PHP: Temel SimpleXML kullanımı

Temel SimpleXML kullanımı

Bu eklentideki bir çok örnek bir XML dizge gerektirir. Her örnekte bu dizgeyi tekrar tekrar yazmak yerine her örnekte içerilmek üzere bir dosyaya koyduk. Bu dosyanın içeriği aşağıda verilmiştir. İsterseniz kendi XML belgenizi oluşturup simplexml_load_file() işleviyle de okutabilirsiniz.

Örnek 1 - XML dizge olarak içerilecek example.php dosyası

<?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 Act&#211;r</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;
?>

Basit XML eklentisinin basitleştiriciliği, en açık haliyle basit bir XML belgeden bir sayı veya dizgeyi çıkarırken görülür.

Örnek 2 - <plot> içeriğinin eldesi

<?php
include 'example.php';

$movies = new SimpleXMLElement($xmlstr);

echo $movies->movie[0]->plot;
?>

Yukarıdaki örneğin çıktısı:


   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.

Bir XML belgedeki elemanlara erişirken, PHP isimlendirme kurallarına uymayan (örneğin, tire içeren) eleman isimleri tek tırnak ve kaşlı ayraçlarla sarmalanarak belirtilebilir.

Örnek 3 - <line> içeriğinin eldesi

<?php
include 'example.php';

$xml = new SimpleXMLElement($xmlstr);

echo $movies->movie->{'great-lines'}->line;
?>

Yukarıdaki örneğin çıktısı:

PHP solves all my web problems

Örnek 4 - Bir elemanın birden fazla örneğine erişim

Bir ebeveyn elemanın aynı isimdeki birden fazla çocuğunun içeriğini elde etmek için normal yineleme teknikleri kullanılır.

<?php
include 'example.php';

$movies = new SimpleXMLElement($xmlstr);

/* Her <character> düğümündeki <name> içeriğini çıkaralım */
foreach ($movies->movie->characters->character as $character) {
   echo $character->name, ' played by ', $character->actor, PHP_EOL;
}

?>

Yukarıdaki örneğin çıktısı:

Ms. Coder played by Onlivia Actora
Mr. Coder played by El ActÓr

Bilginize:
Özellikler (önceki örnekteki $movies->movie) dizi değildir. Yinelenebilir ve erişilebilir nesnelerdir.

Örnek 5 - Özniteliklerin kullanımı

Şimdiye kadar hep eleman isimleri ve içerikleri ile çalıştık. Basit XML eklentisi eleman özniteliklerine de erişir. Eleman özniteliklerine, eleman ismini taşıyan dizinin anahtarları olarak erişebilirsiniz.

<?php
include 'example.php';

$movies = new SimpleXMLElement($xmlstr);

/* İlk <movie> içindeki <rating> düğümlerine erişelim.
 * İstatistiksel sonuçları çıktılayalım. */
foreach ($movies->movie[0]->rating as $rating) {
    switch((string) $rating['type']) { // Öznitelikler birer anahtardır
    case 'thumbs':
        echo $rating, ' onaylı';
        break;
    case 'stars':
        echo $rating, ' yıldızlı';
        break;
    }
}
?>

Yukarıdaki örneğin çıktısı:

7 thumbs up5 stars

Örnek 6 - Elemanları ve öznitelikleri karşılaştırmak

Bir elemanı veya özniteliği bir dizge ile karşılaştırmak veya bir dizge gerektiren bir işleve aktarmak için nesnenin önüne (string) getirerek tür dönüşümü yapmalısınız. Aksi takdirde PHP, elemanı bir nesne olarak ele alır.

<?php
include 'example.php';

$movies = new SimpleXMLElement($xmlstr);

if ((string) $movies->movie->title == 'PHP: Behind the Parser') {
    print 'My favorite movie.';
}

echo htmlentities((string) $movies->movie->title);
?>

Yukarıdaki örneğin çıktısı:

My favorite movie.PHP: Behind the Parser

Örnek 7 - İki elemanı karşılaştırmak

İki SimpleXMLElement nesnesi, aynı elemana ait olsalar bile, farklı nesneler olarak ele alınır.

<?php
include 'example.php';

$movies1 = new SimpleXMLElement($xmlstr);
$movies2 = new SimpleXMLElement($xmlstr);
var_dump($movies1 == $movies2);
?>

Yukarıdaki örneğin çıktısı:

bool(false)

Örnek 8 - XPath kullanımı

Basit XML eklentisinin yerleşik XPath desteği vardar. Tüm <character> elemanlarını bulmak isteyelim:

<?php
include 'example.php';

$movies = new SimpleXMLElement($xmlstr);

foreach ($movies->xpath('//character') as $character) {
    echo $character->name, ' played by ', $character->actor, PHP_EOL;
}
?>

'//character' ifadesindeki '//' bir kısaltma olup, belgedeki tüm character elemanları anlamına gelir (Bakınız: » XML Adresleme Dili (XPath) 1.0 belirtimi).

Yukarıdaki örneğin çıktısı:

Ms. Coder played by Onlivia Actora
Mr. Coder played by El ActÓr

Örnek 9 - Değer atamak

SimpleXMLElement nesnesinin verileri birer sabit değildir. Nesnenin tüm elemanlarında değişiklik yapılabilir.

<?php
include 'example.php';
$movies = new SimpleXMLElement($xmlstr);

$movies->movie[0]->characters->character[0]->name = 'Miss Coder';

echo $movies->asXML();
?>

Yukarıdaki örneğin çıktısı:

<?xml version="1.0" standalone="yes"?>
<movies>
 <movie>
  <title>PHP: Behind the Parser</title>
  <characters>
   <character>
    <name>Miss Coder</name>
    <actor>Onlivia Actora</actor>
   </character>
   <character>
    <name>Mr. Coder</name>
    <actor>El Act&#xD3;r</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>

Örnek 10 - Eleman ve öznitelik eklemek

SimpleXMLElement nesnesine çocuk elemanlar ve öznitelikler kolayca eklenebilmektedir.

<?php
include 'example.php';
$movies = new SimpleXMLElement($xmlstr);

$character = $movies->movie[0]->characters->addChild('character');
$character->addChild('name', 'Mr. Parser');
$character->addChild('actor', 'John Doe');

$rating = $movies->movie[0]->addChild('rating', 'PG');
$rating->addAttribute('type', 'mpaa');

echo $movies->asXML();
?>

Yukarıdaki örneğin çıktısı:

<?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 Act&#xD3;r</actor>
   </character>
  <character><name>Mr. Parser</name><actor>John Doe</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>
 <rating type="mpaa">PG</rating></movie>
</movies>

Örnek 11 - DOM ile çalışabilirlik

PHP, XML düğümlerin Basit XML ve DOM biçemleri arasında dönüşüm yapılabilmeyi sağlayan bir mekanizmaya sahiptir. Bu örnekte bir DOM elemanının bir SimpleXMLElement nesnesine dönüştürülmesi gösterilmiştir.

<?php
$dom = new DOMDocument;
$dom->loadXML('<books><book><title>blah</title></book></books>');
if (!$dom) {
   echo 'Belge çözümlenirken hata oluştu';
   exit;
}

$books = simplexml_import_dom($dom);

echo $books->book[0]->title;
?>

Yukarıdaki örneğin çıktısı:

blah

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User Contributed Notes 9 notes

down

rowan dot collins at gmail dot com ¶

9 years ago

There is a common "trick" often proposed to convert a SimpleXML object to an array, by running it through json_encode() and then json_decode(). I'd like to explain why this is a bad idea.

Most simply, because the whole point of SimpleXML is to be easier to use and more powerful than a plain array. For instance, you can write <?php $foo->bar->baz['bing'] ?> and it means the same thing as <?php $foo->bar[0]->baz[0]['bing'] ?>, regardless of how many bar or baz elements there are in the XML; and if you write <?php (string)$foo->bar[0]->baz[0] ?> you get all the string content of that node - including CDATA sections - regardless of whether it also has child elements or attributes. You also have access to namespace information, the ability to make simple edits to the XML, and even the ability to "import" into a DOM object, for much more powerful manipulation. All of this is lost by turning the object into an array rather than reading understanding the examples on this page.

Additionally, because it is not designed for this purpose, the conversion to JSON and back will actually lose information in some situations. For instance, any elements or attributes in a namespace will simply be discarded, and any text content will be discarded if an element also has children or attributes. Sometimes, this won't matter, but if you get in the habit of converting everything to arrays, it's going to sting you eventually.

Of course, you could write a smarter conversion, which didn't have these limitations, but at that point, you are getting no value out of SimpleXML at all, and should just use the lower level XML Parser functions, or the XMLReader class, to create your structure. You still won't have the extra convenience functionality of SimpleXML, but that's your loss.

down

jishcem at gmail dot com ¶

11 years ago

For me it was easier to use arrays than objects, 

So, I used this code, 

$xml = simplexml_load_file('xml_file.xml');
    
$json_string = json_encode($xml);
    
$result_array = json_decode($json_string, TRUE);

Hope it would help someone

down

Anonymous ¶

7 years ago

If your xml string contains booleans encoded with "0" and "1", you will run into problems when you cast the element directly to bool:

$xmlstr = <<<XML
<?xml version='1.0' standalone='yes'?>
<values>
    <truevalue>1</truevalue>
    <falsevalue>0</falsevalue>
</values>
XML;
$values = new SimpleXMLElement($xmlstr);
$truevalue = (bool)$values->truevalue; // true
$falsevalue = (bool)$values->falsevalue; // also true!!!

Instead you need to cast to string or int first:

$truevalue = (bool)(int)$values->truevalue; // true
$falsevalue = (bool)(int)$values->falsevalue; // false

down

Josef ¶

3 years ago

How to find out if a Node exists:

<?xml version='1.0' standalone='yes'?>
<book>
  <author>Josef</author>
  <isbn></isbn>
</book>

empty($xml->isbn) will be true
isset($xml->isbn) will be true

empty($xml->title) will be true
isset($xml->title) will be false

down

ie dot raymond at gmail dot com ¶

14 years ago

If you need to output valid xml in your response, don't forget to set your header content type to xml in addition to echoing out the result of asXML():



<?php



$xml=simplexml_load_file('...');

...

...xml stuff

...



//output xml in your response:

header('Content-Type: text/xml');

echo $xml->asXML();

?>

down

gkokmdam at zonnet dot nl ¶

13 years ago

A quick tip on xpath queries and default namespaces. It looks like the XML-system behind SimpleXML has the same workings as I believe the XML-system .NET uses: when one needs to address something in the default namespace, one will have to declare the namespace using registerXPathNamespace and then use its prefix to address the otherwise in the default namespace living element.

<?php
$string = <<<XML
<?xml version='1.0'?> 
<document xmlns="http://www.w3.org/2005/Atom">
 <title>Forty What?</title>
 <from>Joe</from>
 <to>Jane</to>
 <body>
  I know that's the answer -- but what's the question?
 </body>
</document>
XML;

$xml = simplexml_load_string($string);
$xml->registerXPathNamespace("def", "http://www.w3.org/2005/Atom");

$nodes = $xml->xpath("//def:document/def:title");

?>

down

kdos ¶

13 years ago

Using stuff like: is_object($xml->module->admin) to check if there actually is a node called "admin", doesn't seem to work as expected, since simplexml always returns an object- in that case an empty one  - even if a particular node does not exist. 
For me good old empty() function seems to work just fine in such cases.

Cheers

down

Max K. ¶

14 years ago

From the README file:

SimpleXML is meant to be an easy way to access XML data.

SimpleXML objects follow four basic rules:

1) properties denote element iterators
2) numeric indices denote elements
3) non numeric indices denote attributes
4) string conversion allows to access TEXT data

When iterating properties then the extension always iterates over
all nodes with that element name. Thus method children() must be 
called to iterate over subnodes. But also doing the following:
foreach ($obj->node_name as $elem) {
  // do something with $elem
}
always results in iteration of 'node_name' elements. So no further 
check is needed to distinguish the number of nodes of that type.

When an elements TEXT data is being accessed through a property
then the result does not include the TEXT data of subelements.

Known issues
============

Due to engine problems it is currently not possible to access
a subelement by index 0: $object->property[0].

down

-1

php at keith tyler dot com ¶

14 years ago

[Editor's Note: The SimpleXMLIterator class, however, does implement these methods.]



While SimpleXMLElement claims to be iterable, it does not seem to implement the standard Iterator interface functions like ::next and ::reset properly. Therefore while foreach() works, functions like next(), current(), or each() don't seem to work as you would expect -- the pointer never seems to move or keeps getting reset.

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