Drupal: Newsletter block

This connects to an abstract class that outputs different types of file formats for newsletter data. This is just the Drupal bit.

define('EMAIL_ADDRESS_TO',      'xxxxx@xxxxxxxxxx.co.uk');
define('EMAIL_ADDRESS_FROM',    'admxxxxxin@xxxxxxxxxx.co.uk');
define('EMAIL_SUBJECT_ADD',     'subscribe');
define('EMAIL_SUBJECT_REMOVE',  'unsubscribe');


/**
 * Implementation of hook_block
 */

function dbnewsletter_block($op = 'list', $delta = 0, $edit = array()) {
	$blocks = array() ;

	switch ($op) {
		case 'list':
			$blocks['dbnewsletter_subs']['info'] = t('Newsletter subscribe/unsubscribe') ;
			break ;
		case 'view':
			switch ($delta) {
				case 'dbnewsletter_subs':
					$blocks['subject'] = null ;
					
          $blockregion = db_result(db_query("SELECT region FROM {blocks} WHERE delta = '%s' AND theme = '%s'", 'dbnewsletter_subs', 'theme1'));
					
					if ($blockregion == 'front_middle_column') {
						$blocks['content'] = 'Newsletter'.
	                               _dbnewsletter_subs_block();
					}
          if ($blockregion == 'front_left_column') {
            $blocks['content'] = 'Newsletter'.
                                  _dbnewsletter_subs_block();
          }
					
			}
			break ;
	}

	return $blocks ;
}

function _dbnewsletter_subs_block() {
  return drupal_get_form('dbnewsletter_subs_form');
}

function theme_dbnewsletter_subs_form($form) {
	$ret  = '
';
	$ret .= '  
';
	$ret .= '    
';
	$ret .= '      
';
	$ret .= drupal_render($form['blurb']);
	$ret .= '        
';
	$ret .= '          E-mail:
';
	$ret .= drupal_render($form['dmail']);
	$ret .= '        
';
	$ret .= '        
';
	$ret .= drupal_render($form['sub']);
	$ret .= '        
';
	$ret .= '        
';
	$ret .= drupal_render($form['submit']);
	$ret .= '        
';
	$ret .= '      
';
	$ret .= '    
';
	$ret .= '  
';
	$ret .= '
';
	$ret .= drupal_render($form);
	return $ret;
}



function dbnewsletter_subs_form() {
	$form = array() ;
	$weight = -10 ;
	$form['blurb'] = array(
		'#value' => '
' . t('Stay informed with the latest news') . '
',
		'#weight' => $weight++,
	) ;
	$form['dmail'] = array(
    '#nomarkup' => 1,
		'#type' => 'textfield',
		'#title' => t('Email'),
		'#size' => 42,
    '#attributes' => array('class' => 'tx'),
		'#required' => false, // we set this false so we can use the form_set_error message in the validate hook
		'#weight' => $weight++,
	) ;
	$form['sub'] = array(
    '#nomarkup' => 1,
		'#type' => 'radios',
		'#options' => array(t('Subscribe'), t('Unsubscribe')),
		'#default_value' => 0,
		'#required' => true,
		'#weight' => $weight++,
	) ;
	$form['submit'] = array(
    '#nomarkup' => 1,
		'#type' => 'submit',
		'#value' => t('Submit'),
		'#weight' => $weight++,
	) ;

	return $form ;
}

function dbnewsletter_subs_form_validate($form_id, $form_values) {
//	print_r($form_values); exit;
  if ($form_values['dmail'] == '') {
  	form_set_error('dmail', t('Please enter an email address into the newsletter box'));
  }
	if (!valid_email_address($form_values['dmail'])) {
		form_set_error('dmail', t('The email address you provided is not valid')) ;
	}
}

function dbnewsletter_subs_form_submit($form_id, $form_values) {
//	print_r($form_values); exit;
	switch ($form_values['sub']) {
		case 0:
			dbnewsletter_add($form_values['dmail']) ;
			drupal_set_message(t('Thank you, your email address has been added')) ;
			// send email:
			$to = EMAIL_ADDRESS_TO;
			$from = EMAIL_ADDRESS_FROM;
			$subj = EMAIL_SUBJECT_ADD;
			$msg = 'new subscriber to the newsletter: ' . $form_values['dmail'];
			drupal_mail('newsletter', $to, $subj, $msg, $from);
			break ;
		case 1:
			dbnewsletter_del($form_values['dmail']) ;
			drupal_set_message(t('Your email address has been removed')) ;
			$to = EMAIL_ADDRESS_TO;
			$from = EMAIL_ADDRESS_FROM;
			$subj = EMAIL_SUBJECT_REMOVE;
			$msg = 'this person unsubscribed from the newsletter: ' . $form_values['dmail'];
			drupal_mail('newsletter', $to, $subj, $msg, $from);
			break ;
	}
	list(,$path) = explode('=', drupal_get_destination()) ;
	if ($path=='frontpage') $path='' ;
	return urldecode($path) ;
}

function dbnewsletter_add($dmail) {
	dbnewsletter_del($dmail) ;
	db_query("INSERT INTO {dbnewsletter_email} (dmail) VALUES ('%s')", $dmail) ;
}

function dbnewsletter_del($dmail) {
	db_query("DELETE FROM {dbnewsletter_email} WHERE dmail='%s'", $dmail) ;
}


/**
 * Implementation of hook_menu
 */
function dbnewsletter_menu($may_cache) {
	$items = array() ;
	if (!$may_cache) {
		$items[] = array(
			'path' => 'subscribers',
			'title' => t('Fetch newsletter emails'),
			'access' => user_access('administer nodes'),
			'callback' => 'dbnewsletter_export',
			'type' => MENU_CALLBACK
		) ;
	}
	return $items ;
}

function dbnewsletter_export($type = 'xls') {
	if ($exporter = dbnewsletterExport::factory($type)) {
		$exporter->export() ;
		exit ;
	}
	return ' ' ;
}