Allow setting of header content type for CSVs.

src/Spout/Writer/AbstractWriter.php

@@ -37,7 +37,7 @@ abstract class AbstractWriter implements WriterInterface
     protected $defaultRowStyle;
 
     /** @var string Content-Type value for the header - to be defined by child class */
-    protected static $headerContentType;
+    protected $headerContentType;
 
     /**
      * Opens the streamer and makes it ready to accept data.
@@ -143,7 +143,7 @@ abstract class AbstractWriter implements WriterInterface
         $this->globalFunctionsHelper->ob_end_clean();
 
         // Set headers
-        $this->globalFunctionsHelper->header('Content-Type: ' . static::$headerContentType);
+        $this->globalFunctionsHelper->header('Content-Type: ' . $this->headerContentType);
         $this->globalFunctionsHelper->header('Content-Disposition: attachment; filename="' . $this->outputFilePath . '"');
 
         /*

src/Spout/Writer/CSV/Writer.php

@@ -18,7 +18,7 @@ class Writer extends AbstractWriter
     const FLUSH_THRESHOLD = 500;
 
     /** @var string Content-Type value for the header */
-    protected static $headerContentType = 'text/csv; charset=UTF-8';
+    protected $headerContentType = 'text/csv; charset=UTF-8';
 
     /** @var string Defines the character used to delimit fields (one character only) */
     protected $fieldDelimiter = ',';
@@ -58,6 +58,18 @@ class Writer extends AbstractWriter
         return $this;
     }
 
+    /**
+     * Set the header content type.
+     *
+     * @param string $headerContentType Content-Type value for the header if different than default UTF-8.
+     * @return Writer
+     */
+    public function setHeaderContentType($headerContentType)
+    {
+        $this->headerContentType = $headerContentType;
+        return $this;
+    }
+
     /**
      * Set if a BOM has to be added to the file
      *

src/Spout/Writer/ODS/Writer.php

@@ -15,7 +15,7 @@ use Box\Spout\Writer\ODS\Internal\Workbook;
 class Writer extends AbstractMultiSheetsWriter
 {
     /** @var string Content-Type value for the header */
-    protected static $headerContentType = 'application/vnd.oasis.opendocument.spreadsheet';
+    protected $headerContentType = 'application/vnd.oasis.opendocument.spreadsheet';
 
     /** @var string Temporary folder where the files to create the ODS will be stored */
     protected $tempFolder;

src/Spout/Writer/XLSX/Writer.php

@@ -19,7 +19,7 @@ class Writer extends AbstractMultiSheetsWriter
     const DEFAULT_FONT_NAME = 'Calibri';
 
     /** @var string Content-Type value for the header */
-    protected static $headerContentType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
+    protected $headerContentType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
 
     /** @var string Temporary folder where the files to create the XLSX will be stored */
     protected $tempFolder;