&reftitle.examples;
Basic SimpleXML usage
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.
Include file example.php with XML stringPHP: Behind the ParserMs. CoderOnlivia ActoraMr. CoderEl ActÓr
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.
PHP solves all my web problems75
XML;
?>
]]>
The simplicity of SimpleXML appears most clearly when one extracts
a string or number from a basic XML document.
Getting <literal><plot></literal>
movie[0]->plot;
?>
]]>
&example.outputs;
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.
Getting <literal><line></literal>
movie->{'great-lines'}->line;
?>
]]>
&example.outputs;
Accessing non-unique elements in SimpleXML
When multiple instances of an element exist as children of
a single parent element, normal iteration techniques apply.
node, we echo a separate . */
foreach ($movies->movie->characters->character as $character) {
echo $character->name, ' played by ', $character->actor, PHP_EOL;
}
?>
]]>
&example.outputs;
Properties ($movies->movie in previous example) are not
arrays. They are iterable and
accessible objects.
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.
nodes of the first movie.
* Output the rating scale, too. */
foreach ($movies->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.outputs;
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.
movie->title == 'PHP: Behind the Parser') {
print 'My favorite movie.';
}
echo htmlentities((string) $movies->movie->title);
?>
]]>
&example.outputs;
Comparing Two Elements
Two SimpleXMLElements are considered different even if they point to the
same element.
]]>
&example.outputs;
Using XPath
SimpleXML includes built-in XPath support.
To find all <character> elements:
xpath('//character') as $character) {
echo $character->name, ' played by ', $character->actor, PHP_EOL;
}
?>
]]>
'//' serves as a wildcard. To specify absolute
paths, omit one of the slashes.
&example.outputs;
Setting values
Data in SimpleXML doesn't have to be constant. The object allows
for manipulation of all of its elements.
movie[0]->characters->character[0]->name = 'Miss Coder';
echo $movies->asXML();
?>
]]>
&example.outputs;
PHP: Behind the ParserMiss CoderOnlivia ActoraMr. CoderEl ActÓr
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.
PHP solves all my web problems75
]]>
Adding elements and attributes
SimpleXML has had the ability to easily add children and
attributes.
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 $movies->asXML();
?>
]]>
&example.outputs;
PHP: Behind the ParserMs. CoderOnlivia ActoraMr. CoderEl ActÓrMr. ParserJohn Doe
So, this language. It's like, a programming language. Or is it a
scripting language? All is revealed in this thrilling horror spoof
of a documentary.
PHP solves all my web problems75PG
]]>
DOM Interoperability
PHP has a mechanism to convert XML nodes between SimpleXML
and DOM formats. This example shows how one might change
a DOM element to SimpleXML.
loadXML('blah');
if (!$dom) {
echo 'Error while parsing the document';
exit;
}
$books = simplexml_import_dom($dom);
echo $books->book[0]->title;
?>
]]>
&example.outputs;
Dealing with XML errors
Dealing with XML errors when loading documents is a very simple task.
Using the libxml functionality it is
possible to suppress all XML errors when loading the document and then
iterate over the errors.
The libXMLError object, returned by
libxml_get_errors, contains several properties
including the message,
line and
column (position) of the
error.
Loading broken XML string");
if ($sxe === false) {
echo "Failed loading XML\n";
foreach(libxml_get_errors() as $error) {
echo "\t", $error->message;
}
}
?>
]]>
&example.outputs;
' expected
Opening and ending tag mismatch: xml line 1 and broken
Premature end of data in tag broken line 1
]]>
&reftitle.seealso;
libxml_use_internal_errorslibxml_get_errors