xml_set_element_handler

(PHP 4, PHP 5)

xml_set_element_handlerSet up start and end element handlers

Description

bool xml_set_element_handler ( resource $parser , callable $start_element_handler , callable $end_element_handler )

Sets the element handler functions for the XML parser. start_element_handler and end_element_handler are strings containing the names of functions that must exist when xml_parse() is called for parser.

Parameters

parser

A reference to the XML parser to set up start and end element handler functions.

start_element_handler

The function named by start_element_handler must accept three parameters:

start_element_handler ( resource $parser , string $name , array $attribs )
parser
The first parameter, parser, is a reference to the XML parser calling the handler.
name
The second parameter, name, contains the name of the element for which this handler is called.If case-folding is in effect for this parser, the element name will be in uppercase letters.
attribs
The third parameter, attribs, contains an associative array with the element's attributes (if any).The keys of this array are the attribute names, the values are the attribute values.Attribute names are case-folded on the same criteria as element names.Attribute values are not case-folded. The original order of the attributes can be retrieved by walking through attribs the normal way, using each().The first key in the array was the first attribute, and so on.

Note: Instead of a function name, an array containing an object reference and a method name can also be supplied.

end_element_handler

The function named by end_element_handler must accept two parameters:

end_element_handler ( resource $parser , string $name )
parser
The first parameter, parser, is a reference to the XML parser calling the handler.
name
The second parameter, name, contains the name of the element for which this handler is called.If case-folding is in effect for this parser, the element name will be in uppercase letters.

If a handler function is set to an empty string, or FALSE, the handler in question is disabled.

Return Values

Returns TRUE on success or FALSE on failure.

Коментарии

Автор:
If you are using a class for xml parsing, and want to check the return value of xml_set_element_handler in case it  fails, you must do this outside of the class's constructor. Inside the constructor, PHP-4.0.5 will die.

Basically, put all your xml initialisation code in another function of the class, and keep it out of the constructor.
2001-05-07 14:08:35
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
Автор:
You CAN use classes to parse XML. Just take a look at the following function:

xml_set_object
2001-10-11 07:09:52
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
It seems that the tag handlers don't block on one another (the end handler is called whether or not the begin handler has finished). this can put you in a tight spot if you don't realize it while planning your app.
2003-01-31 13:22:02
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
In response to landb at mail dot net...

As the notes mention, you can pass an array that contains the reference to an object and a method name when you need... so you can call methods in your own class as handlers like this:

xml_set_element_handler($parser, array($this,"_startElement"), array($this,"_endElement"));

Hope it helps...
2004-10-21 11:40:36
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
Автор:
In response to aw at avatartechnology dot com...
In response to landb at mail dot net...

When your functions are in an object:
Careful ! Don't forget to add: & (reference) to your parameters.

xml_set_element_handler($parser, array(&$this,"_startElement"), array(&$this,"_endElement"));
--> xmlparse will work on your object (good).

instead of:
xml_set_element_handler($parser, array($this,"_startElement"), array($this,"_endElement"));
---> xmlparse will work on a COPY of your object (often bad)

Vin-s
(sorry for my english)
2005-03-13 15:34:32
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
<html> 
  <head> 
    <title>SAX Demonstration</title> 
   <META HTTP-EQUIV='Content-type' CONTENT='text/html; charset=euc-kr'> 
  </head> 
  <body> 
    <h1>RSS ??????</h1> 
   
      <?php 

     $file 
"data.xml"
     
     
$currentTag ""
     
$currentAttribs ""

      function 
startElement($parser$name$attribs
      { 
          global 
$currentTag$currentAttribs
         
$currentTag $name
   
         
$currentAttribs $attribs
          switch (
$name) { 
         
          default: 
              echo(
"<b>&lt$name&gt</b><br>"); 
              break; 
          } 
      } 

      function 
endElement($parser$name
      { 
          global 
$currentTag
          switch (
$name) { 
          default: 
              echo(
"<br><b>&lt/$name&gt</b><br><br>"); 
              break; 
          } 
         
$currentTag ""
         
$currentAttribs ""
      } 

      function 
characterData($parser$data
      { 
          global 
$currentTag
          switch (
$currentTag) { 
          case 
"link"
              echo(
"<a href=\"$data\">$data</a>\n"); 
              break; 
          case 
"title"
              echo(
"title : $data"); 
              break; 
          default: 
              echo(
$data); 
              break; 
          } 
      } 

     
$xmlParser xml_parser_create(); 
   
     
$caseFold xml_parser_get_option($xmlParser
                                       
XML_OPTION_CASE_FOLDING); 
   
     
$targetEncoding xml_parser_get_option($xmlParser
                                             
XML_OPTION_TARGET_ENCODING); 

      if (
$caseFold == 1) { 
         
xml_parser_set_option($xmlParserXML_OPTION_CASE_FOLDINGfalse); 
      } 

     
xml_set_element_handler($xmlParser"startElement""endElement"); 
     
xml_set_character_data_handler($xmlParser"characterData"); 

      if (!(
$fp fopen($file"r"))) { 
          die(
"Cannot open XML data file: $file"); 
      } 

     while (
$data fread($fp4096)) { 
          if (!
xml_parse($xmlParser$datafeof($fp))) { 
              die(
sprintf("XML error: %s at line %d"
                         
xml_error_string(xml_get_error_code($xmlParser)), 
                         
xml_get_current_line_number($xmlParser))); 
             
xml_parser_free($xmlParser); 
          } 
      } 
     
xml_parser_free($xmlParser); 
     
?> 
    </table> 
  </body> 
</html>
2005-04-30 06:41:26
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
I noticed that in the example below, and all the examples I've seen on this site for viewing xml in html, the look of self closing tags such as <br /> are not preserved. The parser cannot distinguish between <tag /> and <tag></tag>, and if your start and end element functions are like these examples, both instances will be output with both an indvidual start and end tag.  I needed to preserve self-closing tags and it took me a while to figure out this work around. Hope this helps someone...
 
The start tag is left open, and then completed by it's first child, the next start tag or its end tag.  The end tag will complete with " />", or </tag> depending on the number of bytes between the start and end tags in the parsed data.
<?php
//$data=filepath or string
$data=<<<DATA
<normal_tag>
  <self_close_tag />
      data
  <normal_tag>data
     <self_close_tag attr="value" />
  </normal_tag>
      data
  <normal_tag></normal_tag>
</normal_tag>
DATA;

function 
startElement($parser$name$attrs)
{
       
xml_set_character_data_handler($parser"characterData");
        global 
$first_child$start_byte;
        if(
$first_child)          //close start tag if neccessary
               
echo "><br />";
       
$first_child=true;
       
$start_byte=xml_get_current_byte_index ($parser);
        if(
count($attrs)>=1){
                foreach(
$attrs as $x=>$y){
                       
$attr_string .= $x=\"$y\"";
                }
        }
        echo 
htmlentities("<{$name}{$attr_string}"); //unclosed starttag
}

function 
endElement($parser$name)
{
        global 
$first_child$start_byte;
       
$byte=xml_get_current_byte_index ($parser);
        if(
$byte-$start_byte>2){           //if end tag is more than 2 bytes from start tag
               
if($first_child)          //close start tag if neccessary
                       
echo "><br />";
                echo 
htmlentities("</{$name}>")."<br />"//individual end tag
       
}else
                echo 
" /><br />"// self closing tag
       
$first_child=false;

}

function 
characterData($parser$data)
{
        global 
$first_child;
        if(
$first_child//if $data is first child, close start tag
               
echo "><br />";
        if(
$data=trim($data))
                echo 
"<font color='blue'>$data</font><br />";
       
$first_child=false;
}

function 
ParseData($data)
{
       
$xml_parser xml_parser_create();
       
xml_set_element_handler($xml_parser"startElement""endElement");
       
xml_parser_set_option($xml_parser,XML_OPTION_CASE_FOLDING,0);
        if(
is_file($data))
        {
                if (!(
$fp fopen($file"r"))) {
                        die(
"could not open XML input");
                }

                while (
$data fread($fp4096)) {
                        if (!
xml_parse($xml_parser$datafeof($fp))) {
                               
$error=xml_error_string(xml_get_error_code($xml_parser));
                               
$line=xml_get_current_line_number($xml_parser);
                                die(
sprintf("XML error: %s at line %d",$error,$line));
                        }
                }
        }else{
                if (!
xml_parse($xml_parser$data1)) {
                               
$error=xml_error_string(xml_get_error_code($xml_parser));
                               
$line=xml_get_current_line_number($xml_parser);
                                die(
sprintf("XML error: %s at line %d",$error,$line));
                }
        }
       
       
xml_parser_free($xml_parser);
}

ParseData($data);
?>
2005-08-01 06:49:29
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
The method that 'ibjoel at hotmail dot com' have described requires libxml2 as the xml parser, it does not work with expat. For a brief explanation, see xml_get_current_byte_index.
2005-09-20 06:41:50
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
I ran into the same problem with 'ibjoel at hotmail dot com' in regards to self-closing tags, and found that the script that he/she wrote did not work as I expected.
I played around with some of php's functions and examples and compiled something, which may not be the neatest solution, but it works for the data that 'ibjoel at hotmail dot com' provided.
The data needs to be read from a file though, so the fp can be utilised. It still uses the xml_get_current_byte_index(resource parser) trick, but this time, I check for the last 2 character before the index and test if it's "/>".

<?php
/* myxmltest.xml:
<normal_tag>
  <self_close_tag />
     data
  <normal_tag>data
     <self_close_tag attr="value" />
  </normal_tag>
     data
  <normal_tag></normal_tag>
</normal_tag>
*/

//## Global Variables ##//
$file "myxmltest.xml";
$character_data_on false;
$tag_complete true;

function 
startElement($parser$name$attrs
{
    global 
$character_data_on;
    global 
$tag_complete;
   
    echo 
"&lt;<font color=\"#0000cc\">$name</font>";
   
//## Print the attributes ##//
   
if (sizeof($attrs)) {
        while (list(
$k$v) = each($attrs)) {
            echo 
" <font color=\"#009900\">$k</font>=\"<font 
                   color=\"#990000\">
$v</font>\"";
        }
    }
   
//## Tag is still still incomplete,
    //## will be completed at either endElement or characterData ##//
   
$tag_complete false;
   
$character_data_on false;
}

function 
endElement($parser$name
{
    global 
$fp;
    global 
$character_data_on;
    global 
$tag_complete;
   
   
//#### Test for self-closing tag ####//
    //## xml_get_current_byte_index(resource parser) when run in this
    //## function, gives the index at (indicated by *):
    //##   for self closing tag: <br />*
    //##   for individual closing tag: <div>character data*</div>
    //## So to test for self-closing tag, we can just test for the last 2 
    //## characters from the index
    //###################################//
   
   
if (!$character_data_on) {
       
//## Record current fp position ##//
       
$temp_fp ftell($fp);
       
       
//## Point fp to 2 bytes before the end element byte index ##//
       
$end_element_byte_index xml_get_current_byte_index($parser);
       
fseek($fp,$end_element_byte_index-2);
       
       
//## Gets the last 2 characters before the end element byte index ##//
       
$validator fgets($fp3);
       
       
//## Restore fp position ##//
       
fseek($fp,$temp_fp);
       
       
//## If the last 2 character is "/>" ##//
       
if ($validator=="/>") {
           
//// Complete the self-closing tag ////
           
echo " /&gt";
           
//// Otherwise it is an individual closing tag ////
       
} else echo "&gt&lt/<font color=\"#0000cc\">$name</font>&gt";
       
$tag_complete true;
    } else echo 
"&lt/<font color=\"#0000cc\">$name</font>&gt";
   
   
$character_data_on false;
}

function 
characterData($parser$data
{
    global 
$character_data_on;
    global 
$tag_complete;
   
    if ((!
$character_data_on)&&(!$tag_complete)) {
        echo 
"&gt";
       
$tag_complete true;
    }
    echo 
"<b>$data</b>"
   
$character_data_on true;
}

$xml_parser xml_parser_create();
xml_parser_set_option($xml_parserXML_OPTION_CASE_FOLDINGfalse);
xml_set_element_handler($xml_parser"startElement""endElement");
xml_set_character_data_handler($xml_parser"characterData");
if (!(
$fp fopen($file"r"))) {
    die(
"could not open XML input");
}

echo 
"<pre>";
while (
$file_content fread($fp4096)) {
    if (!
xml_parse($xml_parser$file_contentfeof($fp))) {
        die(
sprintf("XML error: %s at line %d",
                   
xml_error_string(xml_get_error_code($xml_parser)),
                   
xml_get_current_line_number($xml_parser)));
    }
}
echo 
"</pre>";
xml_parser_free($xml_parser);
?>
2005-11-19 10:10:03
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
It seems that characterData() gets characters in chuncks of 1024; therefore if you have string of characters between you tags that is longer than 1024 then characterData() will be called more that once for single pair of tags. I don't know if this feature(bug?) is documented anywhere, I just wanted to warn everyone about this; it had tripped me. I use php 4.3.10 on Linux.
2005-12-13 11:44:39
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
Автор:
Example below (BadParser) works fine with some changes.

xml_set_element_handler ( $parser, array ( &$this, 'tagStart' ), array ( &$this, 'tagEnd' ) );
xml_set_character_data_handler ( $parser, array ( &$this, 'tagContent' ) );
2006-05-15 08:48:06
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
My 25 cents. This example show how to parse a XML in a associative array tree.

<?php

$file 
"flow/flow.xml";
$depth 0;
$tree = array();
$tree['name'] = "root"
$stack[count($stack)] = &$tree;

function 
startElement($parser$name$attrs) {
   global 
$depth;
   global 
$stack;
   global 
$tree;
   
   
$element = array();
   
$element['name'] = $name;
   foreach (
$attrs as $key => $value) { 
       
//echo $key."=".$value;
       
$element[$key]=$value;
    }

   
$last = &$stack[count($stack)-1];
   
$last[count($last)-1] = &$element;
   
$stack[count($stack)] = &$element;

   
$depth++;
}

function 
endElement($parser$name) {
   global 
$depth;
   global 
$stack;

   
array_pop($stack);
   
$depth--;
}

$xml_parser xml_parser_create();
xml_set_element_handler($xml_parser"startElement""endElement");
if (!(
$fp fopen($file"r"))) {
   die(
"could not open XML input");
}

while (
$data fread($fp4096)) {
   if (!
xml_parse($xml_parser$datafeof($fp))) {
       die(
sprintf("XML error: %s at line %d",
                   
xml_error_string(xml_get_error_code($xml_parser)),
                   
xml_get_current_line_number($xml_parser)));
   }
}
xml_parser_free($xml_parser);
$tree $stack[0][0];
echo 
"<pre>";
print_r($tree);
echo 
"</pre>";
2006-08-29 16:44:12
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
I modified the previous script, so that it is associative. I find it more useful that way. BTW I prefer strtolower() things, but that's not mandatory at all.

<?php

$file 
"data.xml";
$depth 0;
$tree = array();
$tree['name'] = "root";
$stack[] = &$tree;

function 
startElement($parser$name$attrs) {
   global 
$depth;
   global 
$stack;
   global 
$tree;
 
   
$element = array();
   foreach (
$attrs as $key => $value) {
       
$element[strtolower($key)]=$value;
   }

   
end($stack);
   
$stack[key($stack)][strtolower($name)] = &$element;
   
$stack[strtolower($name)] = &$element;
   
   
$depth++;
}

function 
endElement($parser$name) {
   global 
$depth;
   global 
$stack;

   
array_pop($stack);
   
$depth--;
}

$xml_parser xml_parser_create();
xml_set_element_handler($xml_parser"startElement""endElement");
if (!(
$fp fopen($file"r"))) {
   die(
"could not open XML input");
}

while (
$data fread($fp4096)) {
   if (!
xml_parse($xml_parser$datafeof($fp))) {
       die(
sprintf("XML error: %s at line %d",
                   
xml_error_string(xml_get_error_code($xml_parser)),
                   
xml_get_current_line_number($xml_parser)));
   }
}
xml_parser_free($xml_parser);
$tree end(end($stack));
echo 
"<pre>";
print_r($tree);
echo 
"</pre>";

?>
2006-10-31 05:07:41
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
This documentation is somewhat awry. I know it's been said many times before, but it bears repeating...

If using PHP4, you may be required to use xml_set_object() instead of calling any of the xml_set_*_handler() functions with a two-item array. It will work fine on PHP5, but move the same code to PHP4 and it will create one copie of $this (even if you use &$this) for each handler you set!

<?php
// This code will fail mysteriously on PHP4.
$this->parser xml_parser_create();
xml_set_element_handler(
           
$this->parser,
            array(&
$this,"start_tag"),
            array(&
$this,"end_tag")
        );
       
xml_set_character_data_handler(
           
$this->parser,
            array(&
$this,"tag_data")
        );
?>

<?php
// This code will work on PHP4.
$this->parser xml_parser_create();
xml_set_object($this->parser,&$this); 
xml_set_element_handler(
           
$this->parser,
           
"start_tag",
           
"end_tag"
       
);
       
xml_set_character_data_handler(
           
$this->parser,
           
"tag_data"
       
);
?>
2007-02-12 12:48:35
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html
Here is another example of detecting empty elements. I works with libxml2. Note that it handles buffer boundaries.

<?php

$depth 
0//current depth, used for pretty printing
$empty false//whether the tag is empty
$offset 0//the index of the start of the current buffer within the stream

function tagStart($parser$name, array $attribs) {
    global 
$depth$empty$data$offset$lastchar;
   
$idx xml_get_current_byte_index($parser);
   
/* xml_get_current_byte_index returns index within the streams and not
       within the buffer.*/
   
    /* Check if the index is within the buffer. */
   
if (isset($data[$idx $offset])) {
       
$c $data[$idx $offset];
    } else {
       
/* If it isn't simple use the last character of the buffer. */
       
$c $lastchar;
    }
   
$empty $c == '/';
    echo 
str_repeat("\t"$depth), "<$name", ($empty '/>' '>'), "\n";
    if (!
$empty) ++$depth;
}

function 
tagEnd($parser$name) {
    global 
$depth$empty;
    if (!
$empty) {
        --
$depth;
        echo 
str_repeat("\t"$depth), "</$name>\n";
    } else {
       
$empty false;
    }
}

$parser xml_parser_create();
xml_parser_set_option($parserXML_OPTION_CASE_FOLDINGfalse);
xml_set_element_handler($parser'tagStart''tagEnd');

$data1 '
<test>
    <empty att="3" />
    <nocontent></nocontent>
    <content>
        <empty/>
        <empty/>
    </content>
    <empty/'
;

$data2 '>
    <empty att="5" />
</test>
'
;

$data = &$data1;
$length strlen($data1);
$lastchar $data[$length-1];
xml_parse($parser$data1);
$offset .= $length;
$data = &$data2;
xml_parse($parser$data2);
2008-09-26 09:44:42
http://php5.kiev.ua/manual/ru/function.xml-set-element-handler.html

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