Writer Xlsx Use Constants Rather Than Literals for Namespaces (#3110)

When adding support for non-standard namespacing to Reader Xlsx, I changed most (hopefully all) the uses of string literals for the namespaces to class constants instead. Writer Xlsx naturally uses all the same namespaces, but has continued to use string literals. This PR replaces those with the same constants used by Reader Xlsx.

src/PhpSpreadsheet/Reader/Xlsx/Namespaces.php

@@ -18,23 +18,39 @@ class Namespaces
 
     const THEME = 'http://schemas.openxmlformats.org/package/2006/relationships/theme';
 
+    const THEME2 = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/theme';
+
     const COMPATIBILITY = 'http://schemas.openxmlformats.org/markup-compatibility/2006';
 
     const MAIN = 'http://schemas.openxmlformats.org/spreadsheetml/2006/main';
 
+    const RELATIONSHIPS_DRAWING = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/drawing';
+
     const DRAWINGML = 'http://schemas.openxmlformats.org/drawingml/2006/main';
 
     const CHART = 'http://schemas.openxmlformats.org/drawingml/2006/chart';
 
+    const CHART_ALTERNATE = 'http://schemas.microsoft.com/office/drawing/2007/8/2/chart';
+
+    const RELATIONSHIPS_CHART = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/chart';
+
     const SPREADSHEET_DRAWING = 'http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing';
 
     const SCHEMA_OFFICE_DOCUMENT = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships';
 
     const COMMENTS = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/comments';
 
-    //const CUSTOM_PROPERTIES = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/custom-properties';
+    const RELATIONSHIPS_CUSTOM_PROPERTIES = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/custom-properties';
 
-    //const EXTENDED_PROPERTIES = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties';
+    const RELATIONSHIPS_EXTENDED_PROPERTIES = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties';
+
+    const RELATIONSHIPS_CTRLPROP = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/ctrlProp';
+
+    const CUSTOM_PROPERTIES = 'http://schemas.openxmlformats.org/officeDocument/2006/custom-properties';
+
+    const EXTENDED_PROPERTIES = 'http://schemas.openxmlformats.org/officeDocument/2006/extended-properties';
+
+    const PROPERTIES_VTYPES = 'http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes';
 
     const HYPERLINK = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink';
 
@@ -58,13 +74,29 @@ class Namespaces
 
     const VBA = 'http://schemas.microsoft.com/office/2006/relationships/vbaProject';
 
+    const VBA_SIGNATURE = 'http://schemas.microsoft.com/office/2006/relationships/vbaProject';
+
     const DATA_VALIDATIONS1 = 'http://schemas.microsoft.com/office/spreadsheetml/2009/9/main';
 
     const DATA_VALIDATIONS2 = 'http://schemas.microsoft.com/office/excel/2006/main';
 
+    const CONTENT_TYPES = 'http://schemas.openxmlformats.org/package/2006/content-types';
+
+    const RELATIONSHIPS_PRINTER_SETTINGS = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/printerSettings';
+
+    const RELATIONSHIPS_TABLE = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/table';
+
+    const SPREADSHEETML_AC = 'http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac';
+
     const DC_ELEMENTS = 'http://purl.org/dc/elements/1.1/';
 
-    const DC_TERMS = 'http://purl.org/dc/terms';
+    const DC_TERMS = 'http://purl.org/dc/terms/';
+
+    const DC_DCMITYPE = 'http://purl.org/dc/dcmitype/';
+
+    const SCHEMA_INSTANCE = 'http://www.w3.org/2001/XMLSchema-instance';
+
+    const URN_EXCEL = 'urn:schemas-microsoft-com:office:excel';
 
     const URN_MSOFFICE = 'urn:schemas-microsoft-com:office:office';
 

src/PhpSpreadsheet/Writer/Xlsx/Chart.php

@@ -12,6 +12,7 @@ use PhpOffice\PhpSpreadsheet\Chart\PlotArea;
 use PhpOffice\PhpSpreadsheet\Chart\Properties;
 use PhpOffice\PhpSpreadsheet\Chart\Title;
 use PhpOffice\PhpSpreadsheet\Chart\TrendLine;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Writer\Exception as WriterException;
 
@@ -48,9 +49,9 @@ class Chart extends WriterPart
 
         // c:chartSpace
         $objWriter->startElement('c:chartSpace');
-        $objWriter->writeAttribute('xmlns:c', 'http://schemas.openxmlformats.org/drawingml/2006/chart');
+        $objWriter->writeAttribute('xmlns:c', Namespaces::CHART);
-        $objWriter->writeAttribute('xmlns:a', 'http://schemas.openxmlformats.org/drawingml/2006/main');
+        $objWriter->writeAttribute('xmlns:a', Namespaces::DRAWINGML);
-        $objWriter->writeAttribute('xmlns:r', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships');
+        $objWriter->writeAttribute('xmlns:r', Namespaces::SCHEMA_OFFICE_DOCUMENT);
 
         $objWriter->startElement('c:date1904');
         $objWriter->writeAttribute('val', '0');
@@ -1553,11 +1554,11 @@ class Chart extends WriterPart
     private function writeAlternateContent(XMLWriter $objWriter): void
     {
         $objWriter->startElement('mc:AlternateContent');
-        $objWriter->writeAttribute('xmlns:mc', 'http://schemas.openxmlformats.org/markup-compatibility/2006');
+        $objWriter->writeAttribute('xmlns:mc', Namespaces::COMPATIBILITY);
 
         $objWriter->startElement('mc:Choice');
         $objWriter->writeAttribute('Requires', 'c14');
-        $objWriter->writeAttribute('xmlns:c14', 'http://schemas.microsoft.com/office/drawing/2007/8/2/chart');
+        $objWriter->writeAttribute('xmlns:c14', Namespaces::CHART_ALTERNATE);
 
         $objWriter->startElement('c14:style');
         $objWriter->writeAttribute('val', '102');

src/PhpSpreadsheet/Writer/Xlsx/Comments.php

@@ -4,6 +4,7 @@ namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
 use PhpOffice\PhpSpreadsheet\Comment;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 
 class Comments extends WriterPart
@@ -40,7 +41,7 @@ class Comments extends WriterPart
 
         // comments
         $objWriter->startElement('comments');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
+        $objWriter->writeAttribute('xmlns', Namespaces::MAIN);
 
         // Loop through authors
         $objWriter->startElement('authors');
@@ -107,9 +108,9 @@ class Comments extends WriterPart
 
         // xml
         $objWriter->startElement('xml');
-        $objWriter->writeAttribute('xmlns:v', 'urn:schemas-microsoft-com:vml');
+        $objWriter->writeAttribute('xmlns:v', Namespaces::URN_VML);
-        $objWriter->writeAttribute('xmlns:o', 'urn:schemas-microsoft-com:office:office');
+        $objWriter->writeAttribute('xmlns:o', Namespaces::URN_MSOFFICE);
-        $objWriter->writeAttribute('xmlns:x', 'urn:schemas-microsoft-com:office:excel');
+        $objWriter->writeAttribute('xmlns:x', Namespaces::URN_EXCEL);
 
         // o:shapelayout
         $objWriter->startElement('o:shapelayout');

src/PhpSpreadsheet/Writer/Xlsx/ContentTypes.php

@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\File;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
@@ -32,7 +33,7 @@ class ContentTypes extends WriterPart
 
         // Types
         $objWriter->startElement('Types');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/content-types');
+        $objWriter->writeAttribute('xmlns', Namespaces::CONTENT_TYPES);
 
         // Theme
         $this->writeOverrideContentType($objWriter, '/xl/theme/theme1.xml', 'application/vnd.openxmlformats-officedocument.theme+xml');

src/PhpSpreadsheet/Writer/Xlsx/DefinedNames.php

@@ -8,7 +8,7 @@ use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
 use PhpOffice\PhpSpreadsheet\DefinedName;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
-use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet as ActualWorksheet;
 
 class DefinedNames
 {
@@ -98,7 +98,7 @@ class DefinedNames
     /**
      * Write Defined Name for autoFilter.
      */
-    private function writeNamedRangeForAutofilter(Worksheet $worksheet, int $worksheetId = 0): void
+    private function writeNamedRangeForAutofilter(ActualWorksheet $worksheet, int $worksheetId = 0): void
     {
         // NamedRange for autoFilter
         $autoFilterRange = $worksheet->getAutoFilter()->getRange();
@@ -112,7 +112,7 @@ class DefinedNames
             $range = Coordinate::splitRange($autoFilterRange);
             $range = $range[0];
             //    Strip any worksheet ref so we can make the cell ref absolute
-            [, $range[0]] = Worksheet::extractSheetTitle($range[0], true);
+            [, $range[0]] = ActualWorksheet::extractSheetTitle($range[0], true);
 
             $range[0] = Coordinate::absoluteCoordinate($range[0]);
             if (count($range) > 1) {
@@ -129,7 +129,7 @@ class DefinedNames
     /**
      * Write Defined Name for PrintTitles.
      */
-    private function writeNamedRangeForPrintTitles(Worksheet $worksheet, int $worksheetId = 0): void
+    private function writeNamedRangeForPrintTitles(ActualWorksheet $worksheet, int $worksheetId = 0): void
     {
         // NamedRange for PrintTitles
         if ($worksheet->getPageSetup()->isColumnsToRepeatAtLeftSet() || $worksheet->getPageSetup()->isRowsToRepeatAtTopSet()) {
@@ -167,7 +167,7 @@ class DefinedNames
     /**
      * Write Defined Name for PrintTitles.
      */
-    private function writeNamedRangeForPrintArea(Worksheet $worksheet, int $worksheetId = 0): void
+    private function writeNamedRangeForPrintArea(ActualWorksheet $worksheet, int $worksheetId = 0): void
     {
         // NamedRange for PrintArea
         if ($worksheet->getPageSetup()->isPrintAreaSet()) {

src/PhpSpreadsheet/Writer/Xlsx/DocProps.php

@@ -3,6 +3,7 @@
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
 use PhpOffice\PhpSpreadsheet\Document\Properties;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\Date;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
@@ -29,8 +30,8 @@ class DocProps extends WriterPart
 
         // Properties
         $objWriter->startElement('Properties');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/officeDocument/2006/extended-properties');
+        $objWriter->writeAttribute('xmlns', Namespaces::EXTENDED_PROPERTIES);
-        $objWriter->writeAttribute('xmlns:vt', 'http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes');
+        $objWriter->writeAttribute('xmlns:vt', Namespaces::PROPERTIES_VTYPES);
 
         // Application
         $objWriter->writeElement('Application', 'Microsoft Excel');
@@ -124,11 +125,11 @@ class DocProps extends WriterPart
 
         // cp:coreProperties
         $objWriter->startElement('cp:coreProperties');
-        $objWriter->writeAttribute('xmlns:cp', 'http://schemas.openxmlformats.org/package/2006/metadata/core-properties');
+        $objWriter->writeAttribute('xmlns:cp', Namespaces::CORE_PROPERTIES2);
-        $objWriter->writeAttribute('xmlns:dc', 'http://purl.org/dc/elements/1.1/');
+        $objWriter->writeAttribute('xmlns:dc', Namespaces::DC_ELEMENTS);
-        $objWriter->writeAttribute('xmlns:dcterms', 'http://purl.org/dc/terms/');
+        $objWriter->writeAttribute('xmlns:dcterms', Namespaces::DC_TERMS);
-        $objWriter->writeAttribute('xmlns:dcmitype', 'http://purl.org/dc/dcmitype/');
+        $objWriter->writeAttribute('xmlns:dcmitype', Namespaces::DC_DCMITYPE);
-        $objWriter->writeAttribute('xmlns:xsi', 'http://www.w3.org/2001/XMLSchema-instance');
+        $objWriter->writeAttribute('xmlns:xsi', Namespaces::SCHEMA_INSTANCE);
 
         // dc:creator
         $objWriter->writeElement('dc:creator', $spreadsheet->getProperties()->getCreator());
@@ -198,8 +199,8 @@ class DocProps extends WriterPart
 
         // cp:coreProperties
         $objWriter->startElement('Properties');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/officeDocument/2006/custom-properties');
+        $objWriter->writeAttribute('xmlns', Namespaces::CUSTOM_PROPERTIES);
-        $objWriter->writeAttribute('xmlns:vt', 'http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes');
+        $objWriter->writeAttribute('xmlns:vt', Namespaces::PROPERTIES_VTYPES);
 
         foreach ($customPropertyList as $key => $customProperty) {
             $propertyValue = $spreadsheet->getProperties()->getCustomPropertyValue($customProperty);

src/PhpSpreadsheet/Writer/Xlsx/Drawing.php

@@ -3,6 +3,7 @@
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\Drawing as SharedDrawing;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
@@ -34,8 +35,8 @@ class Drawing extends WriterPart
 
         // xdr:wsDr
         $objWriter->startElement('xdr:wsDr');
-        $objWriter->writeAttribute('xmlns:xdr', 'http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing');
+        $objWriter->writeAttribute('xmlns:xdr', Namespaces::SPREADSHEET_DRAWING);
-        $objWriter->writeAttribute('xmlns:a', 'http://schemas.openxmlformats.org/drawingml/2006/main');
+        $objWriter->writeAttribute('xmlns:a', Namespaces::DRAWINGML);
 
         // Loop through images and write drawings
         $i = 1;
@@ -159,10 +160,10 @@ class Drawing extends WriterPart
 
         $objWriter->startElement('a:graphic');
         $objWriter->startElement('a:graphicData');
-        $objWriter->writeAttribute('uri', 'http://schemas.openxmlformats.org/drawingml/2006/chart');
+        $objWriter->writeAttribute('uri', Namespaces::CHART);
         $objWriter->startElement('c:chart');
-        $objWriter->writeAttribute('xmlns:c', 'http://schemas.openxmlformats.org/drawingml/2006/chart');
+        $objWriter->writeAttribute('xmlns:c', Namespaces::CHART);
-        $objWriter->writeAttribute('xmlns:r', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships');
+        $objWriter->writeAttribute('xmlns:r', Namespaces::SCHEMA_OFFICE_DOCUMENT);
         $objWriter->writeAttribute('r:id', 'rId' . $relationId);
         $objWriter->endElement();
         $objWriter->endElement();
@@ -265,7 +266,7 @@ class Drawing extends WriterPart
 
             // a:blip
             $objWriter->startElement('a:blip');
-            $objWriter->writeAttribute('xmlns:r', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships');
+            $objWriter->writeAttribute('xmlns:r', Namespaces::SCHEMA_OFFICE_DOCUMENT);
             $objWriter->writeAttribute('r:embed', 'rId' . $relationId);
             $objWriter->endElement();
 
@@ -362,9 +363,9 @@ class Drawing extends WriterPart
 
         // xml
         $objWriter->startElement('xml');
-        $objWriter->writeAttribute('xmlns:v', 'urn:schemas-microsoft-com:vml');
+        $objWriter->writeAttribute('xmlns:v', Namespaces::URN_VML);
-        $objWriter->writeAttribute('xmlns:o', 'urn:schemas-microsoft-com:office:office');
+        $objWriter->writeAttribute('xmlns:o', Namespaces::URN_MSOFFICE);
-        $objWriter->writeAttribute('xmlns:x', 'urn:schemas-microsoft-com:office:excel');
+        $objWriter->writeAttribute('xmlns:x', Namespaces::URN_EXCEL);
 
         // o:shapelayout
         $objWriter->startElement('o:shapelayout');
@@ -558,7 +559,7 @@ class Drawing extends WriterPart
         }
 
         $objWriter->startElement('a:hlinkClick');
-        $objWriter->writeAttribute('xmlns:r', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships');
+        $objWriter->writeAttribute('xmlns:r', Namespaces::SCHEMA_OFFICE_DOCUMENT);
         $objWriter->writeAttribute('r:id', 'rId' . $hlinkClickId);
         $objWriter->endElement();
     }

src/PhpSpreadsheet/Writer/Xlsx/Rels.php

@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Worksheet\BaseDrawing;
@@ -30,7 +31,7 @@ class Rels extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
 
         $customPropertyList = $spreadsheet->getProperties()->getCustomProperties();
         if (!empty($customPropertyList)) {
@@ -38,7 +39,7 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 4,
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/custom-properties',
+                Namespaces::RELATIONSHIPS_CUSTOM_PROPERTIES,
                 'docProps/custom.xml'
             );
         }
@@ -47,7 +48,7 @@ class Rels extends WriterPart
         $this->writeRelationship(
             $objWriter,
             3,
-            'http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties',
+            Namespaces::RELATIONSHIPS_EXTENDED_PROPERTIES,
             'docProps/app.xml'
         );
 
@@ -55,7 +56,7 @@ class Rels extends WriterPart
         $this->writeRelationship(
             $objWriter,
             2,
-            'http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties',
+            Namespaces::CORE_PROPERTIES,
             'docProps/core.xml'
         );
 
@@ -63,7 +64,7 @@ class Rels extends WriterPart
         $this->writeRelationship(
             $objWriter,
             1,
-            'http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument',
+            Namespaces::OFFICE_DOCUMENT,
             'xl/workbook.xml'
         );
         // a custom UI in workbook ?
@@ -72,7 +73,7 @@ class Rels extends WriterPart
             $this->writeRelationShip(
                 $objWriter,
                 5,
-                'http://schemas.microsoft.com/office/2006/relationships/ui/extensibility',
+                Namespaces::EXTENSIBILITY,
                 is_string($target) ? $target : ''
             );
         }
@@ -102,13 +103,13 @@ class Rels extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
 
         // Relationship styles.xml
         $this->writeRelationship(
             $objWriter,
             1,
-            'http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles',
+            Namespaces::STYLES,
             'styles.xml'
         );
 
@@ -116,7 +117,7 @@ class Rels extends WriterPart
         $this->writeRelationship(
             $objWriter,
             2,
-            'http://schemas.openxmlformats.org/officeDocument/2006/relationships/theme',
+            Namespaces::THEME2,
             'theme/theme1.xml'
         );
 
@@ -124,7 +125,7 @@ class Rels extends WriterPart
         $this->writeRelationship(
             $objWriter,
             3,
-            'http://schemas.openxmlformats.org/officeDocument/2006/relationships/sharedStrings',
+            Namespaces::SHARED_STRINGS,
             'sharedStrings.xml'
         );
 
@@ -134,7 +135,7 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 ($i + 1 + 3),
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet',
+                Namespaces::WORKSHEET,
                 'worksheets/sheet' . ($i + 1) . '.xml'
             );
         }
@@ -144,7 +145,7 @@ class Rels extends WriterPart
             $this->writeRelationShip(
                 $objWriter,
                 ($i + 1 + 3),
-                'http://schemas.microsoft.com/office/2006/relationships/vbaProject',
+                Namespaces::VBA,
                 'vbaProject.bin'
             );
             ++$i; //increment i if needed for an another relation
@@ -183,7 +184,7 @@ class Rels extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
 
         // Write drawing relationships?
         $drawingOriginalIds = [];
@@ -215,7 +216,7 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 $rId,
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/drawing',
+                Namespaces::RELATIONSHIPS_DRAWING,
                 $relPath
             );
         }
@@ -227,7 +228,7 @@ class Rels extends WriterPart
                 $this->writeRelationship(
                     $objWriter,
                     '_hyperlink_' . $i,
-                    'http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink',
+                    Namespaces::HYPERLINK,
                     $hyperlink->getUrl(),
                     'External'
                 );
@@ -242,14 +243,14 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 '_comments_vml' . $i,
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/vmlDrawing',
+                Namespaces::VML,
                 '../drawings/vmlDrawing' . $worksheetId . '.vml'
             );
 
             $this->writeRelationship(
                 $objWriter,
                 '_comments' . $i,
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/comments',
+                Namespaces::COMMENTS,
                 '../comments' . $worksheetId . '.xml'
             );
         }
@@ -260,7 +261,7 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 '_table_' . $i,
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/table',
+                Namespaces::RELATIONSHIPS_TABLE,
                 '../tables/table' . $tableRef++ . '.xml'
             );
         }
@@ -271,14 +272,14 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 '_headerfooter_vml' . $i,
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/vmlDrawing',
+                Namespaces::VML,
                 '../drawings/vmlDrawingHF' . $worksheetId . '.vml'
             );
         }
 
-        $this->writeUnparsedRelationship($worksheet, $objWriter, 'ctrlProps', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/ctrlProp');
+        $this->writeUnparsedRelationship($worksheet, $objWriter, 'ctrlProps', Namespaces::RELATIONSHIPS_CTRLPROP);
-        $this->writeUnparsedRelationship($worksheet, $objWriter, 'vmlDrawings', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/vmlDrawing');
+        $this->writeUnparsedRelationship($worksheet, $objWriter, 'vmlDrawings', Namespaces::VML);
-        $this->writeUnparsedRelationship($worksheet, $objWriter, 'printerSettings', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/printerSettings');
+        $this->writeUnparsedRelationship($worksheet, $objWriter, 'printerSettings', Namespaces::RELATIONSHIPS_PRINTER_SETTINGS);
 
         $objWriter->endElement();
 
@@ -325,7 +326,7 @@ class Rels extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
 
         // Loop through images and write relationships
         $i = 1;
@@ -340,7 +341,7 @@ class Rels extends WriterPart
                 $this->writeRelationship(
                     $objWriter,
                     $i,
-                    'http://schemas.openxmlformats.org/officeDocument/2006/relationships/image',
+                    Namespaces::IMAGE,
                     '../media/' . $drawing->getIndexedFilename()
                 );
 
@@ -359,7 +360,7 @@ class Rels extends WriterPart
                     $this->writeRelationship(
                         $objWriter,
                         $i++,
-                        'http://schemas.openxmlformats.org/officeDocument/2006/relationships/chart',
+                        Namespaces::RELATIONSHIPS_CHART,
                         '../charts/chart' . ++$chartRef . '.xml'
                     );
                 }
@@ -391,7 +392,7 @@ class Rels extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
 
         // Loop through images and write relationships
         foreach ($worksheet->getHeaderFooter()->getImages() as $key => $value) {
@@ -399,7 +400,7 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 $key,
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/image',
+                Namespaces::IMAGE,
                 '../media/' . $value->getIndexedFilename()
             );
         }
@@ -424,7 +425,7 @@ class Rels extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
 
         // Loop through images and write relationships
         foreach ($worksheet->getComments() as $comment) {
@@ -436,7 +437,7 @@ class Rels extends WriterPart
             $this->writeRelationship(
                 $objWriter,
                 $bgImage->getImageIndex(),
-                'http://schemas.openxmlformats.org/officeDocument/2006/relationships/image',
+                Namespaces::IMAGE,
                 '../media/' . $bgImage->getMediaFilename()
             );
         }
@@ -483,7 +484,7 @@ class Rels extends WriterPart
         $this->writeRelationship(
             $objWriter,
             $i,
-            'http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink',
+            Namespaces::HYPERLINK,
             $drawing->getHyperlink()->getUrl(),
             $drawing->getHyperlink()->getTypeHyperlink()
         );

src/PhpSpreadsheet/Writer/Xlsx/RelsRibbon.php

@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 
@@ -27,13 +28,13 @@ class RelsRibbon extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
         $localRels = $spreadsheet->getRibbonBinObjects('names');
         if (is_array($localRels)) {
             foreach ($localRels as $aId => $aTarget) {
                 $objWriter->startElement('Relationship');
                 $objWriter->writeAttribute('Id', $aId);
-                $objWriter->writeAttribute('Type', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/image');
+                $objWriter->writeAttribute('Type', Namespaces::IMAGE);
                 $objWriter->writeAttribute('Target', $aTarget);
                 $objWriter->endElement();
             }

src/PhpSpreadsheet/Writer/Xlsx/RelsVBA.php

@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 
@@ -27,10 +28,10 @@ class RelsVBA extends WriterPart
 
         // Relationships
         $objWriter->startElement('Relationships');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/package/2006/relationships');
+        $objWriter->writeAttribute('xmlns', Namespaces::RELATIONSHIPS);
         $objWriter->startElement('Relationship');
         $objWriter->writeAttribute('Id', 'rId1');
-        $objWriter->writeAttribute('Type', 'http://schemas.microsoft.com/office/2006/relationships/vbaProjectSignature');
+        $objWriter->writeAttribute('Type', Namespaces::VBA_SIGNATURE);
         $objWriter->writeAttribute('Target', 'vbaProjectSignature.bin');
         $objWriter->endElement();
         $objWriter->endElement();

src/PhpSpreadsheet/Writer/Xlsx/StringTable.php

@@ -5,28 +5,26 @@ namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 use PhpOffice\PhpSpreadsheet\Cell\Cell;
 use PhpOffice\PhpSpreadsheet\Cell\DataType;
 use PhpOffice\PhpSpreadsheet\Chart\ChartColor;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\RichText\RichText;
 use PhpOffice\PhpSpreadsheet\RichText\Run;
 use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
-use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet as ActualWorksheet;
 
 class StringTable extends WriterPart
 {
     /**
      * Create worksheet stringtable.
      *
-     * @param Worksheet $worksheet Worksheet
      * @param string[] $existingTable Existing table to eventually merge with
      *
      * @return string[] String table for worksheet
      */
-    public function createStringTable(Worksheet $worksheet, $existingTable = null)
+    public function createStringTable(ActualWorksheet $worksheet, $existingTable = null)
     {
         // Create string lookup table
         $aStringTable = [];
-        $cellCollection = null;
-        $aFlippedStringTable = null; // For faster lookup
 
         // Is an existing table given?
         if (($existingTable !== null) && is_array($existingTable)) {
@@ -85,7 +83,7 @@ class StringTable extends WriterPart
 
         // String table
         $objWriter->startElement('sst');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
+        $objWriter->writeAttribute('xmlns', Namespaces::MAIN);
         $objWriter->writeAttribute('uniqueCount', (string) count($stringTable));
 
         // Loop through string table

src/PhpSpreadsheet/Writer/Xlsx/Style.php

@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
@@ -37,7 +38,7 @@ class Style extends WriterPart
         // styleSheet
         $objWriter->startElement('styleSheet');
         $objWriter->writeAttribute('xml:space', 'preserve');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
+        $objWriter->writeAttribute('xmlns', Namespaces::MAIN);
 
         // numFmts
         $objWriter->startElement('numFmts');

src/PhpSpreadsheet/Writer/Xlsx/Table.php

@@ -3,6 +3,7 @@
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Worksheet\Table as WorksheetTable;
 
@@ -34,7 +35,7 @@ class Table extends WriterPart
 
         $objWriter->startElement('table');
         $objWriter->writeAttribute('xml:space', 'preserve');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
+        $objWriter->writeAttribute('xmlns', Namespaces::MAIN);
         $objWriter->writeAttribute('id', (string) $tableRef);
         $objWriter->writeAttribute('name', $name);
         $objWriter->writeAttribute('displayName', $table->getName() ?: $name);

src/PhpSpreadsheet/Writer/Xlsx/Theme.php

@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 
@@ -121,7 +122,7 @@ class Theme extends WriterPart
 
         // a:theme
         $objWriter->startElement('a:theme');
-        $objWriter->writeAttribute('xmlns:a', 'http://schemas.openxmlformats.org/drawingml/2006/main');
+        $objWriter->writeAttribute('xmlns:a', Namespaces::DRAWINGML);
         $objWriter->writeAttribute('name', 'Office Theme');
 
         // a:themeElements

src/PhpSpreadsheet/Writer/Xlsx/Workbook.php

@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\Shared\Date;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
@@ -32,8 +33,8 @@ class Workbook extends WriterPart
         // workbook
         $objWriter->startElement('workbook');
         $objWriter->writeAttribute('xml:space', 'preserve');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
+        $objWriter->writeAttribute('xmlns', Namespaces::MAIN);
-        $objWriter->writeAttribute('xmlns:r', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships');
+        $objWriter->writeAttribute('xmlns:r', Namespaces::SCHEMA_OFFICE_DOCUMENT);
 
         // fileVersion
         $this->writeFileVersion($objWriter);

src/PhpSpreadsheet/Writer/Xlsx/Worksheet.php

@@ -5,6 +5,7 @@ namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
 use PhpOffice\PhpSpreadsheet\Calculation\Information\ErrorValue;
 use PhpOffice\PhpSpreadsheet\Cell\Cell;
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx\Namespaces;
 use PhpOffice\PhpSpreadsheet\RichText\RichText;
 use PhpOffice\PhpSpreadsheet\Settings;
 use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
@@ -41,15 +42,15 @@ class Worksheet extends WriterPart
         // Worksheet
         $objWriter->startElement('worksheet');
         $objWriter->writeAttribute('xml:space', 'preserve');
-        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
+        $objWriter->writeAttribute('xmlns', Namespaces::MAIN);
-        $objWriter->writeAttribute('xmlns:r', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships');
+        $objWriter->writeAttribute('xmlns:r', Namespaces::SCHEMA_OFFICE_DOCUMENT);
 
-        $objWriter->writeAttribute('xmlns:xdr', 'http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing');
+        $objWriter->writeAttribute('xmlns:xdr', Namespaces::SPREADSHEET_DRAWING);
-        $objWriter->writeAttribute('xmlns:x14', 'http://schemas.microsoft.com/office/spreadsheetml/2009/9/main');
+        $objWriter->writeAttribute('xmlns:x14', Namespaces::DATA_VALIDATIONS1);
-        $objWriter->writeAttribute('xmlns:xm', 'http://schemas.microsoft.com/office/excel/2006/main');
+        $objWriter->writeAttribute('xmlns:xm', Namespaces::DATA_VALIDATIONS2);
-        $objWriter->writeAttribute('xmlns:mc', 'http://schemas.openxmlformats.org/markup-compatibility/2006');
+        $objWriter->writeAttribute('xmlns:mc', Namespaces::COMPATIBILITY);
         $objWriter->writeAttribute('mc:Ignorable', 'x14ac');
-        $objWriter->writeAttribute('xmlns:x14ac', 'http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac');
+        $objWriter->writeAttribute('xmlns:x14ac', Namespaces::SPREADSHEETML_AC);
 
         // sheetPr
         $this->writeSheetPr($objWriter, $worksheet);