[PHP - LARAVEL] READ & WRITE FILE TXT

$req = $request->all();
$email = $req['email'];

function writeTXT($texto){
    $fp = fopen('data.txt', 'a');
    fwrite($fp, $texto."\n");
    fclose($fp);
}


function readTXT($email){
    $filename = "data.txt";
    $handle = fopen($filename, "r");
    $contents = fread($handle, filesize($filename));

    fclose($handle);

    $variavel = $contents;
    $a = str_replace(' """ ','',$variavel);
    $b = str_replace("\n",",",$a);
    $array = explode(',', $b);

    if (stripos(json_encode($array),$email) !== false) {
        return true;
    }else{
        return false;
    }
}

readTXT($email);

if (readTXT($email) == true) {
    //nao faz nada;
}else{
    writeTXT($email);
}

return back();