NAME¶
XML::LibXML::Document - XML::LibXML DOM Document Class
SYNOPSIS¶
use XML::LibXML;
# Only methods specific to Document nodes are listed here,
# see 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 [, $xpath_context ]);
$ec14nstr = $doc->toStringEC14N($comment_flag, $xpath [, $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, $qname );
$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();
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 XML::LibXML::Node as specified in the DOM
specification. This enables access to the nodes besides the root element on
document level - a "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 "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).
METHODS¶
Many functions listed here are extensively documented in the DOM Level 3
specification (<
http://www.w3.org/TR/DOM-Level-3-Core/>). Please refer
to the specification for extensive documentation.
- new
-
$dom = XML::LibXML::Document->new( $version, $encoding );
alias for createDocument()
- 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
createDocument() will create the document:
<?xml version="your version" encoding="your encoding"?>
Both parameter are optional. The default value for
$version is 1.0, of course. If the
$encoding parameter is not set, the encoding will be
left unset, which means UTF-8 is implied.
The call of createDocument() without any parameter will result the
following code:
<?xml version="1.0"?>
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" );
- 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 "parse_*" function, the result is
a generated string unknown-XYZ where XYZ is some number; for documents
created with the constructor "new", the URI is undefined.
The value can be modified by calling "setURI" method on the
document node.
- setURI
-
$doc->setURI($strURI);
Sets the URI of the document reported by the method URI (see also the URI
argument to the various "parse_*" functions).
- 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
- 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
- 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.
- version
-
$strVersion = $doc->version();
returns the version string of the document
getVersion() is an alternative form of this
function.
- standalone
-
$doc->standalone
This function returns the Numerical value of a documents XML declarations
standalone attribute. It returns 1 if standalone="yes"
was found, 0 if standalone="no" was found and -1
if standalone was not specified (default on creation).
- setStandalone
-
$doc->setStandalone($numvalue);
Through this method it is possible to alter the value of a documents
standalone attribute. Set it to 1 to set
standalone="yes", to 0 to set standalone="no"
or set it to -1 to remove the standalone attribute from the XML
declaration.
- 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 -1.
- 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 -1
(default).
Note that this feature will only work if libxml2 is compiled with
zlib support and toFile() is used for output.
- toString
-
$docstring = $dom->toString($format);
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 XML::LibXML for more details.
The optional $format parameter sets the indenting of
the output. This parameter is expected to be an "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.
- toStringC14N
-
$c14nstr = $doc->toStringC14N($comment_flag, $xpath [, $xpath_context ]);
See the documentation in XML::LibXML::Node.
- toStringEC14N
-
$ec14nstr = $doc->toStringEC14N($comment_flag, $xpath [, $xpath_context ], $inclusive_prefix_list);
See the documentation in XML::LibXML::Node.
- serialize
-
$str = $doc->serialize($format);
An alias for toString(). This function was name added to be more
consistent with libxml2.
- serialize_c14n
- An alias for toStringC14N().
- serialize_exc_c14n
- An alias for toStringEC14N().
- 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().
- 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
":encoding(...)" or ":utf8" PerlIO layer to the
filehandle! See the section on encodings in XML::LibXML for more details.
The format parameter has the same behaviour as in toString().
- toStringHTML
-
$str = $document->toStringHTML();
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.
- serialize_html
-
$str = $document->serialize_html();
An alias for toStringHTML().
- is_valid
-
$bool = $dom->is_valid();
Returns either TRUE or FALSE depending on whether the DOM Tree is a valid
Document or not.
You may also pass in a XML::LibXML::Dtd object, to validate against an
external DTD:
if (!$dom->is_valid($dtd)) {
warn("document is not valid!");
}
- 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
- 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 getDocumentElement.
- 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.
- createElement
-
$element = $dom->createElement( $nodename );
This function creates a new Element Node bound to the DOM with the name
$nodename.
- createElementNS
-
$element = $dom->createElementNS( $namespaceURI, $qname );
This function creates a new Element Node bound to the DOM with the name
$nodename and placed in the given namespace.
- createTextNode
-
$text = $dom->createTextNode( $content_text );
As an equivalent of createElement, but it creates a Text Node
bound to the DOM.
- createComment
-
$comment = $dom->createComment( $comment_text );
As an equivalent of createElement, but it creates a Comment
Node bound to the DOM.
- createAttribute
-
$attrnode = $doc->createAttribute($name [,$value]);
Creates a new Attribute node.
- createAttributeNS
-
$attrnode = $doc->createAttributeNS( namespaceURI, $name [,$value] );
Creates an Attribute bound to a namespace.
- createDocumentFragment
-
$fragment = $doc->createDocumentFragment();
This function creates a DocumentFragment.
- createCDATASection
-
$cdata = $dom->createCDATASection( $cdata_content );
Similar to createTextNode and createComment, this function creates a
CDataSection bound to the current DOM.
- createProcessingInstruction
-
my $pi = $doc->createProcessingInstruction( $target, $data );
create a processing instruction node.
Since this method is quite long one may use its short form
createPI() .
- 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.
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;"
- 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:
<?xml version="1.0"?>
<!DOCTYPE foo SYSTEM "foo.dtd">
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:
<?xml version="1.0"?>
<!DOCTYPE foo PUBLIC "-//FOO//DTD FOO 0.1//EN">
- createExternalSubset
-
$dtd = $document->createExternalSubset( $rootnode_name, $publicId, $systemId);
This function is similar to "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.
- importNode
-
$document->importNode( $node );
If a node is not part of a document, it can be imported to another document.
As specified in DOM Level 2 Specification the Node will not be altered or
removed from its original document ("$node->cloneNode(1)"
will get called implicitly).
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.
- 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.
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.
- externalSubset
-
my $dtd = $doc->externalSubset;
If a document has an external subset defined it will be returned by this
function.
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!
- internalSubset
-
my $dtd = $doc->internalSubset;
If a document has an internal subset defined it will be returned by this
function.
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!
- setExternalSubset
-
$doc->setExternalSubset($dtd);
EXPERIMENTAL!
This method sets a DTD node as an external subset of the given
document.
- setInternalSubset
-
$doc->setInternalSubset($dtd);
EXPERIMENTAL!
This method sets a DTD node as an internal subset of the given
document.
- removeExternalSubset
-
my $dtd = $doc->removeExternalSubset();
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.
- removeInternalSubset
-
my $dtd = $doc->removeInternalSubset();
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.
- getElementsByTagName
-
my @nodelist = $doc->getElementsByTagName($tagname);
Implements the DOM Level 2 function
In SCALAR context this function returns an XML::LibXML::NodeList
object.
- getElementsByTagNameNS
-
my @nodelist = $doc->getElementsByTagNameNS($nsURI,$tagname);
Implements the DOM Level 2 function
In SCALAR context this function returns an XML::LibXML::NodeList
object.
- 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 XML::LibXML::NodeList
object.
- 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.
- 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.
AUTHORS¶
Matt Sergeant, Christian Glahn, Petr Pajas
VERSION¶
2.0116
COPYRIGHT¶
2001-2007, AxKit.com Ltd.
2002-2006, Christian Glahn.
2006-2009, Petr Pajas.
LICENSE¶
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.