modules/fcf/fcf.module

<?php

// implementation of hook_menu
function fcf_menu($may_cache) {
  $items = array();

  if ($may_cache) {
    $items[] = array(
      'path' => 'admin/settings/fcf',
      'title' => t('First Click Free'),
      'description' => t('Configure First Click Free role.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('fcf_settings'));
  }
  return $items;
} 


// implementation of hook_init
function fcf_init() {
  global $user;
  /* if user is anonymous and we are coming from Google, add to $user a special role
     to let him see the article.
     Parse referrer to check if click comes from Google.
     As per http://tinyurl.com/2jtwoc, check http://*.google.*
  */ 
  $components = parse_url($_SERVER['HTTP_REFERER']); // subdomain.google.com
  $host = $components['host'];
  list($tld, $domain, $subdomain) = array_reverse(explode('.', $host)); // (com, google, subdomain)
  
  if(variable_get('fcf_debug', 0) || $user->uid == 0 && $domain == "google" ) {
    // fetch special role using rid from settings. default to 1 = anonymous user rid
    $role = db_fetch_object(db_query('SELECT * FROM {role} WHERE rid = %s', variable_get('fcf_rid', 1)));
    if($role) { // should be always true, but we check nevertheless to avoid errors
      $user->roles[$role->rid] = $role->name;
      // if we are in debug mode, show an informative message
      if(variable_get('fcf_debug', 0)) {
        $message = t("First Click Free debug mode activated. You may toggle debug mode on !link.", array("!link" => l(t("First Click Free settings"), "admin/settings/fcf")));
      }
      else {
        $message = t("Customize the message displayed to users when referred by Google. It's useful for helping or instructing them to register if they wish.");
      }
      drupal_set_message($message, "fcf");
    }
  }
}

// settings form (called from _menu)
function fcf_settings() {
  $roles = user_roles(TRUE); // first argument TRUE excludes anonymous role from listing 
  $form['fcf_rid'] = array(
      '#type' => 'select',
      '#title' => t('Extra for First Click Free users'),
      '#default_value' => variable_get('fcf_rid', 1),
      '#options' => $roles,
    );
  $form['fcf_debug'] = array(
      '#type' => 'checkbox',
      '#title' => t('Enable debug mode.'),
      '#default_value' => variable_get('fcf_debug', 0),
    );
  return system_settings_form($form);
}

1	<?php
2
3	// implementation of hook_menu
4	function fcf_menu($may_cache) {
5	$items = array();
6
7	if ($may_cache) {
8	$items[] = array(
9	'path' => 'admin/settings/fcf',
10	'title' => t('First Click Free'),
11	'description' => t('Configure First Click Free role.'),
12	'callback' => 'drupal_get_form',
13	'callback arguments' => array('fcf_settings'));
14	}
15	return $items;
16	}
17
18
19	// implementation of hook_init
20	function fcf_init() {
21	global $user;
22	/* if user is anonymous and we are coming from Google, add to $user a special role
23	to let him see the article.
24	Parse referrer to check if click comes from Google.
25	As per http://tinyurl.com/2jtwoc, check http://.google.
26	*/
27	$components = parse_url($_SERVER['HTTP_REFERER']); // subdomain.google.com
28	$host = $components['host'];
29	list($tld, $domain, $subdomain) = array_reverse(explode('.', $host)); // (com, google, subdomain)
30
31	if(variable_get('fcf_debug', 0) \|\| $user->uid == 0 && $domain == "google" ) {
32	// fetch special role using rid from settings. default to 1 = anonymous user rid
33	$role = db_fetch_object(db_query('SELECT * FROM {role} WHERE rid = %s', variable_get('fcf_rid', 1)));
34	if($role) { // should be always true, but we check nevertheless to avoid errors
35	$user->roles[$role->rid] = $role->name;
36	// if we are in debug mode, show an informative message
37	if(variable_get('fcf_debug', 0)) {
38	$message = t("First Click Free debug mode activated. You may toggle debug mode on !link.", array("!link" => l(t("First Click Free settings"), "admin/settings/fcf")));
39	}
40	else {
41	$message = t("Customize the message displayed to users when referred by Google. It's useful for helping or instructing them to register if they wish.");
42	}
43	drupal_set_message($message, "fcf");
44	}
45	}
46	}
47
48	// settings form (called from _menu)
49	function fcf_settings() {
50	$roles = user_roles(TRUE); // first argument TRUE excludes anonymous role from listing
51	$form['fcf_rid'] = array(
52	'#type' => 'select',
53	'#title' => t('Extra for First Click Free users'),
54	'#default_value' => variable_get('fcf_rid', 1),
55	'#options' => $roles,
56	);
57	$form['fcf_debug'] = array(
58	'#type' => 'checkbox',
59	'#title' => t('Enable debug mode.'),
60	'#default_value' => variable_get('fcf_debug', 0),
61	);
62	return system_settings_form($form);
63	}
64