Why is this code trying to send header information

[rythmic]

Problem: I am trying to do a header("locatio n: $url"); call.

Here is the error message:

Warning: Cannot modify header information - headers already sent by (output started at D:\dev\web\brfc irkusprinsessan \dev\classes\Ne wsItem.php:1) in D:\dev\web\brfc irkusprinsessan \dev\handlers\f orm_handler.php on line 53

The header location call is the line 53 in the error message. Below is the code for the NewsItem class. If I comment the usage of the NewsItem class everything works fine, so logic suggests something is wrong in the NewsItem class, but I don't see it.

The error appears even if I don't use the if statement where the NewsItem class is used.

Does anyone see the problem?

first here is the form_handler.ph p code which has the error on line 54

<?php
session_start();

require_once '../classes/Calendar.php';
require_once '../classes/DBEasy.php';
require_once '../classes/Email.php';
require_once '../classes/NewsHolder.php';
require_once '../classes/NewsItem.php';

    $widget = $_POST['widget'];
    $action = $_POST['action'];
    $db_id = $_POST['dbid'];
    $location = getenv('HTTP_REFERER');
    // *** dispatcher code ***
    //
    // calendar update
    if ( $widget == 'calendar' && $action == 'update') {
        $cal = new Calendar($db_id);
        $cal->set_title($_POST['title']);
        $cal->set_description($_POST['desc']);
        $cal->save();
    }
    else if ($action=='doemail') {
        $to = 'styrelsen@example.com';
        $sub = 'Nytt kontaktmail - ' . $_POST['sub'];
        $msg = $_POST['msg'];
        $sender = 'hemsidan@example.com';
        $sender_name = 'Hemsidans kontaktform';
        //construct($recipient, $subject,$message,$sender,$sender_name='',$recipient_name='')
        $email = new Email($to,$sub,$msg,$sender,$sender_name);

        Email::send($email);
    }
    else if ( $widget == 'newsholder' && $action == 'update') {
        $nh = new NewsHolder($db_id);
        $nh->set_title($_POST['title']);
        $nh->set_description($_POST['desc']);
        $nh->set_max_news_displayed($_POST['max_news_displayed']);
        $nh->set_max_news_message_length($_POST['max_news_message_length']);
        $nh->save();
    }
    
    else if ( $widget == 'newsitem' && $action == 'update') {
        $ni = new NewsItem($db_id);
        $ni->set_title($_POST['title']);
        $ni->set_message($_POST['message']);
        //TODO: add image id handling
        $ni->save();

    }

    // after updating the data model go back to referring page
    header('Location: ' . $location);
?>

And here's the NewsItem class

 <?php
    class NewsItem {

        private $db_id;
        private $newsholder_id;
        private $author_id;
        private $creation_date;
        private $title;
        private $message;
        private $image_url;

        private $editable = false;
        private $use_lightbox_view = true;
        private $use_lightbox_edit = true;

        public function __construct($db_id=-1) {

            if ( $db_id != -1 ) {
                $this->fetch($db_id);

                if ( is_null( $this->db_id ) ) {
                    // handle error
                }
              }
          }

          public function get_db_id() {
                return $this->db_id;
          }

          public function get_newsholder_id() {
              return $this->newsholder_id;
          }

          public function set_newsholder_id($newsholder_id) {
              $this->newsholder_id = $newsholder_id;
          }

          public function get_author_id() {
            return $this->author_id;
          }

          public function set_author_id($author_id) {
            $this->author_id = $author_id;
          }

          public function get_creation_date() {
            return $this->creation_date;
          }

          public function get_title() {
            return $this->title;
          }

          public function set_title($title) {
            $this->title = $title;
          }

          public function get_message() {
            return $this->message;
          }

          public function set_message($message) {
            $this->message = $message;
          }

          public function get_image_url() {
            return $this->image_url;
          }

          public function set_image_url($url) {
            $this->image_url = $url;
          }

          public function get_editable() {
              return $this->editable;
          }

          public function set_editable($editable) {
              $this->editable = $editable;
          }


          /**
          * @desc populates this NewsItem with data from the News containing the given
          * db_id;
          */
          private function fetch($db_id) {
            $tbl = 'news_items';
            $cols = array('news_item_id','news_holder_id', 'author_id', 'creation_date', 'title','message','image_url');
            $db = new DBEasy($tbl, $cols);

            $rows = $db->conditional_select(array(array('news_item_id','=','"' . $db_id .'"' )));


            //if results - add values to fields
            if ( count($rows) > 0 ) {
                $this->db_id= $rows[0]['news_item_id'];
                $this->newsholder_id = $rows[0]['news_holder_id'];
                $this->author_id= $rows[0]['author_id'];
                $this->creation_date= $rows[0]['creation_date'];
                $this->title = $rows[0]['title'];
                $this->message = $rows[0]['message'];
                $this->image_url = $rows[0]['image_url'];
            }

          }

          public function save() {
              $tbl = 'news_items';
              $cols = array('news_item_id','news_holder_id', 'author_id', 'creation_date', 'title','message','image_url');
              $value_pairs = array('news_holder_id'=>$this->newsholder_id, 'author_id'=>$this->author_id, 'creation_date'=>$this->creation_date, 'title'=>$this->title,'message'=>$this->message,'image_url'=>$this->image_url);
              $db = new DBEasy($tbl, $cols);

              //insert
            if (is_null($this->db_id) || $this->db_id == -1) {
                $success = $db->insert($value_pairs);
            }
            //update
            else {
                $success = $db->conditional_update($value_pairs, array(array( 'news_item_id','=',$this->db_id)));
            }

          }

          public function get_date($style=1) {
              if ($style == 1)
                return substr($this->creation_date, 0,10);
              else if ($style == 2) {
                  return substr($this->creation_date,9,1) . '/' . substr($this->creation_date,6,2) . substr($this->creation_date, 0,4);
              }
              else if ($style == 3) {
                return substr($this->creation_date,9,1) . ' ' . self::get_month_name(substr($this->creation_date,6,2)) . ' ' . substr($this->creation_date, 0,4);
              }
              else if ($style == 4) {
                return substr($this->creation_date,9,1) . ' ' . self::get_month_name(substr($this->creation_date,6,2),true) . ' ' . substr($this->creation_date, 0,4);
              }

          }

          public static function get_month_name($nbr, $full_name= false) {
              if (!$full_name)
                $month_names = array('jan','feb','mar','apr','maj','jun','jul','aug','sep','okt','nov','dec');
              else
                $month_names = array('januari','februari','mars','april','maj','juni','juli','augusti','september','oktober','november','december');
              return $month_names[$nbr-1];
        }

        public function present_message($max_length = 0) {
            if ( $max_length == 0)
                return $this->message;

            $disallowed_end_arr = array(',','.','!','?','-',';',':'."'");
            if ( strlen($this->message) > $max_length ) {

                for($i = $max_length; $i > 0; $i--) {
                    if ( strcmp(substr($this->message,$i,1),' ') === 0 )
                        if ( strcmp(substr($this->message,($i-1),1),',' ) === 0 ) {
                            return substr($this->message,0,$i-1) . '...';
                        }
                        else
                            return substr($this->message,0,$i) . '...';
                }
            }
            else
                return $this->message;
        }


          public function render($max_length = 0) {

                if ( $this->use_lightbox_edit)
                    $class = 'lbOn';
                else
                    $class = '';
                $edit_link = '<a class="' . $class . '" href="adm_edit_news_item.php?ni=' . $this->db_id . '">Redigera</a>';
                $code = array();

                $code[] = '<div class="news_item" style="border:1px solid #000;margin:10px 3px;padding:0;">' ."\n";
                $code[] = '<div class="news_item_header" style="background-color:#000;border-bottom:1px solid #000;">';
                $code[] = '<h5 class="news_date" style="color:#555;font-family:verdana;font-size:10px;font-style:italic;padding: 2px 5px 2px 10px;;margin:0;text-align:right;">' . $this->get_date(4) . "</h5>";
                $code[] = '<h4 class="news_rubrik" style="color:#ddd;font-family:arial;font-size:12px;font-weight:bold;padding:2px 10px 2px 5px;margin:0;">' . $this->title . '</h4>';
                if ($this->editable)
                    $code[] = '<h4 class="news_rubrik" style="color:#ddd;font-family:arial;font-size:12px;font-weight:bold;padding:2px 10px 2px 5px;margin:0;">' . $edit_link . '';

                $code[] = "</div>";
                $code[] = '<div class="news_text" style="background-color:#eee;padding: 3px 5px;">' . $this->present_message($max_length);
                //$code[] = '<div class="news_text" style="background-color:#f00;padding: 3px 5px; color:#fff;">' . $max_length;
                if ($max_length != 0 && strlen($this->message) > $max_length) {
                    if ($this->use_lightbox_view)
                            $class = 'lbOn';
                    else
                        $class = '';
                    $code[] = '<br /><a class="'.$class.'" href="nyheter.php?nh=' . $this->newsholder_id . '&id=' . $this->db_id . '" title="L&auml;s hela nyheten: ' . $this->title . '">L&auml;s mer...</a>';
                }
                $code[] = "</div>";
                $code[] = "</div>";

                return join("\n", $code);
          }

          public function render_thumbnail_image() {

          }

      }
?>

Best regards
Rythmic

[Dormilich]

see CNP: Headers already sent (Bytes Articles)

[rythmic]

Solved

Killer article. Thanks Dormilich and Markus

It was one of the more rare causes, an accidental whitespace before the <?php opening tag.