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[#1] Glen at ITIStudios dot ca [2013-08-15 18:42:22]
Update: concatenate element contents in function cdata()
<?php
class xmlToArrayParser {
public $array = array();
public $parse_error = false;
private $parser;
private $pointer;
public function __construct($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");
$this->parse_error = xml_parse($this->parser, ltrim($xml))? false : true;
}
public function __destruct() { xml_parser_free($this->parser);}
public function get_xml_error() {
if($this->parse_error) {
$errCode = xml_get_error_code ($this->parser);
$thisError = "Error Code [". $errCode ."] \"<strong style='color:red;'>" . xml_error_string($errCode)."</strong>\",
at char ".xml_get_current_column_number($this->parser) . "
on line ".xml_get_current_line_number($this->parser)."";
}else $thisError = $this->parse_error;
return $thisError;
}
private function tag_open($parser, $tag, $attributes) {
$this->convert_to_array($tag, 'attrib');
$idx=$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['attrib'] = $attributes; }
}
private function cdata($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($current['cdata']);}
}
private function convert_to_array($tag, $item) {
if(isset($this->pointer[$tag]) && !is_array($this->pointer[$tag])){
$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;
}
}
?>
[#2] Glen at ITIStudios dot ca [2013-04-05 19:38:45]
Update: corrected isset() in convert_to_array() function
<?php
class xmlToArrayParser {
public $array = array();
public $parse_error = false;
private $parser;
private $pointer;
public function __construct($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");
$this->parse_error = xml_parse($this->parser, ltrim($xml))? false : true;
}
public function __destruct() { xml_parser_free($this->parser);}
public function get_xml_error() {
if($this->parse_error) {
$errCode = xml_get_error_code ($this->parser);
$thisError = "Error Code [". $errCode ."] \"<strong style='color:red;'>" . xml_error_string($errCode)."</strong>\",
at char ".xml_get_current_column_number($this->parser) . "
on line ".xml_get_current_line_number($this->parser)."";
}else $thisError = $this->parse_error;
return $thisError;
}
private function tag_open($parser, $tag, $attributes) {
$this->convert_to_array($tag, 'attrib');
$idx=$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['attrib'] = $attributes; }
}
private function cdata($parser, $cdata) { $this->pointer['cdata'] = trim($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($current['cdata']);}
}
private function convert_to_array($tag, $item) {
if(isset($this->pointer[$tag]) && !is_array($this->pointer[$tag])){
$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;
}
}
?>
[#3] Glen at ITIStudios dot ca [2011-12-02 15:37:18]
<?php
class xmlToArrayParser {
public $array = array();
public $parse_error = false;
private $parser;
private $pointer;
public function __construct($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");
$this->parse_error = xml_parse($this->parser, ltrim($xml))? false : true;
}
public function __destruct() { xml_parser_free($this->parser);}
public function get_xml_error() {
if($this->parse_error) {
$errCode = xml_get_error_code ($this->parser);
$thisError = "Error Code [". $errCode ."] \"<strong style='color:red;'>" . xml_error_string($errCode)."</strong>\",
at char ".xml_get_current_column_number($this->parser) . "
on line ".xml_get_current_line_number($this->parser)."";
}else $thisError = $this->parse_error;
return $thisError;
}
private function tag_open($parser, $tag, $attributes) {
$this->convert_to_array($tag, 'attrib');
$idx=$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['attrib'] = $attributes; }
}
private function cdata($parser, $cdata) { $this->pointer['cdata'] = trim($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($current['cdata']);}
}
private function convert_to_array($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;
}
}
?>
This is supplimental information for the "class xmlToArrayParser".
This is a fully functional error free, extensively tested php class unlike the posts that follow it.
Key phrase: Fully functional, fully tested, error free XML To Array parser.
<?php
?>
[#4] wolfon.AT-DoG.inbox.ru [2008-07-28 15:09:24]
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
[#5] geoff at spacevs dot com [2007-11-07 21:13:30]
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;
?>
[#6] demonpants at gmail dot com [2007-10-22 20:59:04]
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.
[#7] Zvjezdan Patz [2007-09-09 08:22:03]
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($file));
?>
Prints all my xml quite nicely.
[#8] v9 at fakehalo dot us [2007-07-13 20:04:32]
I needed this for work/personal use. Sometimes you'll have a XML string generated as one long string and no line breaks...nusoap in the case of today/work, but there are any other number of possible things that will generate these. Anyways, this simply takes a long XML string and returns an indented/line-breaked version of the string for display/readability.
<?php
function xmlIndent($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)
[#9] geoffers [at] gmail [dot] com [2006-12-30 15:27:20]
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>');
?>
[#10] Didier: dlvb ** free * fr [2006-12-24 09:53:23]
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 ("??", "??", "??", "??");
$par = array ("é", "è", "ê", "agrave;");
return htmlspecialchars(str_replace ($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);
}
}
}
?>
[#11] forquan [2006-01-28 15:45:48]
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();
$p->parse('');
print_r($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;
}
}
}
?>
[#12] Greg S [2005-11-17 08:56:06]
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.
[#13] compu_global_hyper_mega_net_2 at yahoo dot com [2004-09-19 13:35:25]
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.
[#14] odders [2004-03-18 22:36:44]
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);}
}
?>
[#15] software at serv-a-com dot com [2003-01-22 14:08:26]
use:
<?php
while ($data = str_replace("\n","",fread($fp, 4096))){
// ...
}
?>
instead of:
<?php
while ($data = fread($fp, 4096)) {
// ...
}
?>
[UPDATE 17-FEB-2003: This post] 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).
It will save you a headache.
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.
[#16] guy at bhaktiandvedanta dot com [2002-09-27 12:01:08]
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
[#17] dmarsh dot NO dot SPAM dot PLEASE at spscc dot ctc dot edu [2002-09-18 12:27:19]
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);
}
...
?>
[#18] jon at gettys dot org [2002-08-14 13:59:13]
[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;
?>
[#19] hans dot schneider at bbdo-interone dot de [2002-01-24 08:43:44]
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!
[#20] sam at cwa dot co dot nz [2000-09-28 07:39:06]
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.
[#21] Daniel dot Rendall at btinternet dot com [1999-07-07 10:21:35]
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.