XML::LibXML::Document • man page

XML::LibXML::Document (3)

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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 (<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

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

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 "&amp;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

SCALAR

context this function returns an XML::LibXML::NodeList object.

getElementsByTagNameNS

  my @nodelist = $doc->getElementsByTagNameNS($nsURI,$tagname);

Implements the

DOM

Level 2 function

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.

SCALAR

context this function returns an XML::LibXML::NodeList object.

getElementById

  my $node = $doc->getElementById($id);

Returns the element that has an

attribute with the given value. If no such element exists, this returns undef.

Note: the

of an element may change while manipulating the document. For documents with a

DTD,

the information about

attributes is only available if

DTD

loading/validation has been requested. For

HTML

documents parsed with the

HTML

parser

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

2.0122

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.

XML::LibXML::Document • man page

XML::LibXML::Document • man page

XML::LibXML::Document (3)

Leading comments

NAME

SYNOPSIS

DESCRIPTION

METHODS

AUTHORS

VERSION

COPYRIGHT

LICENSE

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