sodom.module

<?php 

/**
* Protects against comment form spam.
* @author benjamin birkenhake <benjamin@birkenhake.org>
*
*/

function sodom_menu() {
  $items = array();

  // Modules Settings
  $items['admin/settings/sodom'] = array(
    'title' => 'Sodom Spam Protection',
    'description' => 'Several Settings for your Sodom Spam Protection',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('sodom_admin_settings'),
    'access arguments' => array('administer sodom'),
    'menu_name' => 'Sodom',
  );
  return $items;
}

function sodom_admin_settings(){
  $form["sodom"] = array();
  
  $options = array("checkbox" => t("Checkbox"), "textfield" => t("Textfield"));
  
  $form["sodom"]["sodom_protection_type"] = array ('#type' => 'select',
      '#title' => t('Protection Type'),
      '#default_value' => variable_get('sodom_protection_type', "checkbox"),
      '#size' => 1,
      '#description' => t('Which type of Protection do you need?'),
      '#options' => $options,
  );  
  // Checkbox
  $form["sodom"]["checkbox"] = array('#type' => 'fieldset', '#title' => t('Checkbox Settings'),);
  $form["sodom"]["checkbox"]["sodom_checkbox_title"] = array ('#type' => 'textfield',
      '#title' => t('Title of the Checkbox'),
      '#default_value' => variable_get('sodom_checkbox_title', t("I am neither a Dog nor a Spambot.")),
      '#size' => 50,
      '#description' => t('The Title of your Sodom-Spam-Protection-Checkbox'),
  );
  $form["sodom"]["checkbox"]["sodom_checkbox_error"] = array ('#type' => 'textfield',
      '#title' => t('Error-Message of the Checkbox'),
      '#default_value' => variable_get('sodom_checkbox_error', t("Your Comment hasn't been saved, because you have to make a check, or are you a Dog or Spambot?!")),
      '#size' => 50,
      '#description' => t('The Error-Message of your Sodom-Spam-Protection-Checkbox'),
  );
  // Textfield
  $form["sodom"]["textfield"] = array('#type' => 'fieldset', '#title' => t('Textfield Settings'),);
  $form["sodom"]["textfield"]["sodom_textfield_question"] = array ('#type' => 'textfield',
      '#title' => t('The Question, you want to ask'),
      '#default_value' => variable_get('sodom_textfield_question', t("Are you a Dog or a Spambot? Answer with 'Yes' or 'No'")),
      '#size' => 50,
      '#description' => t('The Question of your Sodom-Spam-Protection-Textfield'),
  );
  $form["sodom"]["textfield"]["sodom_textfield_answer"] = array ('#type' => 'textfield',
      '#title' => t('The Correct Answer to your Question.'),
      '#default_value' => variable_get('sodom_textfield_answer', t("No")),
      '#size' => 50,
      '#description' => t('The Answer of your Sodom-Spam-Protection-Textfield'),
  );
  $form["sodom"]["textfield"]["sodom_textfield_error"] = array ('#type' => 'textfield',
      '#title' => t('Error-Message of the Textfield'),
      '#default_value' => variable_get('sodom_textfield_error', t("Your Comment has NOT been saved, because you have to answer the question correctly, or are you a Dog or Spambot?!")),
      '#size' => 50,
      '#description' => t('The Error-Message of your Sodom-Spam-Protection-Textfield'),
  );
  
  return system_settings_form($form);
}

function sodom_form_alter(&$form, &$form_state, $form_id){
	//dprint_r($form_state);
	global $user;
	if($form_id == "comment_form" and $user->uid==0){
	  if(variable_get('sodom_protection_type', "checkbox")=="checkbox"){
		  $form['sodom'] = array(
			  "#type" => "checkbox",
			  "#title" => variable_get('sodom_checkbox_title', t("I am neither a Dog nor a Spambot.")),
			  );
		}elseif(variable_get('sodom_protection_type', "checkbox")=="textfield"){
		  $form['sodom'] = array(
			  "#type" => "textfield",
			  "#title" => variable_get('sodom_textfield_question', t("Are you a Dog or a Spambot? Answer with 'Yes' or 'No'")),
			  );
		}
	}
}

function sodom_comment(&$a1, $op){
	global $user;
	if(variable_get('sodom_protection_type', "checkbox")=="checkbox"){
	  if($op== "validate" and $a1['sodom'] == 0 and $user->uid == 0 ){	
		  watchdog("sodom", t("Dog or Spambot Attack")."! <br/> ".t("Name").":".$a1["name"]." <br/> ".t("Comment").": ".$a1["comment"], array(), WATCHDOG_INFO);
		  form_set_error("sodom", variable_get('sodom_checkbox_error', "Your Comment has NOT been saved, because you have to make a check, or are you a Dog or Spambot?!"));
	  }
  }elseif(variable_get('sodom_protection_type', "checkbox")=="textfield"){
    if($op== "validate" and $a1['sodom'] != variable_get('sodom_textfield_answer', t("No")) and $user->uid == 0 ){	
      watchdog("sodom", t("Dog or Spambot Attack")."! <br/> ".t("Name").":".$a1["name"]." <br/> ".t("Comment").": ".$a1["comment"], array(), WATCHDOG_INFO);
		  form_set_error("sodom", variable_get('sodom_textfield_error', t("Your Comment has NOT been saved, because you have to answer the question correctly, or are you a Dog or Spambot?!")));
    }
  }
}