Question

I thought I can call a method directly with classname::method but it didn’t work. How is this possible? I traced the function call with xdebug but it gives me an error. Would it be a problem when the method needs some class variable?

This works:

    $a = new export_csv();
    $a->dl_csv();

This don’t: export_csv::dl_csv();

I’ve added public static to my method to no avail. I don’t get anything in the log files and xdebug stop working without an error message? Is this normal? My class includes some class and connect to my database and pull and echo some rows?

 require_once(PATH_t3lib.'class.t3lib_db.php');
 require_once(PATH_t3lib.'class.t3lib_div.php');
 require_once(PATH_t3lib.'utility/class.t3lib_utility_math.php');

 class export_csv 
 {
     var $filename = 'meinname.csv';

     public static function dl_csv()
     {
        // bitte nicht ändern muß zur laufzeit geladen werden
        include(PATH_typo3conf.'localconf.php');

        $GLOBALS['TYPO3_DB'] = t3lib_div::makeInstance('t3lib_DB');
        $GLOBALS['TYPO3_DB']->connectDB($typo_db_host, $typo_db_username,   
            $typo_db_password, $typo_db);

        session_start();
            $targetCat = mysql_real_escape_string($_SESSION['targetCat']);

            // calculate the number of rows for the query. We need this for paging the 
            result
            $res = $GLOBALS['TYPO3_DB']->exec_SELECTquery(  'V.title VT, V.uid VU,  
            S.title ST, S.uid SU, S1.uid S1U, S1.title S1T',
                                                    'tx_category V
                                                    INNER JOIN tx_category S ON  

                                                    V.parent_category=S.uid
                                                    INNER JOIN tx_category S1 ON 
                                                    S.parent_category=S1.uid',
                                                    'V.uid='.$targetCat.' OR S.uid='.
                                                     $targetCat.' OR S1.uid='.
                                                     $targetCat.
                                                    ' AND V.deleted=0 AND V.hidden=0',
                                                    '',
                                                    '',
                                                    ''
                            );                      
    $arrcount=0;
    while ( $row = $GLOBALS['TYPO3_DB']->sql_fetch_assoc($res) )
    {
        $categories[] = mysql_real_escape_string($row["VU"]);
        ++$arrcount;
    }

    header("Pragma: public");
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: public");
    header("Content-Description: File Transfer");
    header("Content-Type:text/comma-separated-values");
    header("Content-Transfer-Encoding: binary");
    header("Content-Disposition: attachment; filename=$this->filename");

    if ( $arrcount )
    {
        $res = $GLOBALS['TYPO3_DB']->exec_SELECTquery('*',
                                                      'tx_download',
                                                      'category IN('.implode(",",
                                                      $categories).")",
                                                      '',
                                                      "",
     ""                                                  
                                                    );
        while ($row = mysql_fetch_assoc($res) )
        {
            $s = array ();
            $s[] = $row['1'];
            $s[] = $row['2'];
            $s[] = $row['3'];
            $s[] = $row['4'];
            $s[] = $row['5'];

            echo '"'. substr ( implode ( '","', $s ),0,strlen ( implode ( '","', $s) ) - 2  ) . "\r\n";

        }       
    }
  }
 }

Answer 1

Methods defined as static, which therefore cannot make use of instance properties/methods (via $this) can be called statically via:

ClassName::methodname();

// Static method definition:
public static function methodname() {
  echo "I'm the method, I don't use \$this in any way!";
  // Any attempt to use $this in here would result in error.
}

Review the PHP documentation on static methods and properties

Update after seeing mode code:

Your dl_csv() function accesses $this->filename in the output headers, which is invalid inside a static call.

// Can't do this!
header("Content-Disposition: attachment; filename=$this->filename");

Instead, you would need to define the $filename as a static property as well and call via self:::

// Top of the class:
// Instead of the old PHP4 var keyword, define $filename as a public static property
public static $filename = 'meinname.csv';

// Later...
// Inside your method header() call:
header("Content-Disposition: attachment; filename=" . self::$filename);