&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 string

    <?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;
    ?>

The simplicity of SimpleXML appears most clearly when one extracts a string or number from a basic XML document.

### Getting `<plot>`

    <?php
    include 'example.php';

    $movies = new SimpleXMLElement($xmlstr);

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

&example.outputs;

       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.

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 `<line>`

    <?php
    include 'example.php';

    $movies = new SimpleXMLElement($xmlstr);

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

&example.outputs;

    PHP solves all my web problems

### Accessing non-unique elements in SimpleXML

When multiple instances of an element exist as children of a single parent element, normal iteration techniques apply.

    <?php
    include 'example.php';

    $movies = new SimpleXMLElement($xmlstr);

    /* For each <character> node, we echo a separate <name>. */
    foreach ($movies->movie->characters->character as $character) {
       echo $character->name, ' played by ', $character->actor, PHP_EOL;
    }

    ?>

&example.outputs;

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

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`.

    <?php
    include 'example.php';

    $movies = new SimpleXMLElement($xmlstr);

    /* Access the <rating> 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;

    7 thumbs up5 stars

### 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.

    <?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);
    ?>

&example.outputs;

    My favorite movie.PHP: Behind the Parser

### Comparing Two Elements

Two SimpleXMLElements are considered different even if they point to the same element.

    <?php
    include 'example.php';

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

&example.outputs;

    bool(false)

### Using XPath

SimpleXML includes built-in XPath support. To find all `<character>` elements:

    <?php
    include 'example.php';

    $movies = new SimpleXMLElement($xmlstr);

    foreach ($movies->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;

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

### Setting values

Data in SimpleXML doesn't have to be constant. The object allows for manipulation of all of its elements.

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

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

    echo $movies->asXML();
    ?>

&example.outputs;

    <?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>

### Adding elements and attributes

SimpleXML has had the ability to easily add children and attributes.

    <?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();
    ?>

&example.outputs;

    <?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>

### 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.

    <?php
    $dom = new DOMDocument;
    $dom->loadXML('<books><book><title>blah</title></book></books>');
    if (!$dom) {
        echo 'Error while parsing the document';
        exit;
    }

    $books = simplexml_import_dom($dom);

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

&example.outputs;

    blah

## 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

    <?php
    libxml_use_internal_errors(true);
    $sxe = simplexml_load_string("<?xml version='1.0'><broken><xml></broken>");
    if ($sxe === false) {
        echo "Failed loading XML\n";
        foreach(libxml_get_errors() as $error) {
            echo "\t", $error->message;
        }
    }
    ?>

&example.outputs;

    Failed loading XML
        Blank needed here
        parsing XML declaration: '?>' 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_errors`
- `libxml_get_errors`
- class.libxmlerror