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# XXXI. DOM XML Functions

# Introduction

The DOM XML extension has been overhauled in PHP 4.3.0 to better comply with the DOM standard. The extension still contains many old functions, but they should no longer be used. In particular, functions that are not object-oriented should be avoided.

The extension allows you to operate on an XML document with the DOM API. It also provides a function domxml_xmltree() to turn the complete XML document into a tree of PHP objects. Currently, this tree should be considered read-only - you can modify it, but this would not make any sense since DomDocument_dump_mem() cannot be applied to it. Therefore, if you want to read an XML file and write a modified version, use DomDocument_create_element(), DomDocument_create_text_node(), set_attribute(), etc. and finally the DomDocument_dump_mem() function.

> Note: This extension has been moved to the PECL repository and is no longer bundled with PHP as of PHP 5.0.0.

> Note: This extension is no longer marked experimental. It will, however, never be released with PHP 5, and will only be distributed with PHP 4. If you need DOM XML support with PHP 5 you can use the DOM extension. This domxml extension is not compatible with the DOM extension.

# Requirements

This extension makes use of the GNOME XML library. Download and install this library. You will need at least libxml-2.4.14. To use DOM XSLT features you can use the libxslt library and EXSLT enhancements from http://www.exslt.org/. Download and install these libraries if you plan to use (enhanced) XSLT features. You will need at least libxslt-1.0.18.

# Installation

This PECL extension is not bundled with PHP. Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: http://pecl.php.net/package/domxml.

In PHP 4 this PECL extensions source can be found in the `ext/` directory within the PHP source or at the PECL link above. This extension is only available if PHP was configured with --with-dom[=DIR]. Add --with-dom-xslt[=DIR] to include DOM XSLT support. DIR is the libxslt install directory. Add --with-dom-exslt[=DIR] to include DOM EXSLT support, where DIR is the libexslt install directory.

Windows users will enable `php_domxml.dll` inside of `php.ini` in order to use these functions. In PHP 4 this DLL resides in the `extensions/` directory within the PHP Windows binaries download. You may download this PECL extension DLL from the PHP Downloads page or at http://snaps.php.net/. Also, there is one additional DLL that must be made available to your system's PATH in order for this extension to work. In PHP 4 this is in the `dlls/` directory. It's name: For PHP <= 4.2.0, it's `libxml2.dll`. For PHP >= 4.3.0, it's `iconv.dll`. And as of PHP 5.0.0, iconv is compiled into your Windows PHP binaries by default so no extra DLL is needed.

# Deprecated functions

There are quite a few functions that do not fit into the DOM standard and should no longer be used. These functions are listed in the following table. The function DomNode_append_child() has changed its behaviour. It now adds a child and not a sibling. If this breaks your application, use the non-DOM function DomNode_append_sibling().

Table 1. Deprecated functions and their replacements

Old function | New function
--- | ---
xmldoc | domxml_open_mem()
xmldocfile | domxml_open_file()
domxml_new_xmldoc | domxml_new_doc()
domxml_dump_mem | DomDocument_dump_mem()
domxml_dump_mem_file | DomDocument_dump_file()
DomDocument_dump_mem_file | DomDocument_dump_file()
DomDocument_add_root | DomDocument_create_element() followed by DomNode_append_child()
DomDocument_dtd | DomDocument_doctype()
DomDocument_root | DomDocument_document_element()
DomDocument_children | DomNode_child_nodes()
DomDocument_imported_node | No replacement.
DomNode_add_child | Create a new node with e.g. DomDocument_create_element() and add it with DomNode_append_child().
DomNode_children | DomNode_child_nodes()
DomNode_parent | DomNode_parent_node()
DomNode_new_child | Create a new node with e.g. DomDocument_create_element() and add it with DomNode_append_child().
DomNode_set_content | Create a new node with e.g. DomDocument_create_text_node() and add it with DomNode_append_child().
DomNode_get_content | Content is just a text node and can be accessed with DomNode_child_nodes().
DomNode_set_content | Content is just a text node and can be added with DomNode_append_child().

# Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

Table 2. XML constants

Constant | Value | Description
--- | --- | ---
`XML_ELEMENT_NODE` (integer) | 1 | Node is an element
`XML_ATTRIBUTE_NODE` (integer) | 2 | Node is an attribute
`XML_TEXT_NODE` (integer) | 3 | Node is a piece of text
`XML_CDATA_SECTION_NODE` (integer) | 4 |
`XML_ENTITY_REF_NODE` (integer) | 5 |
`XML_ENTITY_NODE` (integer) | 6 | Node is an entity like &nbsp;
`XML_PI_NODE` (integer) | 7 | Node is a processing instruction
`XML_COMMENT_NODE` (integer) | 8 | Node is a comment
`XML_DOCUMENT_NODE` (integer) | 9 | Node is a document
`XML_DOCUMENT_TYPE_NODE` (integer) | 10 |
`XML_DOCUMENT_FRAG_NODE` (integer) | 11 |
`XML_NOTATION_NODE` (integer) | 12 |
`XML_GLOBAL_NAMESPACE` (integer) | 1 |
`XML_LOCAL_NAMESPACE` (integer) | 2 |
`XML_HTML_DOCUMENT_NODE` (integer) |  |
`XML_DTD_NODE` (integer) |  |
`XML_ELEMENT_DECL_NODE` (integer) |  |
`XML_ATTRIBUTE_DECL_NODE` (integer) |  |
`XML_ENTITY_DECL_NODE` (integer) |  |
`XML_NAMESPACE_DECL_NODE` (integer) |  |
`XML_ATTRIBUTE_CDATA` (integer) |  |
`XML_ATTRIBUTE_ID` (integer) |  |
`XML_ATTRIBUTE_IDREF` (integer) |  |
`XML_ATTRIBUTE_IDREFS` (integer) |  |
`XML_ATTRIBUTE_ENTITY` (integer) |  |
`XML_ATTRIBUTE_NMTOKEN` (integer) |  |
`XML_ATTRIBUTE_NMTOKENS` (integer) |  |
`XML_ATTRIBUTE_ENUMERATION` (integer) |  |
`XML_ATTRIBUTE_NOTATION` (integer) |  |
`XPATH_UNDEFINED` (integer) |  |
`XPATH_NODESET` (integer) |  |
`XPATH_BOOLEAN` (integer) |  |
`XPATH_NUMBER` (integer) |  |
`XPATH_STRING` (integer) |  |
`XPATH_POINT` (integer) |  |
`XPATH_RANGE` (integer) |  |
`XPATH_LOCATIONSET` (integer) |  |
`XPATH_USERS` (integer) |  |
`XPATH_NUMBER` (integer) |  |

# Classes

The API of the module follows the DOM Level 2 standard as closely as possible. Consequently, the API is fully object-oriented. It is a good idea to have the DOM standard available when using this module. Though the API is object-oriented, there are many functions which can be called in a non-object-oriented way by passing the object to operate on as the first argument. These functions are mainly to retain compatibility to older versions of the extension, and should not be used when creating new scripts.

This API differs from the official DOM API in two ways. First, all class attributes are implemented as functions with the same name. Secondly, the function names follow the PHP naming convention. This means that a DOM function lastChild() will be written as last_child().

This module defines a number of classes, which are listed - including their method - in the following tables. Classes with an equivalent in the DOM standard are named DOMxxx.

Table 3. List of classes

Class name | Parent classes
--- | ---
DomAttribute | DomNode
DomCData | DomNode
DomComment | DomCData : DomNode
DomDocument | DomNode
DomDocumentType | DomNode
DomElement | DomNode
DomEntity | DomNode
DomEntityReference | DomNode
DomProcessingInstruction | DomNode
DomText | DomCData : DomNode
Parser | Currently still called DomParser
XPathContext |

Table 4. DomDocument class (DomDocument : DomNode)

Method name | Function name | Remark
--- | --- | ---
doctype | DomDocument_doctype() |
document_element | DomDocument_document_element() |
create_element | DomDocument_create_element() |
create_text_node | DomDocument_create_text_node() |
create_comment | DomDocument_create_comment() |
create_cdata_section | DomDocument_create_cdata_section() |
create_processing_instruction | DomDocument_create_processing_instruction() |
create_attribute | DomDocument_create_attribute() |
create_entity_reference | DomDocument_create_entity_reference() |
get_elements_by_tagname | DomDocument_get_elements_by_tagname() |
get_element_by_id | DomDocument_get_element_by_id() |
dump_mem | DomDocument_dump_mem() | not DOM standard
dump_file | DomDocument_dump_file() | not DOM standard
html_dump_mem | DomDocument_html_dump_mem() | not DOM standard
xpath_init | xpath_init | not DOM standard
xpath_new_context | xpath_new_context | not DOM standard
xptr_new_context | xptr_new_context | not DOM standard

Table 5. DomElement class (DomElement : DomNode)

Method name | Function name | Remark
--- | --- | ---
tagname | DomElement_tagname() |
get_attribute | DomElement_get_attribute() |
set_attribute | DomElement_set_attribute() |
remove_attribute | DomElement_remove_attribute() |
get_attribute_node | DomElement_get_attribute_node() |
set_attribute_node | DomElement_set_attribute_node() |
get_elements_by_tagname | DomElement_get_elements_by_tagname() |
has_attribute | DomElement_has_attribute() |

Table 6. DomNode class

Method name | Remark
--- | ---
DomNode_node_name() |
DomNode_node_value() |
DomNode_node_type() |
DomNode_last_child() |
DomNode_first_child() |
DomNode_child_nodes() |
DomNode_previous_sibling() |
DomNode_next_sibling() |
DomNode_parent_node() |
DomNode_owner_document() |
DomNode_insert_before() |
DomNode_append_child() |
DomNode_append_sibling() | Not in DOM standard. This function emulates the former behaviour of DomNode_append_child().
DomNode_remove_child() |
DomNode_has_child_nodes() |
DomNode_has_attributes() |
DomNode_clone_node() |
DomNode_attributes() |
DomNode_unlink_node() | Not in DOM standard
DomNode_replace_node() | Not in DOM standard
DomNode_set_content() | Not in DOM standard, deprecated
DomNode_get_content() | Not in DOM standard, deprecated
DomNode_dump_node() | Not in DOM standard
DomNode_is_blank_node() | Not in DOM standard

Table 7. DomAttribute class (DomAttribute : DomNode)

Method name |  | Remark
--- | --- | ---
name | DomAttribute_name() |
value | DomAttribute_value() |
specified | DomAttribute_specified() |

Table 8. DomProcessingInstruction class (DomProcessingInstruction : DomNode)

Method name | Function name | Remark
--- | --- | ---
target | DomProcessingInstruction_target() |
data | DomProcessingInstruction_data() |

Table 9. Parser class

Method name | Function name | Remark
--- | --- | ---
add_chunk | Parser_add_chunk() |
end | Parser_end() |

Table 10. XPathContext class

Method name | Function name | Remark
--- | --- | ---
eval | XPathContext_eval() |
eval_expression | XPathContext_eval_expression() |
register_ns | XPathContext_register_ns() |

Table 11. DomDocumentType class (DomDocumentType : DomNode)

Method name | Function name | Remark
--- | --- | ---
name | DomDocumentType_name() |
entities | DomDocumentType_entities() |
notations | DomDocumentType_notations() |
public_id | DomDocumentType_public_id() |
system_id | DomDocumentType_system_id() |
internal_subset | DomDocumentType_internal_subset() |

The classes DomDtd is derived from DomNode. DomComment is derived from DomCData.

# Examples

Many examples in this reference require an XML string. Instead of repeating this string in every example, it will be put into a file which will be included by each example. This include file is shown in the following example section. Alternatively, you could create an XML document and read it with DomDocument_open_file().

Example 1. Include file example.inc with XML string
`<?php $xmlstr = "<?xml version='1.0' standalone='yes'?> <!DOCTYPE chapter SYSTEM '/share/sgml/Norman_Walsh/db3xml10/db3xml10.dtd' [ <!ENTITY sp \"spanish\"> ]> <!-- lsfj --> <chapter language='en'><title language='en'>Title</title> <para language='ge'> &sp; <!-- comment --> <informaltable ID='findme' language='&sp;'> <tgroup cols='3'> <tbody> <row><entry>a1</entry><entry morerows='1'>b1</entry><entry>c1</entry></row> <row><entry>a2</entry><entry>c2</entry></row> <row><entry>a3</entry><entry>b3</entry><entry>c3</entry></row> </tbody> </tgroup> </informaltable> </para> </chapter>"; ?>`

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