Unable to read data from file for class derived from Spreadsheet

[APochmann]

I use a class derived from Spreadsheet class for some initialization and functions which works pretty fine as long as the objects are created with new MySpreadsheet. However, wen trying to read a file (Excel in my case) I have to use the Xlsx reader but this always creates new object with class Spreadsheet and I don't see any possibility to get this object to behave as MySpreadsheet as object cast is not possible.

Simplified code sniplet to explain what I try to get:

class MySpreadsheet extends Spreadsheet
{
    public function __construct(array $myData){
        parent::__construct();
        /* Do stuff with myData */
	}
    public function doStuff() {
        /* Do stuff here */
	}
}

// This works fine
$spreadsheet = new MySpreadsheet($someData);
$spreadsheet->doStuff();

// this fails as $preadsheet is of class Spreadsheet
$reader = new Reader\Xlsx();
$spreadsheet = $reader->load('file.xlsx');
$spreadsheet->doStuff();     // This has to fail as doStuff() is not defined for Spreadsheet

I did not find a way without modifying the reader by accepting a Spreadsheet instance as parameter and fill this one with data. I can hand over a MySpreadsheet object without problems.

Modification from:

    protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
    {
        File::assertFile($filename, self::INITIAL_FILE);
        // Initialisations
        $excel = new Spreadsheet();
...

to:

    protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
    {
        return $this->loadFromFileToSpreadsheet($filename);
    }
	
    public function loadFromFileToSpreadsheet(string $filename, ?Spreadsheet $spreadsheet=null): Spreadsheet
    {
        File::assertFile($filename, self::INITIAL_FILE);
        // Initialisations
        $excel = $spreadsheet ?? new Spreadsheet();
...

With this modification:

// This works fine
$spreadsheet = new MySpreadsheet($someData);
$reader = new reader\Xlsx();
$reader->loadFromFileToSpreadsheet('file.xlsx', $spreadsheet);
$spreadsheet->doStuff();     // Now doStuff() is available

Is there something I missed and has anybody an idea how I can get this working without modifying the reader?

[oleibman]

The code at https://gist.github.com/eduardokum/ce8d0e937ed9136b713cc0790ce790be looks like it would solve your problem.

$reader = new Reader\Xlsx();
$spreadsheet = $reader->load('filename');
$mySpreadsheet = cast($spreadsheet, MySpreadsheet::class);
var_dump($mySpreadsheet->getActiveSheet()->getCell('A1')->getValue()); // appears to work
$mySpreadsheet->doStuff(); // appears to work

[APochmann]

Thanks for pointing to that function, looks interesting and I tried it. I was afraid that I would get an issue with memory as the Excel files are quite large but then I ran into an exception as serializing of Spreadsheet objects is not possible at all (code from Spreadsheet.php):

    public function __serialize()
    {
        throw new Exception('Spreadsheet objects cannot be serialized');
    }

[oleibman]

Serialization is permitted in release 4.0.

[oleibman]

PR #4404 addresses this.