different document tree, but does not
support a document fragment as $root.
=item createElement
$element = $dom->createElement( $nodename );
This function creates a new Element Node bound to the DOM with the name C<<<<<< $nodename >>>>>>.
=item createElementNS
$element = $dom->createElementNS( $namespaceURI, $nodename );
This function creates a new Element Node bound to the DOM with the name C<<<<<< $nodename >>>>>> and placed in the given namespace.
=item createTextNode
$text = $dom->createTextNode( $content_text );
As an equivalent of I<<<<<< createElement >>>>>>, but it creates a I<<<<<< Text Node >>>>>> bound to the DOM.
=item createComment
$comment = $dom->createComment( $comment_text );
As an equivalent of I<<<<<< createElement >>>>>>, but it creates a I<<<<<< Comment Node >>>>>> bound to the DOM.
=item createAttribute
$attrnode = $doc->createAttribute($name [,$value]);
Creates a new Attribute node.
=item createAttributeNS
$attrnode = $doc->createAttributeNS( namespaceURI, $name [,$value] );
Creates an Attribute bound to a namespace.
=item createDocumentFragment
$fragment = $doc->createDocumentFragment();
This function creates a DocumentFragment.
=item createCDATASection
$cdata = $dom->createCDATASection( $cdata_content );
Similar to createTextNode and createComment, this function creates a
CDataSection bound to the current DOM.
=item createProcessingInstruction
my $pi = $doc->createProcessingInstruction( $target, $data );
create a processing instruction node.
Since this method is quite long one may use its short form I<<<<<< createPI() >>>>>>.
=item createEntityReference
my $entref = $doc->createEntityReference($refname);
If a document has a DTD specified, one can create entity references by using
this function. If one wants to add a entity reference to the document, this
reference has to be created by this function.
An entity reference is unique to a document and cannot be passed to other
documents as other nodes can be passed.
I<<<<<< NOTE: >>>>>> A text content containing something that looks like an entity reference, will
not be expanded to a real entity reference unless it is a predefined entity
my $string = "&foo;";
$some_element->appendText( $string );
print $some_element->textContent; # prints "&foo;"
=item createInternalSubset
$dtd = $document->createInternalSubset( $rootnode, $public, $system);
This function creates and adds an internal subset to the given document.
Because the function automatically adds the DTD to the document there is no
need to add the created node explicitly to the document.
my $document = XML::LibXML::Document->new();
my $dtd = $document->createInternalSubset( "foo", undef, "foo.dtd" );
will result in the following XML document:
By setting the public parameter it is possible to set PUBLIC DTDs to a given
document. So
my $document = XML::LibXML::Document->new();
my $dtd = $document->createInternalSubset( "foo", "-//FOO//DTD FOO 0.1//EN", undef );
will cause the following declaration to be created on the document:
=item createExternalSubset
$dtd = $document->createExternalSubset( $rootnode_name, $publicId, $systemId);
This function is similar to C<<<<<< createInternalSubset() >>>>>> but this DTD is considered to be external and is therefore not added to the
document itself. Nevertheless it can be used for validation purposes.
=item importNode
$document->importNode( $node );
If a node is not part of a document, it can be imported to another document. As
specified in DOM Level 2 Specification the Node will not be altered or removed
from its original document (C<<<<<< $node-EcloneNode(1) >>>>>> will get called implicitly).
I<<<<<< NOTE: >>>>>> Don't try to use importNode() to import sub-trees that contain an entity
reference - even if the entity reference is the root node of the sub-tree. This
will cause serious problems to your program. This is a limitation of libxml2
and not of XML::LibXML itself.
=item adoptNode
$document->adoptNode( $node );
If a node is not part of a document, it can be imported to another document. As
specified in DOM Level 3 Specification the Node will not be altered but it will
removed from its original document.
After a document adopted a node, the node, its attributes and all its
descendants belong to the new document. Because the node does not belong to the
old document, it will be unlinked from its old location first.
I<<<<<< NOTE: >>>>>> Don't try to adoptNode() to import sub-trees that contain entity references -
even if the entity reference is the root node of the sub-tree. This will cause
serious problems to your program. This is a limitation of libxml2 and not of
XML::LibXML itself.
=item externalSubset
my $dtd = $doc->externalSubset;
If a document has an external subset defined it will be returned by this
function.
I<<<<<< NOTE >>>>>> Dtd nodes are no ordinary nodes in libxml2. The support for these nodes in
XML::LibXML is still limited. In particular one may not want use common node
function on doctype declaration nodes!
=item internalSubset
my $dtd = $doc->internalSubset;
If a document has an internal subset defined it will be returned by this
function.
I<<<<<< NOTE >>>>>> Dtd nodes are no ordinary nodes in libxml2. The support for these nodes in
XML::LibXML is still limited. In particular one may not want use common node
function on doctype declaration nodes!
=item setExternalSubset
$doc->setExternalSubset($dtd);
I<<<<<< EXPERIMENTAL! >>>>>>
This method sets a DTD node as an external subset of the given document.
=item setInternalSubset
$doc->setInternalSubset($dtd);
I<<<<<< EXPERIMENTAL! >>>>>>
This method sets a DTD node as an internal subset of the given document.
=item removeExternalSubset
my $dtd = $doc->removeExternalSubset();
I<<<<<< EXPERIMENTAL! >>>>>>
If a document has an external subset defined it can be removed from the
document by using this function. The removed dtd node will be returned.
=item removeInternalSubset
my $dtd = $doc->removeInternalSubset();
I<<<<<< EXPERIMENTAL! >>>>>>
If a document has an internal subset defined it can be removed from the
document by using this function. The removed dtd node will be returned.
=item getElementsByTagName
my @nodelist = $doc->getElementsByTagName($tagname);
Implements the DOM Level 2 function
In SCALAR context this function returns an L<<<<<< XML::LibXML::NodeList >>>>>> object.
=item getElementsByTagNameNS
my @nodelist = $doc->getElementsByTagNameNS($nsURI,$tagname);
Implements the DOM Level 2 function
In SCALAR context this function returns an L<<<<<< XML::LibXML::NodeList >>>>>> object.
=item getElementsByLocalName
my @nodelist = $doc->getElementsByLocalName($localname);
This allows the fetching of all nodes from a given document with the given
Localname.
In SCALAR context this function returns an L<<<<<< XML::LibXML::NodeList >>>>>> object.
=item getElementById
my $node = $doc->getElementById($id);
Returns the element that has an ID attribute with the given value. If no such
element exists, this returns undef.
Note: the ID of an element may change while manipulating the document. For
documents with a DTD, the information about ID attributes is only available if
DTD loading/validation has been requested. For HTML documents parsed with the
HTML parser ID detection is done automatically. In XML documents, all "xml:id"
attributes are considered to be of type ID. You can test ID-ness of an
attribute node with $attr->isId().
In versions 1.59 and earlier this method was called getElementsById() (plural)
by mistake. Starting from 1.60 this name is maintained as an alias only for
backward compatibility.
=item indexElements
$dom->indexElements();
This function causes libxml2 to stamp all elements in a document with their
document position index which considerably speeds up XPath queries for large
documents. It should only be used with static documents that won't be further
changed by any DOM methods, because once a document is indexed, XPath will
always prefer the index to other methods of determining the document order of
nodes. XPath could therefore return improperly ordered node-lists when applied
on a document that has been changed after being indexed. It is of course
possible to use this method to re-index a modified document before using it
with XPath again. This function is not a part of the DOM specification.
This function returns number of elements indexed, -1 if error occurred, or -2
if this feature is not available in the running libxml2.
=back
=head1 AUTHORS
Matt Sergeant,
Christian Glahn,
Petr Pajas
=head1 VERSION
2.0213
=head1 COPYRIGHT
2001-2007, AxKit.com Ltd.
2002-2006, Christian Glahn.
2006-2009, Petr Pajas.
=cut
=head1 LICENSE
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
NodeList.pm 0000444 00000016456 15234477232 0006646 0 ustar 00 # $Id$
#
# This is free software, you may use it and distribute it under the same terms as
# Perl itself.
#
# Copyright 2001-2003 AxKit.com Ltd., 2002-2006 Christian Glahn, 2006-2009 Petr Pajas
#
#
package XML::LibXML::NodeList;
use strict;
use warnings;
use XML::LibXML::Boolean;
use XML::LibXML::Literal;
use XML::LibXML::Number;
our $VERSION = "2.0213"; # VERSION TEMPLATE: DO NOT CHANGE
use overload
'""' => \&to_literal,
'bool' => \&to_boolean,
'cmp' => sub {
my($aa, $bb, $order) = @_;
return ($order ? ("$bb" cmp "$aa") : ("$aa" cmp "$bb"));
},
;
sub new {
my $class = shift;
bless [@_], $class;
}
sub new_from_ref {
my ($class,$array_ref,$reuse) = @_;
return bless $reuse ? $array_ref : [@$array_ref], $class;
}
sub pop {
my $self = CORE::shift;
CORE::pop @$self;
}
sub push {
my $self = CORE::shift;
CORE::push @$self, @_;
}
sub append {
my $self = CORE::shift;
my ($nodelist) = @_;
CORE::push @$self, $nodelist->get_nodelist;
}
sub shift {
my $self = CORE::shift;
CORE::shift @$self;
}
sub unshift {
my $self = CORE::shift;
CORE::unshift @$self, @_;
}
sub prepend {
my $self = CORE::shift;
my ($nodelist) = @_;
CORE::unshift @$self, $nodelist->get_nodelist;
}
sub size {
my $self = CORE::shift;
scalar @$self;
}
sub get_node {
# uses array index starting at 1, not 0
# this is mainly because of XPath.
my $self = CORE::shift;
my ($pos) = @_;
$self->[$pos - 1];
}
sub item
{
my ($self, $pos) = @_;
return $self->[$pos];
}
sub get_nodelist {
my $self = CORE::shift;
@$self;
}
sub to_boolean {
my $self = CORE::shift;
return (@$self > 0) ? XML::LibXML::Boolean->True : XML::LibXML::Boolean->False;
}
# string-value of a nodelist is the string-value of the first node
sub string_value {
my $self = CORE::shift;
return '' unless @$self;
return $self->[0]->string_value;
}
sub to_literal {
my $self = CORE::shift;
return XML::LibXML::Literal->new(
join('', CORE::grep {defined $_} CORE::map { $_->string_value } @$self)
);
}
sub to_literal_delimited {
my $self = CORE::shift;
return XML::LibXML::Literal->new(
join(CORE::shift, CORE::grep {defined $_} CORE::map { $_->string_value } @$self)
);
}
sub to_literal_list {
my $self = CORE::shift;
my @nodes = CORE::map{ XML::LibXML::Literal->new($_->string_value())->value() } @{$self};
if (wantarray) {
return( @nodes );
}
return( \@nodes );
}
sub to_number {
my $self = CORE::shift;
return XML::LibXML::Number->new(
$self->to_literal
);
}
sub iterator {
warn "this function is obsolete!\nIt was disabled in version 1.54\n";
return undef;
}
sub map {
my $self = CORE::shift;
my $sub = __is_code(CORE::shift);
local $_;
my @results = CORE::map { @{[ $sub->($_) ]} } @$self;
return unless defined wantarray;
return wantarray ? @results : (ref $self)->new(@results);
}
sub grep {
my $self = CORE::shift;
my $sub = __is_code(CORE::shift);
local $_;
my @results = CORE::grep { $sub->($_) } @$self;
return unless defined wantarray;
return wantarray ? @results : (ref $self)->new(@results);
}
sub sort {
my $self = CORE::shift;
my $sub = __is_code(CORE::shift);
my @results = CORE::sort { $sub->($a,$b) } @$self;
return wantarray ? @results : (ref $self)->new(@results);
}
sub foreach {
my $self = CORE::shift;
my $sub = CORE::shift;
foreach my $item (@$self)
{
local $_ = $item;
$sub->($item);
}
return wantarray ? @$self : $self;
}
sub reverse {
my $self = CORE::shift;
my @results = CORE::reverse @$self;
return wantarray ? @results : (ref $self)->new(@results);
}
sub reduce {
my $self = CORE::shift;
my $sub = __is_code(CORE::shift);
my @list = @$self;
CORE::unshift @list, $_[0] if @_;
my $a = CORE::shift(@list);
foreach my $b (@list)
{
$a = $sub->($a, $b);
}
return $a;
}
sub __is_code {
my ($code) = @_;
if (ref $code eq 'CODE') {
return $code;
}
# There are better ways of doing this, but here I've tried to
# avoid adding any additional external dependencies.
#
if (UNIVERSAL::can($code, 'can') # is blessed (sort of)
and overload::Overloaded($code) # is overloaded
and overload::Method($code, '&{}')) { # overloads '&{}'
return $code;
}
# The other possibility is that $code is a coderef, but is
# blessed into a class that doesn't overload '&{}'. In which
# case... well, I'm stumped!
die "Not a subroutine reference\n";
}
1;
__END__
=head1 NAME
XML::LibXML::NodeList - a list of XML document nodes
=head1 DESCRIPTION
An XML::LibXML::NodeList object contains an ordered list of nodes, as
detailed by the W3C DOM documentation of Node Lists.
=head1 SYNOPSIS
my $results = $dom->findnodes('//somepath');
foreach my $context ($results->get_nodelist) {
my $newresults = $context->findnodes('./other/element');
...
}
=head1 API
=head2 new(@nodes)
You will almost never have to create a new NodeList object, as it is all
done for you by XPath.
=head2 get_nodelist()
Returns a list of nodes, the contents of the node list, as a perl list.
=head2 string_value()
Returns the string-value of the first node in the list.
See the XPath specification for what "string-value" means.
=head2 to_literal()
Returns the concatenation of all the string-values of all
the nodes in the list.
=head2 to_literal_delimited($separator)
Returns the concatenation of all the string-values of all
the nodes in the list, delimited by the specified separator.
=head2 to_literal_list()
Returns all the string-values of all the nodes in the list as
a perl list.
=head2 get_node($pos)
Returns the node at $pos. The node position in XPath is based at 1, not 0.
=head2 size()
Returns the number of nodes in the NodeList.
=head2 pop()
Equivalent to perl's pop function.
=head2 push(@nodes)
Equivalent to perl's push function.
=head2 append($nodelist)
Given a nodelist, appends the list of nodes in $nodelist to the end of the
current list.
=head2 shift()
Equivalent to perl's shift function.
=head2 unshift(@nodes)
Equivalent to perl's unshift function.
=head2 prepend($nodelist)
Given a nodelist, prepends the list of nodes in $nodelist to the front of
the current list.
=head2 map($coderef)
Equivalent to perl's map function.
=head2 grep($coderef)
Equivalent to perl's grep function.
=head2 sort($coderef)
Equivalent to perl's sort function.
Caveat: Perl's magic C<$a> and C<$b> variables are not available in
C<$coderef>. Instead the two terms are passed to the coderef as arguments.
=head2 reverse()
Equivalent to perl's reverse function.
=head2 foreach($coderef)
Inspired by perl's foreach loop. Executes the coderef on each item in
the list. Similar to C