Using XPath, SOAP, and More with Web Services

In this fourth part of a five-part series on Web Services, you'll learn about SimpleXML objects, SOAP, and more. This article is excerpted from chapter 20 of the book Beginning PHP and Oracle: From Novice to Professional, written by W. Jason Gilmore and Bob Bryla (Apress; ISBN: 1590597702).

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By: Apress Publishing

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August 09, 2010

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Creating XML from a SimpleXML Object

TheasXML()method returns a well-formed XML 1.0 string based on the SimpleXML object. Its prototype follows:

string simplexml_element->asXML()

An example follows:

<?php
$xml = simplexml_load_file("books.xml");
echo htmlspecialchars($xml->asXML());
?>

This example returns the original XML document, except that the newline characters have been removed and the characters have been converted to their corresponding HTML entities.

Learning About a Node’s Children

Often you might be interested in only a particular node’s children. Using thechildren()method, retrieving them becomes a trivial affair. Its prototype follows:

object simplexml_element->children()

Suppose for example that thebooks.xmldocument is modified so that each book includes a cast of characters. The Hemingway book might look like the following:

<book>
     <title>The Sun Also Rises</title>
     <author gender="male">Ernest Hemingway</author>
     <description>The masterpiece that launched Hemingway's career.</description>
     <cast>
        <character>Jake Barnes</character>
        <character>Lady Brett Ashley</character>
        <character>Robert Cohn</character>
        <character>Mike Campbell</character>
    </cast>
</book>

Using thechildren()method, you can easily retrieve the characters:

<?php
    $xml = simplexml_load_file("books.xml");
    foreach($xml->book[2]->cast->children() AS $character) {
        echo "$character<br />";
    }
?>

This example returns the following:

--------------------------------------------
Jake Barnes
Lady Brett Ashley
Robert Cohn
Mike Campbell
--------------------------------------------

Next: Using XPath to Retrieve Node Information >>