Retrieve XLSX sheets in order of appearance

Instead of relying on the ID, sheets should be retrieved in the order they appear in the file.
Workbook.xml describes the correct order.
This allows the reader to read data in the correct order when sheets have been manually moved after creation.

src/Spout/Reader/XLSX/Helper/SheetHelper.php

@@ -14,18 +14,13 @@ use Box\Spout\Reader\XLSX\Sheet;
 class SheetHelper
 {
     /** Paths of XML files relative to the XLSX file root */
-    const CONTENT_TYPES_XML_FILE_PATH = '[Content_Types].xml';
     const WORKBOOK_XML_RELS_FILE_PATH = 'xl/_rels/workbook.xml.rels';
     const WORKBOOK_XML_FILE_PATH = 'xl/workbook.xml';
 
     /** Namespaces for the XML files */
-    const MAIN_NAMESPACE_FOR_CONTENT_TYPES_XML = 'http://schemas.openxmlformats.org/package/2006/content-types';
     const MAIN_NAMESPACE_FOR_WORKBOOK_XML_RELS = 'http://schemas.openxmlformats.org/package/2006/relationships';
     const MAIN_NAMESPACE_FOR_WORKBOOK_XML = 'http://schemas.openxmlformats.org/spreadsheetml/2006/main';
 
-    /** Value of the Override attribute used in [Content_Types].xml to define sheets */
-    const OVERRIDE_CONTENT_TYPES_ATTRIBUTE = 'application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml';
-
     /** @var string Path of the XLSX file being read */
     protected $filePath;
 
@@ -63,65 +58,51 @@ class SheetHelper
     {
         $sheets = [];
 
-        $contentTypesAsXMLElement = $this->getFileAsXMLElementWithNamespace(
-            self::CONTENT_TYPES_XML_FILE_PATH,
-            self::MAIN_NAMESPACE_FOR_CONTENT_TYPES_XML
-        );
+        // Starting from "workbook.xml" as this file is the source of truth for the sheets order
+        $workbookXMLElement = $this->getWorkbookXMLAsXMLElement();
+        $sheetNodes = $workbookXMLElement->xpath('//ns:sheet');
 
-        // find all nodes defining a sheet
-        $sheetNodes = $contentTypesAsXMLElement->xpath('//ns:Override[@ContentType="' . self::OVERRIDE_CONTENT_TYPES_ATTRIBUTE . '"]');
-        $numSheetNodes = count($sheetNodes);
-
-        for ($i = 0; $i < $numSheetNodes; $i++) {
-            $sheetNode = $sheetNodes[$i];
-            $sheetDataXMLFilePath = $sheetNode->getAttribute('PartName');
-
-            $sheets[] = $this->getSheetFromXML($sheetDataXMLFilePath);
+        foreach ($sheetNodes as $sheetIndex => $sheetNode) {
+            $sheets[] = $this->getSheetFromSheetXMLNode($sheetNode, $sheetIndex);
         }
 
-        // make sure the sheets are sorted by index
-        // (as the sheets are not necessarily in this order in the XML file)
-        usort($sheets, function ($sheet1, $sheet2) {
-            return ($sheet1->getIndex() - $sheet2->getIndex());
-        });
-
         return $sheets;
     }
 
     /**
-     * Returns an instance of a sheet, given the path of its data XML file.
-     * We first look at "xl/_rels/workbook.xml.rels" to find the relationship ID of the sheet.
-     * Then we look at "xl/worbook.xml" to find the sheet entry associated to the found ID.
-     * The entry contains the ID and name of the sheet.
+     * Returns an instance of a sheet, given the XML node describing the sheet - from "workbook.xml".
+     * We can find the XML file path describing the sheet inside "workbook.xml.res", by mapping with the sheet ID
+     * ("r:id" in "workbook.xml", "Id" in "workbook.xml.res").
      *
-     * @param string $sheetDataXMLFilePath Path of the sheet data XML file as in [Content_Types].xml
+     * @param \Box\Spout\Reader\Wrapper\SimpleXMLElement $sheetNode XML Node describing the sheet, as defined in "workbook.xml"
+     * @param int $sheetIndexZeroBased Index of the sheet, based on order of appearance in the workbook (zero-based)
      * @return \Box\Spout\Reader\XLSX\Sheet Sheet instance
      */
-    protected function getSheetFromXML($sheetDataXMLFilePath)
+    protected function getSheetFromSheetXMLNode($sheetNode, $sheetIndexZeroBased)
     {
-        // In [Content_Types].xml, the path is "/xl/worksheets/sheet1.xml"
-        // In workbook.xml.rels, it is only "worksheets/sheet1.xml"
-        $sheetDataXMLFilePathInWorkbookXMLRels = ltrim($sheetDataXMLFilePath, '/xl/');
-
-        // find the node associated to the given file path
-        $workbookXMLResElement = $this->getWorkbookXMLRelsAsXMLElement();
-        $relationshipNodes = $workbookXMLResElement->xpath('//ns:Relationship[@Target="' . $sheetDataXMLFilePathInWorkbookXMLRels . '"]');
-        $relationshipNode = $relationshipNodes[0];
-
-        $relationshipSheetId = $relationshipNode->getAttribute('Id');
-
-        $workbookXMLElement = $this->getWorkbookXMLAsXMLElement();
-        $sheetNodes = $workbookXMLElement->xpath('//ns:sheet[@r:id="' . $relationshipSheetId . '"]');
-        $sheetNode = $sheetNodes[0];
+        // To retrieve namespaced attributes, some versions of LibXML will accept prefixing the attribute
+        // with the namespace directly (tested on LibXML 2.9.3). For older versions (tested on LibXML 2.7.8),
+        // attributes need to be retrieved without the namespace hint.
+        $sheetId = $sheetNode->getAttribute('r:id');
+        if ($sheetId === null) {
+            $sheetId = $sheetNode->getAttribute('id');
+        }
 
         $escapedSheetName = $sheetNode->getAttribute('name');
-        $sheetIdOneBased = $sheetNode->getAttribute('sheetId');
-        $sheetIndexZeroBased = $sheetIdOneBased - 1;
 
         /** @noinspection PhpUnnecessaryFullyQualifiedNameInspection */
         $escaper = new \Box\Spout\Common\Escaper\XLSX();
         $sheetName = $escaper->unescape($escapedSheetName);
 
+        // find the file path of the sheet, by looking at the "workbook.xml.res" file
+        $workbookXMLResElement = $this->getWorkbookXMLRelsAsXMLElement();
+        $relationshipNodes = $workbookXMLResElement->xpath('//ns:Relationship[@Id="' . $sheetId . '"]');
+        $relationshipNode = $relationshipNodes[0];
+
+        // In workbook.xml.rels, it is only "worksheets/sheet1.xml"
+        // In [Content_Types].xml, the path is "/xl/worksheets/sheet1.xml"
+        $sheetDataXMLFilePath = '/xl/' . $relationshipNode->getAttribute('Target');
+
         return new Sheet($this->filePath, $sheetDataXMLFilePath, $this->sharedStringsHelper, $sheetIndexZeroBased, $sheetName);
     }
 

tests/Spout/Reader/XLSX/ReaderTest.php

@@ -23,7 +23,7 @@ class ReaderTest extends \PHPUnit_Framework_TestCase
     {
         return [
             ['/path/to/fake/file.xlsx'],
-            ['file_with_no_sheets_in_content_types.xlsx'],
+            ['file_with_no_sheets_in_workbook_xml.xlsx'],
             ['file_with_sheet_xml_not_matching_content_types.xlsx'],
             ['file_corrupted.xlsx'],
         ];