ZEND PHP 5 Certification STUDY GUIDE

XML and Web Services ” 195
Modifying XML Documents
Prior to PHP 5.1.3, SimpleXML had no means to add elements and attributes to
an XML document. True, it was possible to change the values of attributes and
elements, but the only way to add new children and attributes was to export the
SimpleXMLElement object to DOM, add the elements and attributes using the latter,
and then import document back into SimpleXML. Needless to say, this process was
anything but simple. PHP 5.1.3, however, introduced two new methods to SimpleXML
that now give it the power it needs to create and modify XML documents:
SimpleXMLElement::addChild() and SimpleXMLElement::addAttribute().
The addChild() method accepts three parameters, the first of which is the name
of the new element. The second is an optional value for this element, and the third
is an optional namespace to which the child belongs. Since the addChild() method
returns a SimpleXMLElement object, you may store this object in a variable to which
you can append its own children and attributes. The following example illustrates
this concept:
$book = $library->addChild(’book’);
$book->addAttribute(’isbn’, ’0812550706’);
$book->addChild(’title’, "Ender’s Game");
$book->addChild(’author’, ’Orson Scott Card’);
$book->addChild(’publisher’, ’Tor Science Fiction’);
header(’Content-type: text/xml’);
echo $library->asXML();
This script adds a new “book” element to the $library object, thus creating a new
object that we store in the $book variable so that we can add an attribute and three
children to it. Finally, in order to display the modified XML document, the script calls
the asXML() method of $library SimpleXMLElement. Before doing so, though, it sets a
Content-type header to ensure that the client (a Web browser in this case) knows how
to handle the content.
Called without a parameter, the asXML() method returns an XML string. However
asXML() also accepts a file path as a parameter, which will cause it to save the XML
document to the given path and return a Boolean value to indicate the operation’s
success.
Licensed to 482634 - Amber Barrow (itsadmin@deakin.edu.au)