XML Parser Class

Calling the XML Parser Class

class XMLparser

ExpressionEngine has an abstracted XML parser that enables developers to work with XML information more easily than with PHP’s built-in XML functions.

To use the XML parser in your modules, you need to first instantiate the XML Parser Class:

ee()->load->library('xmlparser');

Parsing XML

parse_xml($xml)

This method returns an abstracted object containing all of the tags, attributes, and values from the XML. The string parameter must be valid and well-formed XML. Below is an example of the structures generated by this method.

xml_cache Object
(
    [tag] => emails
    [attributes] =>
    [value] =>
    [children] => Array
    (
        [0] => xml_cache Object
        (
            [tag] => email
            [attributes] =>
            [value] =>
            [children] => Array
            (
                [0] => xml_cache Object
                (
                    [tag] => from
                    [attributes] =>
                    [value] => Samantha
                    [children] =>
                )
                [1] => xml_cache Object
                (
                    [tag] => to
                    [attributes] =>
                    [value] => Gertrude
                    [children] =>
                )
                [2] => xml_cache Object
                (
                    [tag] => subject
                    [attributes] =>
                    [value] => You coming to the party?
                    [children] =>
                )
                [3] => xml_cache Object
                (
                    [tag] => message
                    [attributes] => Array
                    (
                        [type] => urgent
                    )
                    [value] => It starts at 9pm.  Don't forget to bring the gruyère!
                    [children] =>
                )
            )
        )
    )
)

With this structure, each tag as an array of objects for each child. In addition to the children array, there are three other variables for each tag object.

Converting Delimited Text to XML

delimited_to_xml($params[, $reduce_null = FALSE])

Takes delimited data and returns XML. Returns FALSE if unable to create XML, and uses the XML class $errors array to log errors encountered. You should always check the $errors array before using the returned XML.

Example:

$data = "Samantha|Gertrude|You coming to the party?|It starts at 9pm.  Don't forget to bring the gruyère!
Inigo|Westley|I know something you don't know.|I am not left-handed!";

$params = array(
    'data'      => $data,
    'structure' => array("from", "to", "subject", "message"),
    'delimiter' => "|",
    'root'      => "emails",
    'element'   => "email"
);

$xml = ee()->xmlparser->delimited_to_xml($params);

Result:

<emails>
    <email>
        <from>Samantha</from>
        <to>Gertrude</to>
        <subject>You coming to the party?</subject>
        <message>It starts at 9pm.  Don't forget to bring the gruyère!</message>
    </email>
    <email>
        <from>Inigo</from>
        <to>Westley</to>
        <subject>I know something you don't know.</subject>
        <message>I am not left-handed!</message>
    </email>
</emails>

Checking for Errors

$errors

You should always check for the presence of errors before using the returned XML. This will allow you to tell which records were skipped and unable to be used in the XML. XMLparser::delimited_to_xml will only return FALSE on fatal errors, as in some cases it may be acceptable to ignore the errors.

if ( ! empty(ee()->xmlparser->errors))
{
    echo "Could not convert to XML:<br /><br />";

    foreach (ee()->xmlparser->errors as $error)
    {
        echo "{$error}<br />";
        exit;
    }
}

You can also take advantage of ExpressionEngine’s error display methods to generate a more UI consistent error page.

if ( ! empty(ee()->xmlparser->errors))
{
  // frontend
  ee()->output->show_user_error('general', ee()->xmlparser->errors);

  // control panel
  show_error(ee()->xmlparser->errors);
}

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