XML::LibXML::Document(User Contributed Perl DocumentXML::LibXML::Document(3pm)
NAME
XML::LibXML::Document - XML::LibXML DOM Document Class
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 [, $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, $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();
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, $nodename );
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
2.0134
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.
perl v5.36.0 2022-10-19 XML::LibXML::Document(3pm)
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