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이 문서에서는 PHP 중국어 웹사이트 매뉴얼 풀어 주다
此例程用于加亮 XML 代码。举例说明如何使用外部实体引用来包含和解析其他文档, 及处理指令是如何被处理的,及判断处理指令所包含代码是否“可信任”的一种方法
用于此例程的 XML 文档位于此例程的下方(xmltest.xml 和 xmltest2.xml)。
Example #1 外部实体例程
<?php
$file = "xmltest.xml" ;
function trustedFile ( $file )
{
// 仅信任本地文件
if (! preg_match ( "@^([a-z]+)\:\/\/@i" , $file )
&& fileowner ( $file ) == getmyuid ()) {
return true ;
}
return false ;
}
function startElement ( $parser , $name , $attribs )
{
echo "<<font color=\"#0000cc\"> $name </font>" ;
if ( count ( $attribs )) {
foreach ( $attribs as $k => $v ) {
echo " <font color=\"#009900\"> $k </font>=\"<font
color=\"#990000\"> $v </font>\"" ;
}
}
echo ">" ;
}
function endElement ( $parser , $name )
{
echo "</<font color=\"#0000cc\"> $name </font>>" ;
}
function characterData ( $parser , $data )
{
echo "<b> $data </b>" ;
}
function PIHandler ( $parser , $target , $data )
{
switch ( strtolower ( $target )) {
case "php" :
global $parser_file ;
// 如何要解析的文档是“可信任”的, 则说明可安全
// 地执行其内部的 PHP 代码。否则,显示代码内容。
if ( trustedFile ( $parser_file [ $parser ])) {
eval( $data );
} else {
printf ( "Untrusted PHP code: <i>%s</i>" ,
htmlspecialchars ( $data ));
}
break;
}
}
function defaultHandler ( $parser , $data )
{
if ( substr ( $data , 0 , 1 ) == "&" && substr ( $data , - 1 , 1 ) == ";" ) {
printf ( '<font color="#aa00aa">%s</font>' ,
htmlspecialchars ( $data ));
} else {
printf ( '<font size="-1">%s</font>' ,
htmlspecialchars ( $data ));
}
}
function externalEntityRefHandler ( $parser , $openEntityNames , $base , $systemId ,
$publicId ) {
if ( $systemId ) {
if (!list( $parser , $fp ) = new_xml_parser ( $systemId )) {
printf ( "Could not open entity %s at %s\n" , $openEntityNames ,
$systemId );
return false ;
}
while ( $data = fread ( $fp , 4096 )) {
if (! xml_parse ( $parser , $data , feof ( $fp ))) {
printf ( "XML error: %s at line %d while parsing entity %s\n" ,
xml_error_string ( xml_get_error_code ( $parser )),
xml_get_current_line_number ( $parser ), $openEntityNames );
xml_parser_free ( $parser );
return false ;
}
}
xml_parser_free ( $parser );
return true ;
}
return false ;
}
function new_xml_parser ( $file )
{
global $parser_file ;
$xml_parser = xml_parser_create ();
xml_parser_set_option ( $xml_parser , XML_OPTION_CASE_FOLDING , 1 );
xml_set_element_handler ( $xml_parser , "startElement" , "endElement" );
xml_set_character_data_handler ( $xml_parser , "characterData" );
xml_set_processing_instruction_handler ( $xml_parser , "PIHandler" );
xml_set_default_handler ( $xml_parser , "defaultHandler" );
xml_set_external_entity_ref_handler ( $xml_parser , "externalEntityRefHandler" );
if (!( $fp = @ fopen ( $file , "r" ))) {
return false ;
}
if (! is_array ( $parser_file )) {
settype ( $parser_file , "array" );
}
$parser_file [ $xml_parser ] = $file ;
return array( $xml_parser , $fp );
}
if (!(list( $xml_parser , $fp ) = new_xml_parser ( $file ))) {
die( "could not open XML input" );
}
echo "<pre>" ;
while ( $data = fread ( $fp , 4096 )) {
if (! xml_parse ( $xml_parser , $data , feof ( $fp ))) {
die( sprintf ( "XML error: %s at line %d\n" ,
xml_error_string ( xml_get_error_code ( $xml_parser )),
xml_get_current_line_number ( $xml_parser )));
}
}
echo "</pre>" ;
echo "parse complete\n" ;
xml_parser_free ( $xml_parser );
?>
Example #2 xmltest.xml
<?xml version='1.0'?> <!DOCTYPE chapter SYSTEM "/just/a/test.dtd" [ <!ENTITY plainEntity "FOO entity"> <!ENTITY systemEntity SYSTEM "xmltest2.xml"> ]> <chapter> <TITLE>Title &plainEntity;</TITLE> <para> <informaltable> <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> &systemEntity; <section id="about"> <title>About this Document</title> <para> <!-- this is a comment --> <?php echo 'Hi! This is PHP version ' . phpversion(); ?> </para> </section> </chapter>
此文件包含在 xmltest.xml 中:
Example #3 xmltest2.xml
<?xml version="1.0"?> <!DOCTYPE foo [ <!ENTITY testEnt "test entity"> ]> <foo> <element attrib="value"/> &testEnt; <?php echo "This is some more PHP code being executed."; ?> </foo>