<?xml version="1.0" encoding="utf-8"?>

<chapter xml:id="simplexml.examples" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">

&reftitle.examples;

<section xml:id="simplexml.examples-basic">

<title>Basic SimpleXML usage</title>

<para>

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 <function>simplexml_load_file</function>.

</para>

<para>

<example>

<title>Include file examples/simplexml-data.php with XML string</title>

<programlisting role="php" xml:id="simplexml.examples.movie">

</programlisting>

</example>

</para>

<para>

The simplicity of SimpleXML appears most clearly when one extracts

a string or number from a basic XML document.

<example>

<title>Getting <literal>&lt;plot&gt;</literal></title>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

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>

<title>Getting <literal>&lt;line&gt;</literal></title>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>Accessing non-unique elements in SimpleXML</title>

<simpara>

When multiple instances of an element exist as children of

a single parent element, normal iteration techniques apply.

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<note>

<para>

Properties (<literal>$movies->movie</literal> in previous example) are not

arrays. They are <link linkend="class.iterator">iterable</link> and

<link linkend="class.arrayaccess">accessible</link> objects.

</para>

</note>

<para>

<example>

<title>Using attributes</title>

<simpara>

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 <type>array</type>.

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>Comparing Elements and Attributes with Text</title>

<simpara>

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

<literal>(string)</literal>. Otherwise, PHP treats the element as an object.

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>Comparing Two Elements</title>

<simpara>

Two SimpleXMLElements are considered different even if they point to the

same element.

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>Using XPath</title>

<simpara>

SimpleXML includes built-in <acronym>XPath</acronym> support.

To find all <literal>&lt;character&gt;</literal> elements.

</simpara>

<simpara>

'<literal>//</literal>' serves as a wildcard. To specify absolute

paths, omit one of the slashes:

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>Setting values</title>

<simpara>

Data in SimpleXML doesn't have to be constant. The object allows

for manipulation of all of its elements.

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>Adding elements and attributes</title>

<simpara>

SimpleXML has had the ability to easily add children and

attributes.

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>DOM Interoperability</title>

<simpara>

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.

</simpara>

<programlisting role="php">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<para>

<example>

<title>Working with namespaces</title>

<programlisting role="php">

</programlisting>

</example>

</para>

</section>

<section xml:id="simplexml.examples-errors">

<title>Dealing with XML errors</title>

<para>

Dealing with XML errors when loading documents is a very simple task.

Using the <link linkend="book.libxml">libxml</link> functionality it is

possible to suppress all XML errors when loading the document and then

iterate over the errors.

</para>

<para>

The <classname>LibXMLError</classname> object, returned by

<function>libxml_get_errors</function>, contains several properties

including the <link linkend="libxmlerror.props.message">message</link>,

<link linkend="libxmlerror.props.line">line</link> and

<link linkend="libxmlerror.props.column">column</link> (position) of the

error.

</para>

<para>

<example>

<title>Loading broken XML string</title>

<programlisting role="php" xml:id="simplexml.examples.error">

</programlisting>

&example.outputs;

<screen>

</screen>

</example>

</para>

<section role="seealso"><!-- {{{ -->

&reftitle.seealso;

<para>

<simplelist>

<member><function>libxml_use_internal_errors</function></member>

<member><function>libxml_get_errors</function></member>

<member><xref linkend="class.libxmlerror" /></member>

</simplelist>

</para>

</section>

</section>

</chapter>