Dynamic text on TCPDF-Laravel footer-CodePudding

First of all I'm 90% sure this is me not knowing some basic stuff about how php static methods work, so please forgive my ignorance. I also could not find any info on this on SO, so hopefully this won't be a duplicate.

I'm working on a project with laravel and using the TCPDF-Laravel extension, and I have a footer that needs to say different things based on a condidition:

   if ($someCondition) {
         $footerText = <<<EOD
                text if true
          EOD;
    } else {
         $footerText = <<<EOD
                text if false
          EOD;
     }

    PDF::setFooterCallback(function($pdf,$footerText){
        $pdf->SetY(-15);
        $pdf->Write(0, $footerText, '', 0, 'L', true, 0, false, false, 0);
    });

But for some reason, again probably my ignorance, this doesn't run. It says 'too few arguments given', as if $footerText wasn't defined or was null.

I have already tried declaring the variable before the if bracket, declaring the function outside the setFooterCallBack, and using $this->footerText but it didn't work.

CodePudding user response：

Ok to make this simple.

PDF::setFooterCallback() requires a callable as a first argument. That's where you pass in function($pdf) {}. In order to expand the functions scope for a variable like $footerText, you have to use use to inherit it like so: function($pdf) use($footerText).

The reason why you get this error is because you set $footerText as a second argument after $pdf, which setFooterCallback does not know of and therefor, it's not set and calls a too few arguments exception which is normal.

// outputs "Howdy'ho!"
(function($what) {
    echo $what;
})("Howdy'ho!");


// will throw an exception `too few arguments`
(function($what) {
    echo $what;
})();

// will output null, because it can be called without an argument.
(function($what = null) {
    echo $what;
})();

So theoretically, setting $footerText to a default null would work, but this is of course not what you intended to do.

PDF::setFooterCallback(function($pdf, $footerText = null){
  $pdf->SetY(-15);
  $pdf->Write(0, $footerText, '', 0, 'L', true, 0, false, false, 0);
});

Just inherit the variable $footerText using use.

PDF::setFooterCallback(function($pdf) use(footerText) {
  $pdf->SetY(-15);
  $pdf->Write(0, $footerText, '', 0, 'L', true, 0, false, false, 0);
});