From df6855e88b2ca3ccdf23eb5306f1e74c63df56fa Mon Sep 17 00:00:00 2001
From: Mike Ryan <mikeryan@virtuoso-performance.com>
Date: Thu, 19 May 2016 14:24:41 -0500
Subject: [PATCH] Issue #2729581 by mikeryan: Bring XML parser in from
migrate_source_xml
---
src/Plugin/migrate_plus/data_parser/Xml.php | 341 ++++++++++++++++++++
1 file changed, 341 insertions(+)
create mode 100644 src/Plugin/migrate_plus/data_parser/Xml.php
diff --git a/src/Plugin/migrate_plus/data_parser/Xml.php b/src/Plugin/migrate_plus/data_parser/Xml.php
new file mode 100644
index 00000000..65f1bab1
--- /dev/null
+++ b/src/Plugin/migrate_plus/data_parser/Xml.php
@@ -0,0 +1,341 @@
+<?php
+
+namespace Drupal\migrate_plus\Plugin\migrate_plus\data_parser;
+
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\migrate\MigrateException;
+use Drupal\migrate_plus\DataParserPluginBase;
+
+/**
+ * Obtain XML data for migration.
+ *
+ * @DataParser(
+ * id = "xml",
+ * title = @Translation("XML")
+ * )
+ */
+class Xml extends DataParserPluginBase implements ContainerFactoryPluginInterface {
+
+ /**
+ * The XMLReader we are encapsulating.
+ *
+ * @var \XMLReader
+ */
+ protected $reader;
+
+ /**
+ * Array of the element names from the query.
+ *
+ * 0-based from the first (root) element. For example, '//file/article' would
+ * be stored as [0 => 'file', 1 => 'article'].
+ *
+ * @var array
+ */
+ protected $elementsToMatch = [];
+
+ /**
+ * An optional xpath predicate.
+ *
+ * Restricts the matching elements based on values in their children. Parsed
+ * from the element query at construct time.
+ *
+ * @var string
+ */
+ protected $xpathPredicate = NULL;
+
+ /**
+ * Array representing the path to the current element as we traverse the XML.
+ *
+ * For example, if in an XML string like '<file><article>...</article></file>'
+ * we are positioned within the article element, currentPath will be
+ * [0 => 'file', 1 => 'article'].
+ *
+ * @var array
+ */
+ protected $currentPath = [];
+
+ /**
+ * Retains all elements with a given name to support extraction from parents.
+ *
+ * This is a hack to support field extraction of values in parents
+ * of the 'context node' - ie, if $this->fields() has something like '..\nid'.
+ * Since we are using a streaming xml processor, it is too late to snoop
+ * around parent elements again once we've located an element of interest. So,
+ * grab elements with matching names and their depths, and refer back to it
+ * when building the source row.
+ *
+ * @var array
+ */
+ protected $parentXpathCache = [];
+
+ /**
+ * Hash of the element names that should be captured into $parentXpathCache.
+ *
+ * @var array
+ */
+ protected $parentElementsOfInterest = [];
+
+ /**
+ * Element name matching mode.
+ *
+ * When matching element names, whether to compare to the namespace-prefixed
+ * name, or the local name.
+ *
+ * @var bool
+ */
+ protected $prefixedName = FALSE;
+
+ /**
+ * {@inheritdoc}
+ */
+ public function __construct(array $configuration, $plugin_id, $plugin_definition) {
+ parent::__construct($configuration, $plugin_id, $plugin_definition);
+
+ $this->reader = new \XMLReader();
+
+ // Suppress errors during parsing, so we can pick them up after.
+ libxml_use_internal_errors(TRUE);
+
+ // Parse the element query. First capture group is the element path, second
+ // (if present) is the attribute.
+ preg_match_all('|^/([^\[]+)\[?(.*?)]?$|', $configuration['item_selector'], $matches);
+ $element_path = $matches[1][0];
+ $this->elementsToMatch = explode('/', $element_path);
+ $predicate = $matches[2][0];
+ if ($predicate) {
+ $this->xpathPredicate = $predicate;
+ }
+
+ // If the element path contains any colons, it must be specifying
+ // namespaces, so we need to compare using the prefixed element
+ // name in next().
+ if (strpos($element_path, ':')) {
+ $this->prefixedName = TRUE;
+ }
+
+ foreach ($this->fieldSelectors() as $field_name => $xpath) {
+ if (substr($xpath, 0, 3) === '..\\') {
+ $this->parentElementsOfInterest[] = str_replace('..\\', '', $xpath);
+ }
+ }
+ }
+
+ /**
+ * Builds a \SimpleXmlElement rooted at the iterator's current location.
+ *
+ * The resulting SimpleXmlElement also contains any child nodes of the current
+ * element.
+ *
+ * @return \SimpleXmlElement|false
+ * A \SimpleXmlElement when the document is parseable, or false if a
+ * parsing error occurred.
+ *
+ * @throws MigrateException
+ */
+ protected function getSimpleXml() {
+ $node = $this->reader->expand();
+ if ($node) {
+ // We must associate the DOMNode with a DOMDocument to be able to import
+ // it into SimpleXML. Despite appearances, this is almost twice as fast as
+ // simplexml_load_string($this->readOuterXML());
+ $dom = new \DOMDocument();
+ $node = $dom->importNode($node, TRUE);
+ $dom->appendChild($node);
+ $sxml_elem = simplexml_import_dom($node);
+ $this->registerNamespaces($sxml_elem);
+ return $sxml_elem;
+ }
+ else {
+ foreach (libxml_get_errors() as $error) {
+ $error_string = self::parseLibXmlError($error);
+ throw new MigrateException($error_string);
+ }
+ return FALSE;
+ }
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function rewind() {
+ // Reset our path tracker.
+ $this->currentPath = [];
+ parent::rewind();
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function openSourceUrl($url) {
+ // (Re)open the provided URL.
+ $this->reader->close();
+ return $this->reader->open($url, NULL, \LIBXML_NOWARNING);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function fetchNextRow() {
+ $target_element = NULL;
+
+ // Loop over each node in the XML file, looking for elements at a path
+ // matching the input query string (represented in $this->elementsToMatch).
+ while ($this->reader->read()) {
+ if ($this->reader->nodeType == \XMLReader::ELEMENT) {
+ if ($this->prefixedName) {
+ $this->currentPath[$this->reader->depth] = $this->reader->name;
+ if (array_key_exists($this->reader->name, $this->parentElementsOfInterest)) {
+ $this->parentXpathCache[$this->reader->depth][$this->reader->name][] = $this->getSimpleXml();
+ }
+ }
+ else {
+ $this->currentPath[$this->reader->depth] = $this->reader->localName;
+ if (array_key_exists($this->reader->localName, $this->parentElementsOfInterest)) {
+ $this->parentXpathCache[$this->reader->depth][$this->reader->name][] = $this->getSimpleXml();
+ }
+ }
+ if ($this->currentPath == $this->elementsToMatch) {
+ // We're positioned to the right element path - build the SimpleXML
+ // object to enable proper xpath predicate evaluation.
+ $target_element = $this->getSimpleXml();
+ if ($target_element !== FALSE) {
+ if (empty($this->xpathPredicate) || $this->predicateMatches($target_element)) {
+ break;
+ }
+ }
+ }
+ }
+ elseif ($this->reader->nodeType == \XMLReader::END_ELEMENT) {
+ // Remove this element and any deeper ones from the current path.
+ foreach ($this->currentPath as $depth => $name) {
+ if ($depth >= $this->reader->depth) {
+ unset($this->currentPath[$depth]);
+ }
+ }
+ foreach ($this->parentXpathCache as $depth => $elements) {
+ if ($depth > $this->reader->depth) {
+ unset($this->parentXpathCache[$depth]);
+ }
+ }
+ }
+ }
+
+ // If we've found the desired element, populate the currentItem and
+ // currentId with its data.
+ if ($target_element) {
+ foreach ($this->fieldSelectors() as $field_name => $xpath) {
+ foreach ($target_element->xpath($xpath) as $value) {
+ $this->currentItem[$field_name] = (string) $value;
+ }
+ }
+ }
+ }
+
+ /**
+ * Tests whether the iterator's xpath predicate matches the provided element.
+ *
+ * Has some limitations esp. in that it is easy to write predicates that
+ * reference things outside this SimpleXmlElement's tree, but "simpler"
+ * predicates should work as expected.
+ *
+ * @param \SimpleXMLElement $elem
+ * The element to test.
+ *
+ * @return bool
+ * True if the element matches the predicate, false if not.
+ */
+ protected function predicateMatches(\SimpleXMLElement $elem) {
+ return !empty($elem->xpath('/*[' . $this->xpathPredicate . ']'));
+ }
+
+ /**
+ * Gets an ancestor SimpleXMLElement, if the element name was registered.
+ *
+ * Gets the SimpleXMLElement some number of levels above the iterator
+ * having the given name, but only for element names that this
+ * Xml data parser was told to retain for future reference through the
+ * constructor's $parent_elements_of_interest.
+ *
+ * @param int $levels_up
+ * The number of levels back towards the root of the DOM tree to ascend
+ * before searching for the named element.
+ * @param string $name
+ * The name of the desired element.
+ *
+ * @return \SimpleXMLElement|false
+ * The element matching the level and name requirements, or false if it is
+ * not present or was not retained.
+ */
+ public function getAncestorElements($levels_up, $name) {
+ if ($levels_up > 0) {
+ $levels_up *= -1;
+ }
+ $ancestor_depth = $this->reader->depth + $levels_up + 1;
+ if ($ancestor_depth < 0) {
+ return FALSE;
+ }
+
+ if (array_key_exists($ancestor_depth, $this->parentXpathCache) && array_key_exists($name, $this->parentXpathCache[$ancestor_depth])) {
+ return $this->parentXpathCache[$ancestor_depth][$name];
+ }
+ else {
+ return FALSE;
+ }
+ }
+
+ /**
+ * Registers the iterator's namespaces to a SimpleXMLElement.
+ *
+ * @param \SimpleXMLElement $xml
+ * The element to apply namespace registrations to.
+ */
+ protected function registerNamespaces(\SimpleXMLElement $xml) {
+ if (is_array($this->configuration['namespaces'])) {
+ foreach ($this->configuration['namespaces'] as $prefix => $ns) {
+ $xml->registerXPathNamespace($prefix, $ns);
+ }
+ }
+ }
+
+ /**
+ * Parses a LibXMLError to a error message string.
+ *
+ * @param \LibXMLError $error
+ * Error thrown by the XML.
+ *
+ * @return string
+ * Error message
+ */
+ public static function parseLibXmlError(\LibXMLError $error) {
+ $error_code_name = 'Unknown Error';
+ switch ($error->level) {
+ case LIBXML_ERR_WARNING:
+ $error_code_name = t('Warning');
+ break;
+
+ case LIBXML_ERR_ERROR:
+ $error_code_name = t('Error');
+ break;
+
+ case LIBXML_ERR_FATAL:
+ $error_code_name = t('Fatal Error');
+ break;
+ }
+
+ return t(
+ "@libxmlerrorcodename @libxmlerrorcode: @libxmlerrormessage\n" .
+ "Line: @libxmlerrorline\n" .
+ "Column: @libxmlerrorcolumn\n" .
+ "File: @libxmlerrorfile",
+ [
+ '@libxmlerrorcodename' => $error_code_name,
+ '@libxmlerrorcode' => $error->code,
+ '@libxmlerrormessage' => trim($error->message),
+ '@libxmlerrorline' => $error->line,
+ '@libxmlerrorcolumn' => $error->column,
+ '@libxmlerrorfile' => (($error->file)) ? $error->file : NULL,
+ ]
+ );
+ }
+
+}
--
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