CLVIII. XMLReader functions

简介

The XMLReader extension is an XML Pull parser. The reader acts as a cursor going forward on the document stream and stopping at each node on the way.

安装

The XMLReader extension is available in PECL for PHP 5.0 and is included in PHP 5.1 by default. It and can be enabled by adding the argument --with--xmlreader to your configure line. The libxml extension is required.

预定义类

XMLReader

方法

XMLReader->close() - Close the XMLReader input
XMLReader->expand() - Export current node to a DOM node
XMLReader->getAttribute() - Get value of attribute by name
XMLReader->getAttributeNo() - Get value of attribute by position
XMLReader->getAttributeNS() - Get value of attribute by name and URI
XMLReader->getParserProperty() - Indicates if parser property is set or not
XMLReader->isValid() - Indicates if document is valid
XMLReader->lookupNamespace() - Get URI for prefix in scope of node
XMLReader->moveToAttribute() - Positions reader on named attribute
XMLReader->moveToAttributeNo() - Positions reader on attribute by index
XMLReader->moveToAttributeNs() - Position reader on attribute by name and URI
XMLReader->moveToElement() - Move to parent element of current attribute node
XMLReader->moveToFirstAttribute() - Move to first attribute of node
XMLReader->moveToNextAttribute() - Move to next attribute of node
XMLReader->next() - Move to next element skipping children
XMLReader->open() - Set URI to be parsed
XMLReader->read() - Move to next node in stream
XMLReader->setParserProperty() - Set parser property
XMLReader->setRelaxNGSchema() - Set URI of RelaxNG schema to validate against
XMLReader->setRelaxNGSchemaSource() - Set string containing RelaxNG schema to validate against
XMLReader->XML() - Set string of data to be parsed

属性

表格 1.

Name	Type	Read-only	Description
attributeCount	int	yes	The number of attributes on the node
baseURI	string	yes	The base URI of the node
depth	int	yes	Depth of the node in the tree starting at 0
hasAttributes	bool	yes	Indicates if node has attributes
hasValue	bool	yes	Indicates if node has a text value
isDefault	bool	yes	Indicates if attribute is defaulted from DTD
isEmptyElement	bool	yes	Indicates if node is an empty element tag
localName	string	yes	The local name of the node
name	string	yes	The qualified name of the node
namespaceURI	string	yes	The URI of the namespace associated with the node
nodeType	int	yes	The node type for the node
prefix	string	yes	The prefix of the namespace associated with the node
value	string	yes	The text value of the node
xmlLang	string	yes	The xml:lang scope which the node resides

预定义常量

以下常量由本扩展模块定义，因此只有在本扩展模块被编译到 PHP 中，或者在运行时被动态加载后才有效。

表格 2. XMLReader Node Types

Constant	Value	Description
`XMLREADER_NONE` (integer)	0	No node type
`XMLREADER_ELEMENT` (integer)	1	Start element
`XMLREADER_ATTRIBUTE` (integer)	2	Attribute node
`XMLREADER_TEXT` (integer)	3	Text node
`XMLREADER_CDATA` (integer)	4	CDATA node
`XMLREADER_ENTITY_REF` (integer)	5	Entity Reference node
`XMLREADER_ENTITY` (integer)	6	Entity Declaration node
`XMLREADER_PI` (integer)	7	Processing Instruction node
`XMLREADER_COMMENT` (integer)	8	Comment node
`XMLREADER_DOC` (integer)	9	Document node
`XMLREADER_DOC_TYPE` (integer)	10	Document Type node
`XMLREADER_DOC_FRAGMENT` (integer)	11	Document Fragment node
`XMLREADER_NOTATION` (integer)	12	Notation node
`XMLREADER_WHITESPACE` (integer)	13	Whitespace node
`XMLREADER_SIGNIFICANT_WHITESPACE` (integer)	14	Significant Whitespace node
`XMLREADER_END_ELEMENT` (integer)	15	End Element
`XMLREADER_END_ENTITY` (integer)	16	End Entity
`XMLREADER_XML_DECLARATION` (integer)	17	XML Declaration node

表格 3. XMLReader Parser Options

Constant	Value	Description
`XMLREADER_LOADDTD` (integer)	1	Load DTD but do not validate
`XMLREADER_DEFAULTATTRS` (integer)	2	Load DTD and default attributes but do not validate
`XMLREADER_VALIDATE` (integer)	3	Load DTD and validate while parsing
`XMLREADER_SUBST_ENTITIES` (integer)	4	Subsitute entities and expand references

目录
XMLReader->close() -- Close the XMLReader input
XMLReader->expand() -- Returns a copy of the current node as a DOM object
XMLReader->getAttribute() -- Get the value of a named attribute
XMLReader->getAttributeNo() -- Get the value of an attribute by index
XMLReader->getAttributeNS() -- Get the value of an attribute by localname and URI
XMLReader->getParserProperty() -- Indicates if specified property has been set
XMLReader->isValid() -- Indicates if the parsed document is valid
XMLReader->lookupNamespace() -- Lookup namespace for a prefix
XMLReader->moveToAttribute() -- Move cursor to a named attribute
XMLReader->moveToAttributeNo() -- Move cursor to an attribute by index
XMLReader->moveToAttributeNs() -- Move cursor to a named attribute
XMLReader->moveToElement() -- Position cursor on the parent Element of current Attribute
XMLReader->moveToFirstAttribute() -- Position cursor on the first Attribute
XMLReader->moveToNextAttribute() -- Position cursor on the next Attribute
XMLReader->next() -- Move cursor to next node skipping all subtrees
XMLReader->open() -- Set the URI containing the XML to parse
XMLReader->read() -- Move to next node in document
XMLReader->setParserProperty() -- Set or Unset parser options
XMLReader->setRelaxNGSchema() -- Set the filename or URI for a RelaxNG Schema
XMLReader->setRelaxNGSchemaSource() -- Set the data containing a RelaxNG Schema
XMLReader->XML() -- Set the data containing the XML to parse

add a note User Contributed Notes

jcatalaa at catium dot com
21-Mar-2006 03:52


DTD Validation



Parser properties can be set using:



  $xml_reader->setParserProperty(XMLReader::CONSTANT_NAME, BoolenValue);



The constant setting in the xmlreader_validatedtd.php example that comes

with the xmlread package results in an error.

Here is how I got it to work...



<?php

$indent = 5; /* Number of spaces to indent per level */



$xml = new XMLReader();

$xml->open("dtdexample.xml");

// CHANGED NEXT TWO LINES TO REMOVE ERROR

// FROM: $xml->setParserProperty(XMLREADER_LOADDTD, TRUE);

$xml->setParserProperty(XMLReader::LOADDTD,  TRUE); 

$xml->setParserProperty(XMLReader::VALIDATE, TRUE);

while($xml->read()) {

    /* Print node name indenting it based on depth and $indent var */

    print str_repeat(" ", $xml->depth * $indent).$xml->name."\n";

    if ($xml->hasAttributes) {

        $attCount = $xml->attributeCount;

        print str_repeat(" ", $xml->depth * $indent)." Number of Attributes: ".$xml->attributeCount."\n";

    }

}

print "\n\nValid:\n";

var_dump($xml->isValid());

?>

orion at ftf-hq dot dk
15-Feb-2006 08:50


Some more documentation (i.e. examples) would be nice :-)



This is how I read some mysql parameters in an xml file:



<?php

    $xml = new XMLReader();

    $xml->open("config.xml");

    $xml->setParserProperty(2,true); // This seems a little unclear to me - but it worked :)



    while ($xml->read()) {

        switch ($xml->name) {

        case "mysql_host":

            $xml->read();

            $conf["mysql_host"] = $xml->value;

            $xml->read();

            break;

        case "mysql_username":

            $xml->read();

            $conf["mysql_user"] = $xml->value;

            $xml->read();

            break;

        case "mysql_password":

            $xml->read();

            $conf["mysql_pass"] = $xml->value;

            $xml->read();

            break;

        case "mysql_database":

            $xml->read();

            $conf["mysql_db"] = $xml->value;

            $xml->read();

            break;

        }

    }



    $xml->close();

?>



The XML file used:

<?xml version='1.0'?>

<MySQL_INIT>

   <mysql_host>localhost</mysql_host>

   <mysql_database>db_database</mysql_database>

   <mysql_username>root</mysql_username>

   <mysql_password>password</mysql_password>

</MySQL_INIT>

Ariel Gonzalez
12-Feb-2006 06:09


Simple function I used while playing around with XMLReader.



<?php

function dump_xmlreader($o) {

    $node_types = array (

        0=>"No node type",

        1=>"Start element",

        2=>"Attribute node",

        3=>"Text node",

        4=>"CDATA node",

        5=>"Entity Reference node",

        6=>"Entity Declaration node",

        7=>"Processing Instruction node",

        8=>"Comment node",

        9=>"Document node",

        10=>"Document Type node",

        11=>"Document Fragment node",

        12=>"Notation node",

        13=>"Whitespace node",

        14=>"Significant Whitespace node",

        15=>"End Element",

        16=>"End Entity",

        17=>"XML Declaration node"

    );



    echo "attributeCount = " . $o->attributeCount . "\n";

    echo "baseURI = " . $o->baseURI . "\n";

    echo "depth = " . $o->depth . "\n";

    echo "hasAttributes = " . ( $o->hasAttributes ? 'TRUE' : 'FALSE' ) . "\n";

    echo "hasValue = " . ( $o->hasValue ? 'TRUE' : 'FALSE' ) . "\n";

    echo "isDefault = " . ( $o->isDefault ? 'TRUE' : 'FALSE' ) . "\n";

    echo "isEmptyElement = " . ( @$o->isEmptyElement ? 'TRUE' : 'FALSE' ) . "\n";

    echo "localName = " . $o->localName . "\n";

    echo "name = " . $o->name . "\n";

    echo "namespaceURI = " . $o->namespaceURI . "\n";

    echo "nodeType = " . $o->nodeType . ' - ' . $node_types[$o->nodeType] . "\n";

    echo "prefix = " . $o->prefix . "\n";

    echo "value = " . $o->value . "\n";

    echo "xmlLang = " . $o->xmlLang . "\n";

}

?>

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