Costanti predefinite
To take care of proper error checking, one must use try-catch blocks:
<?php
try {
$sxe = new SimpleXMLElement($xmlstring);
} catch (Exception $e) {
echo "bad xml";
}
?>
To get rid of warnings, use @ in front of new:
<?php
try {
$sxe = @new SimpleXMLElement($xmlstring);
} catch (Exception $e) {
echo "bad xml";
}
?>
Esempi
Many examples in this reference require an XML string. Instead of repeating this string in every example, we put it into a file which we include in each example. This included file is shown in the following example section. Alternatively, you could create an XML document and read it with simplexml_load_file().
Example #1 Include file example.php with XML string
<?php
$xmlstr = <<<XML
<?xml version='1.0' standalone='yes'?>
<movies>
<movie>
<title>PHP: Behind the Parser</title>
<characters>
<character>
<name>Ms. Coder</name>
<actor>Onlivia Actora</actor>
</character>
<character>
<name>Mr. Coder</name>
<actor>El ActÓr</actor>
</character>
</characters>
<plot>
So, this language. It's like, a programming language. Or is it a
scripting language? All is revealed in this thrilling horror spoof
of a documentary.
</plot>
<great-lines>
<line>PHP solves all my web problems</line>
</great-lines>
<rating type="thumbs">7</rating>
<rating type="stars">5</rating>
</movie>
</movies>
XML;
?>
The simplicity of SimpleXML appears most clearly when one extracts a string or number from a basic XML document.
Example #2 Getting <plot>
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
echo $xml->movie[0]->plot; // "So this language. It's like..."
?>
Accessing elements within an XML document that contain characters not permitted under PHP's naming convention (e.g. the hyphen) can be accomplished by encapsulating the element name within braces and the apostrophe.
Example #3 Getting <line>
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
echo $xml->movie->{'great-lines'}->line; // "PHP solves all my web problems"
?>
Example #4 Accessing non-unique elements in SimpleXML
When multiple instances of an element exist as children of a single parent element, normal iteration techniques apply.
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
/* For each <movie> node, we echo a separate <plot>. */
foreach ($xml->movie as $movie) {
echo $movie->plot, '<br />';
}
?>
Example #5 Using attributes
So far, we have only covered the work of reading element names and their values. SimpleXML can also access element attributes. Access attributes of an element just as you would elements of an array.
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
/* Access the <rating> nodes of the first movie.
* Output the rating scale, too. */
foreach ($xml->movie[0]->rating as $rating) {
switch((string) $rating['type']) { // Get attributes as element indices
case 'thumbs':
echo $rating, ' thumbs up';
break;
case 'stars':
echo $rating, ' stars';
break;
}
}
?>
Example #6 Comparing Elements and Attributes with Text
To compare an element or attribute with a string or pass it into a function that requires a string, you must cast it to a string using (string). Otherwise, PHP treats the element as an object.
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
if ((string) $xml->movie->title == 'PHP: Behind the Parser') {
print 'My favorite movie.';
}
htmlentities((string) $xml->movie->title);
?>
Example #7 Using XPath
SimpleXML includes built-in XPath support. To find all <character> elements:
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
foreach ($xml->xpath('//character') as $character) {
echo $character->name, 'played by ', $character->actor, '<br />';
}
?>
'//' serves as a wildcard. To specify absolute paths, omit one of the slashes.
Example #8 Setting values
Data in SimpleXML doesn't have to be constant. The object allows for manipulation of all of its elements.
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
$xml->movie[0]->characters->character[0]->name = 'Miss Coder';
echo $xml->asXML();
?>
The above code will output a new XML document, just like the original, except that the new XML will change Ms. Coder to Miss Coder.
Example #9 Adding elements and attributes
Since PHP 5.1.3, SimpleXML has had the ability to easily add children and attributes.
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
$character = $xml->movie[0]->characters->addChild('character');
$character->addChild('name', 'Mr. Parser');
$character->addChild('actor', 'John Doe');
$rating = $xml->movie[0]->addChild('rating', 'PG');
$rating->addAttribute('type', 'mpaa');
echo $xml->asXML();
?>
The above code will output an XML document based on the original but having a new character and rating.
Example #10 DOM Interoperability
PHP has a mechanism to convert XML nodes between SimpleXML and DOM formats. This example shows how one might change a DOM element to SimpleXML.
<?php
$dom = new domDocument;
$dom->loadXML('<books><book><title>blah</title></book></books>');
if (!$dom) {
echo 'Error while parsing the document';
exit;
}
$s = simplexml_import_dom($dom);
echo $s->book[0]->title;
?>
add a note
User Contributed NotesEsempi
Kari P.
15-Aug-2008 11:17
15-Aug-2008 11:17
dipl dot paed dot thomas dot schaefer at web dot de
03-May-2008 06:57
03-May-2008 06:57
<?php
class QXML {
...
protected function _toXML(
$xmlArray,
$elmName='graph',
$elmCloseTag="",
$level=0)
{
$xmlString = "";
if(is_array($xmlArray)){
$strXmlAttributes = "";
$key_xml = "";
$keysXmlArray = array_keys($xmlArray);
$curLevel = $level + 1;
if(in_array(self::attribute,$keysXmlArray)){
if(isset($xmlArray[self::attribute])){
if(is_array($xmlArray[self::attribute])){
foreach($xmlArray[self::attribute]
as $xmlArrayKey => $xmlArrayValue)
{
$strXmlAttributes .= sprintf(' %s="%s"',
$xmlArrayKey,
addslashes($xmlArrayValue));
}
}
}
unset($xmlArray[self::attribute]);
}
if(in_array(self::textNode,$keysXmlArray)){
if(isset($xmlArray[self::textNode])){
if($xmlArray[self::textNode]){
$key_xml = $xmlArray[self::textNode];
}
if(strlen($ky_xml)){
$key_xml = sprintf("<![CDATA[%s]]>",$key_xml);
} else {
$key_xml = "";
}
}
unset($xmlArray[self::textNode]);
}
$keysXmlArray=array_keys($xmlArray);
if($elmCloseTag){
$indent=str_repeat(" ",$level * 5);
$xmlString .="\n".$indent.
"<".$elmCloseTag.$strXmlAttributes.">".
$key_xml;
}
if(is_array($xmlArray) && count($xmlArray)>0
&& count($keysXmlArray)>0)
{
reset($xmlArray);
foreach($keysXmlArray as $key){
$altKey = $altKeyXml = $xmlArray[$key];
$check = false;
foreach(array_keys($altKeyXml) as $j=>$p){
if(is_numeric($j)){
$check=true;
$xmlString.= $this->_toXML(
$altKeyXml[$j],
"",
$key,
$curLevel
);
unset($altKeyXml[$j]);
}
}
if($check){
$altKey = $altKeyXml;
}
if($altKey){
$xmlString .= $this->_toXML($altKey,"",$key,$curLevel);
}
}
}
if($elmCloseTag){
$xmlString.= (count($xmlArray)>0?"\n".$indent:"").
"</".$elmCloseTag.">";
}
}
if($elmName) {
$xmlString = "<?xml version='1.0' encoding='UTF-8'?>\n$xmlString\n";
}
return $xmlString;
}
...
}
?>
Honeymonster
30-Apr-2008 03:52
30-Apr-2008 03:52
@david b
@Fabi W
Why can't you use the ->{} operators?
e.g
$xml->{$node}
I've not tested this, but see no reason why it would not work.
Fabi W
23-Apr-2008 09:34
23-Apr-2008 09:34
@david b's approach of dynamically accessing xml-elements:
You can explode the dynamic var with '->' as seperator and thus build a simple function to get the element
function simplexml_get_node_by_query($sxml_obj, $query)
{
$nodes = explode("->", $query);
$currTree = $sxml_obj;
foreach($nodes as $node)
{
$currTree = $currTree->$node;
}
return $currTree;
}
mike at mike-griffiths dot co dot uk
18-Apr-2008 06:11
18-Apr-2008 06:11
It is important that you select the correct method of loading the XML in depending on the format of your XML file.
If you use the wrong function to load it in you will get some strange errors.
david b
13-Apr-2008 12:04
13-Apr-2008 12:04
Use eval() when using variable variables to access SimpleXML nodes.
e.g.
<?php
include 'example.php';
$xml = new SimpleXMLElement($xmlstr);
$s = 'movie[0]->plot' ;
echo "\n1: OK " . $xml->movie[0]->plot ; // OK
echo "\n2: FAIL " . $xml->$s ; // FAIL
echo "\n3: OK " . eval( "return \$xml->$s ;" ) ; // OK
?>