phplist_subscribe.module

<?php

/**
 * @file
 * Provides a block for subscribing to PHPList lists.
 *
 * @todo: Add a page for managing subscriptions.
 */

/* Defines constants. */

// PHPList database.
// @todo: Allow users to set in settings form.
define('PHPLIST_DBNAME', 'phplist');
  
// Error reporting.
define('PHPLIST_LIST_RETURN_CODE_SUCCESS', 0);
define('PHPLIST_LIST_RETURN_CODE_ERROR', 1);
define('PHPLIST_LIST_RETURN_CODE_ALREADY_SUBSCRIBED', 2);

// ID of list to which to subscribe
define('PHPLIST_LIST_LIST_ID', 2);

// Message texts for user history table.
define('TEXT_SUMMARY', 'Subscription');
define('TEXT_DETAIL', 'Subscribe page: 1   List Membership:   * ChristianVolunteering Marketing');

// Site homepage URL.
define('SITE_HOMEPAGE', 'home');

// Set the module in debug mode. 
// Switch to FALSE to stop printing error messages.
define('PHPLIST_MODULE_IN_DEBUG', TRUE); 

/**
 * Implements hook_init().
 */
function phplist_subscribe_init() {
  // add a custom JS file to change the destination of the form on tm homepage
  if(arg(0) == SITE_HOMEPAGE) {
    drupal_add_js(drupal_get_path('module', 'phplist_subscribe') . '/phplist_subscribe.js', array('type' => 'file', 'scope' => 'footer', 'every_page' => FALSE, 'cache' => FALSE, 'preprocess' => FALSE));    
  }
}

/**
 * Implements hook_block_info().
 */
function phplist_subscribe_block_info() {
  $blocks[0] = array(
    'info' => t('PHPList Subscribe'),
  );
  return $blocks;
}

/**
 * Implements hook_block_view().
 */
function phplist_subscribe_block_view($delta = 0) {
  switch ($delta) {
    case 0:
      $block = array(
        'subject' => t('Subscribe to Our Mailing List'),
        'content' => drupal_get_form('phplist_subscribe_email_form'),
      );
      break;
  }
  return $block;
}

/**
 * FormAPI form for subscribing to PHPList list.
 */
function phplist_subscribe_email_form($form, &$form_state) {
 $form = array(
   'email' => array(
     '#type' => 'textfield',
     '#title' => t('Email Address'),
     '#required' => 1,
     '#size' => 30,
   ),
   'submit' => array(
     '#type' => 'submit',
     '#value' => t('Subscribe'),
   ),
   '#validate' => array('phplist_subscribe_email_form_validate'),
   '#submit' => array('phplist_subscribe_email_form_submit'),
 );
 return $form;
}

/**
 * Validate handler for subscribing to PHPList list.
 */
function phplist_subscribe_email_form_validate($form, &$form_state) {
  if (user_validate_mail($form_state['values']['email'])) {
    form_set_error('email', t('Your email address is invalid.'));
  }
}

/**
 * Submit handler for subscribing to PHPList list.
 */
function phplist_subscribe_email_form_submit($form, &$form_state) {
  // Subscribe to list.
  $response = phplist_subscribe_to_list($form_state['values']['email'], PHPLIST_LIST_LIST_ID);
  // Handle any user-facing errors.
  _phplist_handle_response($response, PHPLIST_LIST_LIST_ID);
}

/**
 * Subscribes a user to a mailing list.
 * 
 * Call in submit handler 
 *   phplist_subscribe_to_list($form_state['values']['email'], MAILING_LIST_LIST_ID)
 * 
 * @param string $email
 * @return string
 */
function phplist_subscribe_to_list($email, $list_id) {
 // Is this email already in our system?
 $found_email = FALSE;
 db_set_active(PHPLIST_DBNAME);
 $result = db_query('select u.id from phplist_user_user u where u.email = :email',array(':email' => $email));

 if($result->rowCount() > 0) {
   // Yes, we already have the email in our db
   $found_email = TRUE;
   $userid = $record->fetchField();

   // Is the email already subscribed to the mailing list?
   $result = db_query('select userid from phplist_listuser where listid = :listid and userid = :userid', array(':listid' => $list_id, ':userid' => $userid));
   if($result->rowCount() > 0) {
     // Yes, the email is already subscribed
     return PHPLIST_LIST_RETURN_CODE_ALREADY_SUBSCRIBED;
   }
 }

 // The following inserts may fail, so wrap in a transaction for rollback.
 $transaction = db_transaction();
 try {
   if(!$found_email) {
     // The email was not already in our db, so we need to insert it.
     $result = db_insert('phplist_user_user')
       ->fields(array(
         'email' => $email,
         'entered' => date("Y-m-d H:i:s"),
         'modified' => date("Y-m-d H:i:s"),
         'uniqid' => uniqid(),
         'htmlemail' => 1,
         'subscribepage' => 1
       ))
       ->execute();
    // Get the user id for the newly inserted user
    $userid = db_query("select id from phplist_user_user where email = :email", array(':email' => $email))->fetchField();
   }

   // Insert subscription.
   $result = db_insert('phplist_listuser')
     ->fields(array(
       'userid' => $userid,
       'listid' => $list_id,
       'entered' => date("Y-m-d H:i:s"),
       'modified' => date("Y-m-d H:i:s")
     ))
     ->execute();

   // Insert user history.
   $result = db_insert('phplist_user_user_history')
     ->fields(array(
       'userid' => $userid,
       'ip' => $_SERVER['REMOTE_ADDR'],
       'date' => date("Y-m-d H:i:s"),
       'summary' => TEXT_SUMMARY,
       'detail' => TEXT_DETAIL,
       'systeminfo' => _phplist_get_sysinfo()
     ))
     ->execute();
 }
 catch(Exception $e) {
   $transaction->rollback();
   db_set_active();
   _phplist_debug('Exception ' . $e::toString);
 }
 db_set_active();
 return PHPLIST_LIST_RETURN_CODE_SUCCESS;
}

/**
 * Helper function: Handles the response from the subscription.
 * 
 * @return void
 */
function _phplist_handle_response($response, $list_id) {
  $listname = _phplist_get_listname($list_id);
  if(empty($listname)) {
    $listname = 'default';
  }
  switch($response) {
    case PHPLIST_LIST_RETURN_CODE_SUCCESS:
      drupal_set_message(t('You have been subscribed to the %listname list.',
        array('%listname' => $listname)));
      break;
    case PHPLIST_LIST_RETURN_CODE_ALREADY_SUBSCRIBED:
      drupal_set_message(t('You are already subscribed to the %listname list.', 
        array('%listname' => $listname)));
      break;
    case PHPLIST_LIST_RETURN_CODE_ERROR:
    default:
      drupal_set_message(t('An error occurred. You have not been subscribed to the %listname list.', 
        array('%listname' => $listname))); 
  }
  return; 
}

/**
 * Helper function: Gets the name of a PHPList list by id.
 */
function _phplist_get_listname($list_id) {
  db_set_active(PHPLIST_DBNAME);
  $listname = html_entity_decode(db_query('select name from phplist_list where id = :list_id', array(':list_id' => $list_id))->fetchField());
  db_set_active();
  return $listname;
}

/**
 * Utility function: Returns a string with various information about the user's browser.
 * 
 * @return string
 */
function _phplist_get_sysinfo() {
  $attributes = array('HTTP_USER_AGENT', 'HTTP_REFERER', 'REMOTE_ADDR');
  $sysinfo = '';
  foreach($attributes as $attr) {
    if(strlen($s) > 0) $s .= ' ';
    $sysinfo .= ($attr . ' = ' . $_SERVER[$attr]);
  }
  return $sysinfo;
}

/**
 * Utility function: Used for debugging the subscription function.
 * 
 */
function _phplist_debug($value, $label = 'error') {
 if(module_exists('devel') && PHPLIST_MODULE_IN_DEBUG == TRUE) {
   dpm($value, $label);  
 }
}