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XML Parser Funktionen

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Glen at ITIstudios dot ca
24.12.2010 9:35
A working xml to array parser.
Modeled after the previous post it is functionally different as follows:
1. Will always return an array.
2. Includes the content from all elements.
3. Includes all multiple elements in the same array.
4. Has been thoroughly tested before being posted.

Notes:
1. Ignores content that is not in between it's own set of tags.
2. 'attrib' and 'cdata' are keys added to the array when the element contains both attributes and content.

Usage:
  $domObj = new xmlToArrayParser($xml);
  $domArr = $domObj->array;

eg.
  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
  <top>
    <element1>element content 1</element1>
    <element2 var2="val2" />
    <element3 var3="val3" var4="val4">element content 3</element3>
    <element3 var5="val5">element content 4</element3>
    <element3 var6="val6" />
    <element3>element content 7</element3>
  </top>
 
  $domArr['top']['element1'] => element content 1
  $domArr['top']['element2']['attrib']['var2'] => val2
  $domArr['top']['element3']['0']['attrib']['var3'] => val3
  $domArr['top']['element3']['0']['attrib']['var4'] => val4
  $domArr['top']['element3']['0']['cdata'] => element content 3
  $domArr['top']['element3']['1']['attrib']['var5'] => val5
  $domArr['top']['element3']['1']['cdata'] => element content 4
  $domArr['top']['element3']['2']['attrib']['var6'] => val6
  $domArr['top']['element3']['3'] => element content 7

Note: If your output contains something like this "é" which is supposed to be the letter "é" make sure your character set is UTF-8.
eg. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

<?php
/**
 * Convert an xml file to an associative array (including the tag attributes):
 *
 * @param Str $xml file/string.
 */
class xmlToArrayParser {
 
/**
   * The array created by the parser which can be assigned to a variable with: $varArr = $domObj->array.
   *
   * @var Array
   */
 
public  $array;
  private
$parser;
  private
$pointer;

 
/**
   * $domObj = new xmlToArrayParser($xml);
   *
   * @param Str $xml file/string
   */
 
public function __construct($xml) {
   
$this->pointer =& $this->array;
   
$this->parser = xml_parser_create("UTF-8");
   
xml_set_object($this->parser, $this);
   
xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING, false);
   
xml_set_element_handler($this->parser, "tag_open", "tag_close");
   
xml_set_character_data_handler($this->parser, "cdata");
   
xml_parse($this->parser, ltrim($xml));
  }

  private function
tag_open($parser, $tag, $attributes) {
   
$this->convert_to_array($tag, '_');
   
$idx=$this->convert_to_array($tag, 'cdata');
    if(isset(
$idx)) {
     
$this->pointer[$tag][$idx] = Array('@idx' => $idx,'@parent' => &$this->pointer);
     
$this->pointer =& $this->pointer[$tag][$idx];
    }else {
     
$this->pointer[$tag] = Array('@parent' => &$this->pointer);
     
$this->pointer =& $this->pointer[$tag];
    }
    if (!empty(
$attributes)) { $this->pointer['_'] = $attributes; }
  }

 
/**
   * Adds the current elements content to the current pointer[cdata] array.
   */
 
private function cdata($parser, $cdata) {
    if(isset(
$this->pointer['cdata'])) { $this->pointer['cdata'] .= $cdata;}
    else {
$this->pointer['cdata'] = $cdata;}
  }

  private function
tag_close($parser, $tag) {
   
$current = & $this->pointer;
    if(isset(
$this->pointer['@idx'])) {unset($current['@idx']);}
   
$this->pointer = & $this->pointer['@parent'];
    unset(
$current['@parent']);
    if(isset(
$current['cdata']) && count($current) == 1) { $current = $current['cdata'];}
    else if(empty(
$current['cdata'])) { unset($current['cdata']); }
  }

 
/**
   * Converts a single element item into array(element[0]) if a second element of the same name is encountered.
   */
 
private function convert_to_array($tag, $item) {
    if(isset(
$this->pointer[$tag][$item])) {
     
$content = $this->pointer[$tag];
     
$this->pointer[$tag] = array((0) => $content);
     
$idx = 1;
    }else if (isset(
$this->pointer[$tag])) {
     
$idx = count($this->pointer[$tag]);
      if(!isset(
$this->pointer[$tag][0])) {
        foreach (
$this->pointer[$tag] as $key => $value) {
            unset(
$this->pointer[$tag][$key]);
           
$this->pointer[$tag][0][$key] = $value;
    }}}else
$idx = null;
    return
$idx;
  }
}
?>
wolfon.AT-DoG.inbox.ru
29.07.2008 0:09
Finally a simple xml => array class.
Functioning like SimpleXML library.

<?php
class xml  {
    private
$parser;
    private
$pointer;
    public
$dom;
   
    public function
__construct($data) {
       
$this->pointer =& $this->dom;
       
$this->parser = xml_parser_create();
       
xml_set_object($this->parser, $this);
       
xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING, false);
       
xml_set_element_handler($this->parser, "tag_open", "tag_close");
       
xml_set_character_data_handler($this->parser, "cdata");
       
xml_parse($this->parser, $data);
    }
  
    private function
tag_open($parser, $tag, $attributes) {
        if (isset(
$this->pointer[$tag]['@attributes'])) {
           
$content = $this->pointer[$tag];
           
$this->pointer[$tag] = array(0 => $content);
           
$idx = 1;
        } else if (isset(
$this->pointer[$tag]))
           
$idx = count($this->pointer[$tag]);

        if (isset(
$idx)) {
           
$this->pointer[$tag][$idx] = Array(
               
'@idx' => $idx,
               
'@parent' => &$this->pointer);
              
$this->pointer =& $this->pointer[$tag][$idx];
        } else {
           
$this->pointer[$tag] = Array(
               
'@parent' => &$this->pointer);
           
$this->pointer =& $this->pointer[$tag];
        }
        if (!empty(
$attributes))
           
$this->pointer['@attributes'] = $attributes;
    }

    private function
cdata($parser, $cdata) {
          
$this->pointer['@data'] = $cdata;
    }

    private function
tag_close($parser, $tag) {
       
$current = & $this->pointer;
        if (isset(
$this->pointer['@idx']))
            unset(
$current['@idx']);
       
       
$this->pointer = & $this->pointer['@parent'];
       
          unset(
$current['@parent']);
           if (isset(
$current['@data']) && count($current) == 1)
              
$current = $current['@data'];
           else if (empty(
$current['@data'])||$current['@data']==0)
               unset(
$current['@data']);
    }
}
?>

maybe I'll do some explanations on habr
geoff at spacevs dot com
8.11.2007 6:13
Reading xml into a class:

<?PHP
       
class XmlData {}
       
$elements = array();
       
$elements[] =& new XmlData();
        function
startElement($parser, $name, $attrs) {
                global
$elements;
               
$element =& new XMLData();
               
$elements[count($elements)-1]->$name =& $element;
               
$elements[] =& $element;
        }
        function
endElement($parser, $name) {
                global
$elements;
               
array_pop($elements);
        }
        function
characterData($parser, $data) {
                global
$elements;
               
$elements[count($elements)-1]->data = $data;
        }
       
$xml_parser     = xml_parser_create();
       
xml_set_element_handler($xml_parser, "startElement", "endElement");
       
xml_set_character_data_handler($xml_parser, "characterData");
       
xml_parse($xml_parser, $xml, true);
       
xml_parser_free($xml_parser);
       
$request =& array_pop($elements);

        echo
$request->LOGIN->USER->data;
?>
demonpants at gmail dot com
23.10.2007 5:59
I wanted to access the ISBN database, and was previously parsing the HTML string generated from their main page, that is until I discovered they have an API that returns XML.

So, if anyone wants to get some information from the ISBN database, all you need to do is the following.

<?php
//Search the ISBN database for the book.
           
$url = "http://www.isbndb.com/api/books.xml? access_key=KEY&index1=isbn&value1=$_GET[ISBN]";
           
$p = xml_parser_create();
           
xml_parse_into_struct($p,file_get_contents($url),$results,$index);
           
xml_parser_free($p);

           
$title = $results[$index[TITLELONG][0]][value];
           
$author = $results[$index[AUTHORSTEXT][0]][value];
           
$publisher = $results[$index[PUBLISHERTEXT][0]][value];
?>

You will need to get an access key from isbndb.com, but it takes two seconds and is free. When you get it, replace KEY in the URL with your own key. Also, my code above will search for the book that fits the ISBN number stored in the GET variable ISBN - you can search by other parameters and return more than one result, but my example is  for a simple ISBN search.
Zvjezdan Patz
9.09.2007 17:22
The problem I had was I needed to generate xml on the screen for users to actually see and copy to a file. 

I'm generating the xml manually from a php file and the browser kept interpreting the xml...not very helpful. 

This is how you get around it:

<?php

$file 
= file_get_contents("http://example.com/xml.php?whatever=$whatever");
print
nl2br(htmlentities($file));

?>

Prints all my xml quite nicely.
v9 at fakehalo dot us
14.07.2007 5:04
I needed this for work/personal use.  Sometimes you'll have a XML string generated as one long string and no line breaks...nusoap in the case of today/work, but there are any other number of possible things that will generate these.  Anyways, this simply takes a long XML string and returns an indented/line-breaked version of the string for display/readability.

<?php
function xmlIndent($str){
   
$ret = "";
   
$indent = 0;
   
$indentInc = 3;
   
$noIndent = false;
    while((
$l = strpos($str,"<",$i))!==false){
        if(
$l!=$r && $indent>0){ $ret .= "\n" . str_repeat(" ",$indent) . substr($str,$r,($l-$r)); }
       
$i = $l+1;
       
$r = strpos($str,">",$i)+1;
       
$t = substr($str,$l,($r-$l));
        if(
strpos($t,"/")==1){
           
$indent -= $indentInc;
           
$noIndent = true;
        }
        else if((
$r-$l-strpos($t,"/"))==2 || substr($t,0,2)=="<?"){ $noIndent = true; }
        if(
$indent<0){ $indent = 0; }
        if(
$ret){ $ret .= "\n"; }
       
$ret .= str_repeat(" ",$indent);
       
$ret .= $t;
        if(!
$noIndent){ $indent += $indentInc; }
       
$noIndent = false;
    }
   
$ret .= "\n";
    return(
$ret);
}
?>

(...this was only tested for what i needed at work, could POSSIBLY need additions)
geoffers [at] gmail [dot] com
31.12.2006 0:27
Time to add my attempt at a very simple script that parses XML into a structure:

<?php

class Simple_Parser
{
    var
$parser;
    var
$error_code;
    var
$error_string;
    var
$current_line;
    var
$current_column;
    var
$data = array();
    var
$datas = array();
   
    function
parse($data)
    {
       
$this->parser = xml_parser_create('UTF-8');
       
xml_set_object($this->parser, $this);
       
xml_parser_set_option($this->parser, XML_OPTION_SKIP_WHITE, 1);
       
xml_set_element_handler($this->parser, 'tag_open', 'tag_close');
       
xml_set_character_data_handler($this->parser, 'cdata');
        if (!
xml_parse($this->parser, $data))
        {
           
$this->data = array();
           
$this->error_code = xml_get_error_code($this->parser);
           
$this->error_string = xml_error_string($this->error_code);
           
$this->current_line = xml_get_current_line_number($this->parser);
           
$this->current_column = xml_get_current_column_number($this->parser);
        }
        else
        {
           
$this->data = $this->data['child'];
        }
       
xml_parser_free($this->parser);
    }

    function
tag_open($parser, $tag, $attribs)
    {
       
$this->data['child'][$tag][] = array('data' => '', 'attribs' => $attribs, 'child' => array());
       
$this->datas[] =& $this->data;
       
$this->data =& $this->data['child'][$tag][count($this->data['child'][$tag])-1];
    }

    function
cdata($parser, $cdata)
    {
       
$this->data['data'] .= $cdata;
    }

    function
tag_close($parser, $tag)
    {
       
$this->data =& $this->datas[count($this->datas)-1];
       
array_pop($this->datas);
    }
}

$xml_parser = new Simple_Parser;
$xml_parser->parse('<foo><bar>test</bar></foo>');

?>
Didier: dlvb ** free * fr
24.12.2006 18:53
Hi !

After parsing the XML and modifying it, I just add a method to rebuild the XML form the internal structure (xmlp->document).
The method xmlp->toXML writes into xmlp->XML attributes. Then, you just have to output it.
I hope it helps.

<?php
class XMLParser {

var
$parser;
var
$filePath;
var
$document;
var
$currTag;
var
$tagStack;
var
$XML;
var
$_tag_to_close = false;
var
$TAG_ATTRIBUT = 'attr';
var
$TAG_DATA = 'data';

function
XMLParser($path) {
   
$this->parser = xml_parser_create();
   
$this->filePath = $path;
   
$this->document = array();
   
$this->currTag =& $this->document;
   
$this->tagStack = array();
   
$this->XML = "";
}

function
parse() {
   
xml_set_object($this->parser, $this);
   
xml_set_character_data_handler($this->parser, 'dataHandler');
   
xml_set_element_handler($this->parser, 'startHandler', 'endHandler');

   if(!(
$fp = fopen($this->filePath, "r"))) {
       die(
"Cannot open XML data file: $this->filePath");
       return
false;
     }

    while(
$data = fread($fp, 4096)) {
        if(!
xml_parse($this->parser, $data, feof($fp))) {
            die(
sprintf("XML error: %s at line %d",
               
xml_error_string(xml_get_error_code($this->parser)),
            
xml_get_current_line_number($this->parser)));
      }
    }

   
fclose($fp);
   
xml_parser_free($this->parser);

    return
true;
}

function
startHandler($parser, $name, $attribs) {
     if(!isset(
$this->currTag[$name]))
         
$this->currTag[$name] = array();

    
$newTag = array();
     if(!empty(
$attribs))
         
$newTag[$this->TAG_ATTRIBUT] = $attribs;
    
array_push($this->currTag[$name], $newTag);

    
$t =& $this->currTag[$name];
    
$this->currTag =& $t[count($t)-1];
    
array_push($this->tagStack, $name);
}

function
dataHandler($parser, $data) {
   
$data = trim($data);

    if(!empty(
$data)) {
      if(isset(
$this->currTag[$this->TAG_DATA]))
           
$this->currTag[$this->TAG_DATA] .= $data;
      else
           
$this->currTag[$this->TAG_DATA] = $data;
    }
}

function
endHandler($parser, $name) {
    
$this->currTag =& $this->document;
    
array_pop($this->tagStack);

     for(
$i = 0; $i < count($this->tagStack); $i++) {
         
$t =& $this->currTag[$this->tagStack[$i]];
         
$this->currTag =& $t[count($t)-1];
     }
}

function
clearOutput () {
   
$this->XML = "";
}

function
openTag ($tag) {
   
$this->XML.="<".strtolower ($tag);
   
$this->_tag_to_close = true;
}

function
closeTag () {
    if (
$this->_tag_to_close) {
       
$this->XML.=">";
       
$this->_tag_to_close = false;
    }
}

function
closingTag ($tag) {
   
$this->XML.="</".strtolower ($tag).">";
}

function
output_attributes ($contenu_fils) {
    foreach (
$contenu_fils[$this->TAG_ATTRIBUT] as $nomAttribut => $valeur) {
       
$this->XML.= " ".strtolower($nomAttribut)."=\"".$valeur."\"";
    }
}

function
addData ($texte) {
// to be completed
   
$ca  = array ("é", "è", "ê", "à");
   
$par = array ("&eacute;", "&egrave;", "&ecirc;", "agrave;");
    return
htmlspecialchars(str_replace ($ca, $par, $texte), ENT_NOQUOTES);
}

function
toXML ($tags="") {
    if (
$tags=="") {
       
$tags = $this->document;
     
$this->clearOutput ();
    }

    foreach (
$tags as $tag => $contenu) {
       
$this->process ($tag, $contenu);
    }
}

function
process ($tag, $contenu) {
    
// Pour tous les TAGs
   
foreach ($contenu as $indice => $contenu_fils) {
        
$this->openTag ($tag);

        
// Pour tous les fils (non attribut et non data)
        
foreach ($contenu_fils as $tagFils => $fils) {
             switch (
$tagFils) {
                 case
$this->TAG_ATTRIBUT:
                        
$this->output_attributes ($contenu_fils);
                       
$this->closeTag ();
                         break;
                 case
$this->TAG_DATA:
                       
$this->closeTag ();
                        
$this->XML.= $this->addData ($contenu_fils [$this->TAG_DATA]);
                         break;
                 default:
                        
$this->closeTag ();
                        
$this->process ($tagFils, $fils);
                         break;
             }
         }

       
$this->closingTag ($tag);
    }
}

}
?>
forquan
29.01.2006 0:45
Here's code that will create an associative array from an xml file.  Keys are the tag data and subarrays are formed from attributes and child tags

<?php
$p
=& new xmlParser();
$p->parse('/*xml file*/');
print_r($p->output);
?>

<?php
class xmlParser{
   var
$xml_obj = null;
   var
$output = array();
   var
$attrs;

   function
xmlParser(){
      
$this->xml_obj = xml_parser_create();
      
xml_set_object($this->xml_obj,$this);
      
xml_set_character_data_handler($this->xml_obj, 'dataHandler');
      
xml_set_element_handler($this->xml_obj, "startHandler", "endHandler");
   }

   function
parse($path){
       if (!(
$fp = fopen($path, "r"))) {
           die(
"Cannot open XML data file: $path");
           return
false;
       }

       while (
$data = fread($fp, 4096)) {
           if (!
xml_parse($this->xml_obj, $data, feof($fp))) {
               die(
sprintf("XML error: %s at line %d",
              
xml_error_string(xml_get_error_code($this->xml_obj)),
              
xml_get_current_line_number($this->xml_obj)));
              
xml_parser_free($this->xml_obj);
           }
       }

       return
true;
   }

   function
startHandler($parser, $name, $attribs){
      
$_content = array();
       if(!empty(
$attribs))
        
$_content['attrs'] = $attribs;
      
array_push($this->output, $_content);
   }

   function
dataHandler($parser, $data){
       if(!empty(
$data) && $data!="\n") {
          
$_output_idx = count($this->output) - 1;
          
$this->output[$_output_idx]['content'] .= $data;
       }
   }

   function
endHandler($parser, $name){
       if(
count($this->output) > 1) {
          
$_data = array_pop($this->output);
          
$_output_idx = count($this->output) - 1;
          
$add = array();
           if (
$_data['attrs'])
               
$add['attrs'] = $_data['attrs'];
           if (
$_data['child'])
               
$add['child'] = $_data['child'];
          
$this->output[$_output_idx]['child'][$_data['content']] = $add;
       }    
   }
}
?>
Greg S
17.11.2005 17:56
If you need utf8_encode support and configure PHP with --disable-all you will have some trouble. Unfortunately the configure options aren't completely documented. If you need utf8 functions and have everything disabled just recompile PHP with --enable-xml and you should be good to go.
compu_global_hyper_mega_net_2 at yahoo dot com
19.09.2004 22:35
The documentation regarding white space was never complete I think.

The XML_OPTION_SKIP_WHITE doesn't appear to do anything.  I want to preserve the newlines in a cdata section.  Setting XML_OPTION_SKIP_WHITE to 0 or false doesn't appear to help.  My character_data_handler is getting called once for each line.  This obviously should be reflected in the documentation as well.  When/how often does the handler get called exactly?  Having to build separate test cases is very time consuming.

Inserting newlines myself in my cdata handler is no good either.  For non actual CDATA sections that cause my handler to get called, long lines are split up in multiple calls.  My handler would not be able to tell the difference whether or not the subsequent calls would be due to the fact that the data is coming from the next line or the fact that some internal buffer is long enough for it to 'flush' out and call the handler.
This behaviour also needs to be properly documented.
odders
19.03.2004 7:36
I wrote a simple xml parser mainly to deal with rss version 2. I found lots of examples on the net, but they were all masive and bloated and hard to manipulate.

Output is sent to an array, which holds arrays containg data for each item.

Obviously, you will have to make modifications to the code to suit your needs, but there isnt a lot of code there, so that shouldnt be a problem.

<?php

   $currentElements
= array();
  
$newsArray = array();

  
readXml("./news.xml");

   echo(
"<pre>");
  
print_r($newsArray);
   echo(
"</pre>");

  
// Reads XML file into formatted html
  
function readXML($xmlFile)
   {

     
$xmlParser = xml_parser_create();

     
xml_parser_set_option($xmlParser, XML_OPTION_CASE_FOLDING, false);
     
xml_set_element_handler($xmlParser, startElement, endElement);
     
xml_set_character_data_handler($xmlParser, characterData);

     
$fp = fopen($xmlFile, "r");

      while(
$data = fread($fp, filesize($xmlFile))){
        
xml_parse($xmlParser, $data, feof($fp));}

     
xml_parser_free($xmlParser);

   }

  
// Sets the current XML element, and pushes itself onto the element hierarchy
  
function startElement($parser, $name, $attrs)
   {

      global
$currentElements, $itemCount;

     
array_push($currentElements, $name);

      if(
$name == "item"){$itemCount += 1;}

   }

  
// Prints XML data; finds highlights and links
  
function characterData($parser, $data)
   {

      global
$currentElements, $newsArray, $itemCount;

     
$currentCount = count($currentElements);
     
$parentElement = $currentElements[$currentCount-2];
     
$thisElement = $currentElements[$currentCount-1];

      if(
$parentElement == "item"){
        
$newsArray[$itemCount-1][$thisElement] = $data;}
      else{
         switch(
$name){
            case
"title":
               break;
            case
"link":
               break;
            case
"description":
               break;
            case
"language":
               break;
            case
"item":
               break;}}

   }

  
// If the XML element has ended, it is poped off the hierarchy
  
function endElement($parser, $name)
   {

      global
$currentElements;

     
$currentCount = count($currentElements);
      if(
$currentElements[$currentCount-1] == $name){
        
array_pop($currentElements);}

   }

?>
software at serv-a-com dot com
17.02.2003 18:10
2. Pre Parser Strings and New Line Delimited Data
One important thing to note at this point is that the xml_parse function requires a string variable. You can manipulate the content of any string variable easily as we all know.

A better approach to removing newlines than:

<?php
while ($data = fread($fp, 4096)) {
$data = preg_replace("/\n|\r/","",$data); //flarp
if (!xml_parse($xml_parser, $data, feof($fp))) {...
?>

Above works across all 3 line-delimited text files  (\n, \r, \r\n). But this could potentially (or will most likely) damage or scramble data contained in for example CDATA areas. As far as I am concerned end of line characters should not be used _within_ XML tags. What seems to be the ultimate solution is to pre-parse the loaded data this would require checking the position within the XML document and adding or subtracting (using a in-between fread temporary variable) data based on conditions like: "Is within tag", "Is within CDATA" etc. before fedding it to the parser. This of course opens up a new can of worms (as in parse data for the parser...). (above procedure would take place between fread and xml_parser calls this method would be compatible with the general usage examples on top of the page)

3. The Answer to parsing arbitrary XML and Preprocessor Revisited
You can't just feed any XML document to the parser you constructed and assuming that it will work! You have to know what kind of methods for storing data are used, for example is there a end of line delimited data in the  file ?, Are there any carriage returns in the tags etc... XML files come formatted in different ways some are just a one long string of characters with out any end of line markers others have newlines, carriage returns or both (Microsloth Windows). May or may not contain space and other whitespace between tags. For this reason it is important to what I call Normalize the data before feeding it to the parser. You can perform this with regular expressions or plain old str_replace and concatenation. In many cases this can be done to the file it self sometimes to string data on the fly( as shown in the example above). But I feel it is important to normalize the data before even calling the function to call xml_parse. If you have the ability to access all data before that call you can convert it to what you fell the data should have been in the first place and omit many surprises and expensive regular expression substitution (in a tight spot) while fread'ing the data.
software at serv-a-com dot com
17.02.2003 18:09
My previous XML post (software at serv-a-com dot com/22-Jan-2003 03:08) resulted in some of the visitors e-mailg me on the carriage return stripping issue with questions. I'll try to make the following mumble as brief and easy to understand as possible.

1. Overview of the 4096 fragmentation issue
As you know the following freads the file 4096 bytes at a time (that is 4KB) this is perhaps ok for testing expat and figuring out how things work, but it it rather dangerous in the production environment. Data may not be fully understandable due to fread fragmentation and improperly formatted due to numerous sources(formats) of data contained within (i.e. end of line delimited CDATA).

<?php
while ($data = fread($fp, 4096)) {
  if (!
xml_parse($xml_parser, $data, feof($fp))) {
   
// ...
 
}
}
?>

Sometimes to save time one may want to load it all up into a one big variable and leave all the worries to expat. I think anything under 500 KB is ok (as long as nobody knows about it). Some may argue that larger variables are acceptable or even necessary because of the magic that take place while parsing using xml_parse. Our XML parser(expat) works and can be successfully implemented only when we know what type of XML data we are dealing with, it's average size and structure of general layout and data contained within tags. For example if the tags are followed by a line delimiter like a new line we can read it with fgets in and with minimal effort make sure that no data will be sent to the function that does not end with a end tag. But this require a fair knowledge of the file's preference for storing XML data and tags (and a bit of code between reading data and xml_parse'ing it).
software at serv-a-com dot com
22.01.2003 23:08
use:

<?php
while ($data = str_replace("\n","",fread($fp, 4096))){
 
// ...
}
?>

instead of:

<?php
while ($data = fread($fp, 4096)) {
 
// ...
}
?>
It will save you a headache.
guy at bhaktiandvedanta dot com
27.09.2002 21:01
For a simple XML parser you can use this function. It doesn't require any extensions to run.

<?php
// Extracts content from XML tag

function GetElementByName ($xml, $start, $end) {

    global
$pos;
   
$startpos = strpos($xml, $start);
    if (
$startpos === false) {
        return
false;
    }
   
$endpos = strpos($xml, $end);
   
$endpos = $endpos+strlen($end);   
   
$pos = $endpos;
   
$endpos = $endpos-$startpos;
   
$endpos = $endpos - strlen($end);
   
$tag = substr ($xml, $startpos, $endpos);
   
$tag = substr ($tag, strlen($start));

    return
$tag;

}

// Open and read xml file. You can replace this with your xml data.

$file = "data.xml";
$pos = 0;
$Nodes = array();

if (!(
$fp = fopen($file, "r"))) {
    die(
"could not open XML input");
}
while (
$getline = fread($fp, 4096)) {
   
$data = $data . $getline;
}

$count = 0;
$pos = 0;

// Goes throw XML file and creates an array of all <XML_TAG> tags.
while ($node = GetElementByName($data, "<XML_TAG>", "</XML_TAG>")) {
   
$Nodes[$count] = $node;
   
$count++;
   
$data = substr($data, $pos);
}

// Gets infomation from tag siblings.
for ($i=0; $i<$count; $i++) {
$code = GetElementByName($Nodes[$i], "<Code>", "</Code>");
$desc = GetElementByName($Nodes[$i], "<Description>", "</Description>");
$price = GetElementByName($Nodes[$i], "<BasePrice>", "</BasePrice>");
}
?>

Hope this helps! :)
Guy Laor
dmarsh dot NO dot SPAM dot PLEASE at spscc dot ctc dot edu
18.09.2002 21:27
Some reference code I am working on as "XML Library" of which I am folding it info an object. Notice the use of the DEFINE:

Mainly Example 1 and parts of 2 & 3 re-written as an object:
--- MyXMLWalk.lib.php ---
<?php

if (!defined("PHPXMLWalk")) {
define("PHPXMLWalk",TRUE);

class
XMLWalk {
 var
$p; //short for xml parser;
 
var $e; //short for element stack/array

 
function prl($x,$i=0) {
   
ob_start();
   
print_r($x);
   
$buf=ob_get_contents();
   
ob_end_clean();
    return
join("\n".str_repeat(" ",$i),split("\n",$buf));
  }

 function
XMLWalk() {
 
$this->p = xml_parser_create();
 
$this->e = array();
 
xml_parser_set_option($this->p, XML_OPTION_CASE_FOLDING, true);
 
xml_set_element_handler($this->p, array(&$this, "startElement"), array(&$this, "endElement"));
 
xml_set_character_data_handler($this->p, array(&$this, "dataElement"));
 
register_shutdown_function(array(&$this, "free")); // make a destructor
 
}

  function
startElement($parser, $name, $attrs) {
    if (
count($attrs)>=1) {
     
$x = $this->prl($attrs, $this->e[$parser]+6);
    } else {
     
$x = "";
    }

    print
str_repeat(" ",$this->e[$parser]+0). "$name $x\n";
   
$this->e[$parser]++;
   
$this->e[$parser]++;
  }

  function
dataElement($parser, $data) {
    print
str_repeat(" ",$this->e[$parser]+0). htmlspecialchars($data, ENT_QUOTES) ."\n";
  }

  function
endElement($parser, $name) {
   
$this->e[$parser]--;
   
$this->e[$parser]--;
  }
  function
parse($data, $fp) {
    if (!
xml_parse($this->p, $data, feof($fp))) {
        die(
sprintf("XML error: %s at line %d",
                   
xml_error_string(xml_get_error_code($this->p)),
                   
xml_get_current_line_number($this->p)));
    }
  }

  function
free() {
   
xml_parser_free($this->p);
  }

}
// end of class

} // end of define

?>

--- end of file ---

Calling code:
<?php

...

require(
"MyXMLWalk.lib.php");

$file = "x.xml";

$xme = new XMLWalk;

if (!(
$fp = fopen($file, "r"))) {
    die(
"could not open XML input");
}

while (
$data = fread($fp, 4096)) {
 
$xme->parse($data, $fp);
}

...
?>
jon at gettys dot org
14.08.2002 22:59
[Editor's note: see also xml_parse_into_struct().]

Very simple routine to convert an XML file into a PHP structure. $obj->xml contains the resulting PHP structure. I would be interested if someone could suggest a cleaner method than the evals I am using.

<?php
$filename
= 'sample.xml';
$obj->tree = '$obj->xml';
$obj->xml = '';

function
startElement($parser, $name, $attrs) {
    global
$obj;
   
   
// If var already defined, make array
   
eval('$test=isset('.$obj->tree.'->'.$name.');');
    if (
$test) {
      eval(
'$tmp='.$obj->tree.'->'.$name.';');
      eval(
'$arr=is_array('.$obj->tree.'->'.$name.');');
      if (!
$arr) {
        eval(
'unset('.$obj->tree.'->'.$name.');');
        eval(
$obj->tree.'->'.$name.'[0]=$tmp;');
       
$cnt = 1;
      }
      else {
        eval(
'$cnt=count('.$obj->tree.'->'.$name.');');
      }
     
     
$obj->tree .= '->'.$name."[$cnt]";
    }
    else {
     
$obj->tree .= '->'.$name;
    }
    if (
count($attrs)) {
        eval(
$obj->tree.'->attr=$attrs;');
    }
}

function
endElement($parser, $name) {
    global
$obj;
   
// Strip off last ->
   
for($a=strlen($obj->tree);$a>0;$a--) {
        if (
substr($obj->tree, $a, 2) == '->') {
           
$obj->tree = substr($obj->tree, 0, $a);
            break;
        }
    }
}

function
characterData($parser, $data) {
    global
$obj;

    eval(
$obj->tree.'->data=\''.$data.'\';');
}

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

while (
$data = fread($fp, 4096)) {
    if (!
xml_parse($xml_parser, $data, feof($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);
print_r($obj->xml);
return
0;

?>
danielc at analysisandsolutions dot com
15.04.2002 23:23
I put up a good, simple, real world example of how to parse XML documents. While the sample grabs stock quotes off of the web, you can tweak it to do whatever you need.

http://www.analysisandsolutions.com/code/phpxml.htm
jason at NOSPAM_projectexpanse_NOSPAM dot com
27.02.2002 1:11
For newbies wanting a good tutorial on how to actually get started and where to go from this listing of functions, then visit:
http://www.wirelessdevnet.com/channels/wap/features/xmlcast_php.html

It shows an excellent example of how to read the XML data into a class file so you can actually process it, not just display it all pretty-like, like many tutorials on PHP/XML seem to be doing.
hans dot schneider at bbdo-interone dot de
24.01.2002 17:43
I had to TRIM the data when I passed one large String containig a wellformed XML-File to xml_parse. The String was read by CURL, which aparently put a BLANK at the end of the String. This BLANK produced a "XML not wellformed"-Error in xml_parse!
sam at cwa dot co dot nz
28.09.2000 16:39
I've discovered some unusual behaviour in this API when ampersand entities are parsed in cdata; for some reason the parser breaks up the section around the entities, and calls the handler repeated times for each of the sections. If you don't allow for this oddity and you are trying to put the cdata into a variable, only the last part will be stored.

You can get around this with a line like:

$foo .= $cdata;

If the handler is called several times from the same tag, it will append them, rather than rewriting the variable each time. If the entire cdata section is returned, it doesn't matter.

May happen for other entities, but I haven't investigated.

Took me a while to figure out what was happening; hope this saves someone else the trouble.
Daniel dot Rendall at btinternet dot com
7.07.1999 19:21
When using the XML parser, make sure you're not using the magic quotes option (e.g. use set_magic_quotes_runtime(0) if it's not the compiled default), otherwise you'll get 'not well-formed' errors when dealing with tags with attributes set in them.



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