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Add wrappers around XMLReader and SimpleXMLElement to improve error handling

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Adrien Loison committed 2015-07-27 00:49:43 -07:00
1 parent be3932af18
commit 1ba10ed2b0
16 files changed
+789 -155
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src/Spout/Reader/XLSX/Helper/SharedStringsHelper.php
+50 -82
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@@ -3,6 +3,9 @@
namespace Box\Spout\Reader\XLSX\Helper;
use Box\Spout\Common\Exception\IOException;
use Box\Spout\Reader\Exception\XMLProcessingException;
use Box\Spout\Reader\Wrapper\SimpleXMLElement;
use Box\Spout\Reader\Wrapper\XMLReader;
use Box\Spout\Reader\XLSX\Helper\SharedStringsCaching\CachingStrategyFactory;
use Box\Spout\Reader\XLSX\Helper\SharedStringsCaching\CachingStrategyInterface;
@@ -74,7 +77,7 @@ class SharedStringsHelper
*/
public function extractSharedStrings()
{
$xmlReader = new \XMLReader();
$xmlReader = new XMLReader();
$sharedStringIndex = 0;
$escaper = new \Box\Spout\Common\Escaper\XLSX();
@@ -83,39 +86,44 @@ class SharedStringsHelper
throw new IOException('Could not open "' . self::SHARED_STRINGS_XML_FILE_PATH . '".');
}
$sharedStringsUniqueCount = $this->getSharedStringsUniqueCount($xmlReader);
$this->cachingStrategy = $this->getBestSharedStringsCachingStrategy($sharedStringsUniqueCount);
try {
$sharedStringsUniqueCount = $this->getSharedStringsUniqueCount($xmlReader);
$this->cachingStrategy = $this->getBestSharedStringsCachingStrategy($sharedStringsUniqueCount);
while ($xmlReader->read() && $xmlReader->name !== 'si') {
// do nothing until a 'si' tag is reached
}
while ($xmlReader->name === 'si') {
$node = $this->getSimpleXmlElementNodeFromXMLReader($xmlReader);
$node->registerXPathNamespace('ns', self::MAIN_NAMESPACE_FOR_SHARED_STRINGS_XML);
// removes nodes that should not be read, like the pronunciation of the Kanji characters
$cleanNode = $this->removeSuperfluousTextNodes($node);
// find all text nodes 't'; there can be multiple if the cell contains formatting
$textNodes = $cleanNode->xpath('//ns:t');
$textValue = '';
foreach ($textNodes as $textNode) {
if ($this->shouldPreserveWhitespace($textNode)) {
$textValue .= $textNode->__toString();
} else {
$textValue .= trim($textNode->__toString());
}
while ($xmlReader->read() && $xmlReader->name !== 'si') {
// do nothing until a 'si' tag is reached
}
$unescapedTextValue = $escaper->unescape($textValue);
$this->cachingStrategy->addStringForIndex($unescapedTextValue, $sharedStringIndex);
while ($xmlReader->name === 'si') {
$node = $this->getSimpleXmlElementNodeFromXMLReader($xmlReader);
$node->registerXPathNamespace('ns', self::MAIN_NAMESPACE_FOR_SHARED_STRINGS_XML);
$sharedStringIndex++;
// removes nodes that should not be read, like the pronunciation of the Kanji characters
$cleanNode = $this->removeSuperfluousTextNodes($node);
// jump to the next 'si' tag
$xmlReader->next('si');
// find all text nodes 't'; there can be multiple if the cell contains formatting
$textNodes = $cleanNode->xpath('//ns:t');
$textValue = '';
foreach ($textNodes as $textNode) {
if ($this->shouldPreserveWhitespace($textNode)) {
$textValue .= $textNode->__toString();
} else {
$textValue .= trim($textNode->__toString());
}
}
$unescapedTextValue = $escaper->unescape($textValue);
$this->cachingStrategy->addStringForIndex($unescapedTextValue, $sharedStringIndex);
$sharedStringIndex++;
// jump to the next 'si' tag
$xmlReader->next('si');
}
} catch (XMLProcessingException $exception) {
throw new IOException("The sharedStrings.xml file is invalid and cannot be read. [{$exception->getMessage()}]");
}
$this->cachingStrategy->closeCache();
@@ -134,33 +142,19 @@ class SharedStringsHelper
/**
* Returns the shared strings unique count, as specified in <sst> tag.
*
* @param \XMLReader $xmlReader XMLReader instance
* @param \Box\Spout\Reader\Wrapper\XMLReader $xmlReader XMLReader instance
* @return int Number of unique shared strings in the sharedStrings.xml file
* @throws \Box\Spout\Common\Exception\IOException If sharedStrings.xml is invalid and can't be read
*/
protected function getSharedStringsUniqueCount($xmlReader)
{
// Use internal errors to avoid displaying lots of warning messages in case of invalid file
// For instance, if the file is used to perform a "Billion Laughs" or "Quadratic Blowup" attacks
libxml_clear_errors();
libxml_use_internal_errors(true);
$xmlReader->next('sst');
// Iterate over the "sst" elements to get the actual "sst ELEMENT" (skips any DOCTYPE)
while ($xmlReader->name === 'sst' && $xmlReader->nodeType !== \XMLReader::ELEMENT) {
while ($xmlReader->name === 'sst' && $xmlReader->nodeType !== XMLReader::ELEMENT) {
$xmlReader->read();
}
$readError = libxml_get_last_error();
if ($readError !== false) {
$readErrorMessage = trim($readError->message);
throw new IOException("The sharedStrings.xml file is invalid and cannot be read. [{$readErrorMessage}]");
}
// reset the setting to display XML warnings/errors
libxml_use_internal_errors(false);
return intval($xmlReader->getAttribute('uniqueCount'));
}
@@ -180,29 +174,19 @@ class SharedStringsHelper
* Returns a SimpleXMLElement node from the current node in the given XMLReader instance.
* This is to simplify the parsing of the subtree.
*
* @param \XMLReader $xmlReader
* @return \SimpleXMLElement
* @param \Box\Spout\Reader\Wrapper\XMLReader $xmlReader
* @return \Box\Spout\Reader\Wrapper\SimpleXMLElement
* @throws \Box\Spout\Common\Exception\IOException If the current node cannot be read
*/
protected function getSimpleXmlElementNodeFromXMLReader($xmlReader)
{
// Use internal errors to avoid displaying lots of warning messages in case of error found in the XML node.
// For instance, if the file is used to perform a "Billion Laughs" or "Quadratic Blowup" attacks
libxml_clear_errors();
libxml_use_internal_errors(true);
$node = null;
try {
$node = new \SimpleXMLElement($xmlReader->readOuterXml());
} catch (\Exception $exception) {
$error = libxml_get_last_error();
libxml_use_internal_errors(false);
throw new IOException('The sharedStrings.xml file contains unreadable data [' . trim($error->message) . '].');
$node = new SimpleXMLElement($xmlReader->readOuterXml());
} catch (XMLProcessingException $exception) {
throw new IOException("The sharedStrings.xml file contains unreadable data [{$exception->getMessage()}].");
}
libxml_use_internal_errors(false);
return $node;
}
@@ -210,8 +194,8 @@ class SharedStringsHelper
* Removes nodes that should not be read, like the pronunciation of the Kanji characters.
* By keeping them, their text content would be added to the read string.
*
* @param \SimpleXMLElement $parentNode Parent node that may contain nodes to remove
* @return \SimpleXMLElement Cleaned parent node
* @param \Box\Spout\Reader\Wrapper\SimpleXMLElement $parentNode Parent node that may contain nodes to remove
* @return \Box\Spout\Reader\Wrapper\SimpleXMLElement Cleaned parent node
*/
protected function removeSuperfluousTextNodes($parentNode)
{
@@ -221,12 +205,7 @@ class SharedStringsHelper
foreach ($tagsToRemove as $tagToRemove) {
$xpath = '//ns:' . $tagToRemove;
$nodesToRemove = $parentNode->xpath($xpath);
foreach ($nodesToRemove as $nodeToRemove) {
// This is how to remove a node from the XML
unset($nodeToRemove[0]);
}
$parentNode->removeNodesMatchingXPath($xpath);
}
return $parentNode;
@@ -235,24 +214,13 @@ class SharedStringsHelper
/**
* If the text node has the attribute 'xml:space="preserve"', then preserve whitespace.
*
* @param \SimpleXMLElement $textNode The text node element (<t>) whitespace may be preserved
* @param \Box\Spout\Reader\Wrapper\SimpleXMLElement $textNode The text node element (<t>) whitespace may be preserved
* @return bool Whether whitespace should be preserved
*/
protected function shouldPreserveWhitespace($textNode)
{
$shouldPreserveWhitespace = false;
$attributes = $textNode->attributes('xml', true);
if ($attributes) {
foreach ($attributes as $attributeName => $attributeValue) {
if ($attributeName === 'space' && $attributeValue->__toString() === 'preserve') {
$shouldPreserveWhitespace = true;
break;
}
}
}
return $shouldPreserveWhitespace;
$spaceValue = $textNode->getAttribute('space', 'xml');
return ($spaceValue === 'preserve');
}
/**