public function fetch()
{
$this->query = $this->url . '?pid=' . $this->pid . '&noredirect=true&format=unixref&id=doi%3A' . $this->doi;
$request_options = array('method' => 'POST');
$result = drupal_http_request($this->query, $request_options);
if ($result->code != 200) {
drupal_set_message(t('HTTP error: !error when trying to contact crossref.org for XML input', array('!error' => $result->code)), 'error');
return;
}
if (empty($result->data)) {
drupal_set_message(t('Did not get any data from crossref.org'), 'error');
return;
}
$sxml = @simplexml_load_string($result->data);
if ($error = (string) $sxml->doi_record->crossref->error) {
drupal_set_message($error, 'error');
return;
}
$this->nodes = array();
$this->parser = drupal_xml_parser_create($result->data);
// use case-folding so we are sure to find the tag in
xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING, FALSE);
xml_parser_set_option($this->parser, XML_OPTION_SKIP_WHITE, TRUE);
xml_set_object($this->parser, $this);
xml_set_element_handler($this->parser, 'unixref_startElement', 'unixref_endElement');
xml_set_character_data_handler($this->parser, 'unixref_characterData');
if (!xml_parse($this->parser, $result->data)) {
drupal_set_message(sprintf("XML error: %s at line %d", xml_error_string(xml_get_error_code($this->parser)), xml_get_current_line_number($this->parser)), 'error');
}
xml_parser_free($this->parser);
return $this->node;
}
/**
* Parses an OPML file.
*
* Feeds are recognized as <outline> elements with the attributes "text" and
* "xmlurl" set.
*
* @param string $opml
* The complete contents of an OPML document.
*
* @return array
* An array of feeds, each an associative array with a "title" and a "url"
* element, or NULL if the OPML document failed to be parsed. An empty array
* will be returned if the document is valid but contains no feeds, as some
* OPML documents do.
*
* @todo Move this to a parser in https://www.drupal.org/node/1963540.
*/
protected function parseOpml($opml)
{
$feeds = array();
$xml_parser = drupal_xml_parser_create($opml);
if (xml_parse_into_struct($xml_parser, $opml, $values)) {
foreach ($values as $entry) {
if ($entry['tag'] == 'OUTLINE' && isset($entry['attributes'])) {
$item = $entry['attributes'];
if (!empty($item['XMLURL']) && !empty($item['TEXT'])) {
$feeds[] = array('title' => $item['TEXT'], 'url' => $item['XMLURL']);
}
}
}
}
xml_parser_free($xml_parser);
return $feeds;
}