keyword_rules.module in SEO Compliance Checker 6

Implements some keyword based rules for the SEO Checker.

File

keyword_rules/keyword_rules.module

<?php

/**
 * @file
 * Implements some keyword based rules for the SEO Checker.
 *
 */

/**
 * Implementation of hook_menu().
 * @return (array) menu items
 */
function keyword_rules_menu() {
  $items['admin/settings/seo_checker/keyword_rules'] = array(
    'title' => t('Keyword Rules'),
    'description' => t('Settings for the keyword SEO rules module.'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'keyword_rules_settings',
    ),
    'access arguments' => array(
      'administer seo_checker configuration',
    ),
    'type' => MENU_LOCAL_TASK,
    'weight' => 1,
  );
  return $items;
}

/**
 * Implementation of hook_register_seo_rules().
 * @return (array) rules
 */
function keyword_rules_register_seo_rules() {
  $rules['keyword_density'] = array(
    'name' => t('Keyword density in the body'),
    'description' => t('Checks the density of keywords over the the body of a page. Remark: too high density is not a good SEO.'),
    'threshold type' => 'range',
    'default threshold' => array(
      5,
      20,
    ),
    'callback' => 'keyword_rules_density',
    'passed feedback' => t('Test passed.'),
    'failed feedback' => t('Test failed, please make sure you use your keywords in the body but not too often.'),
  );
  $rules['keyword_in_title'] = array(
    'name' => t('Usage of keywords in node titles'),
    'description' => t('Checks if at least one of the keywords is used in the node title. If a keyword is used in the title, the result of this test indicates how early in the title the keyword appears. A threshold of 100% means that a keyword must be the first word in a node title while a threshold of 50% requires keywords to be in the first half of the node title.'),
    'threshold type' => 'at_least',
    'default threshold' => 50,
    'callback' => 'keyword_rules_title',
    'passed feedback' => t('Test passed.'),
    'failed feedback' => t('Test failed, place your keywords early in your node title.'),
  );
  $rules['keyword_in_headings'] = array(
    'name' => t('Usage of keywords in headings'),
    'description' => t('Calculates the percentage of the heading-tags (e.g. &lt;h1&gt;,&lt;h2&gt;,...) in the node body that contain keywords.'),
    'threshold type' => 'at_least',
    'default threshold' => 50,
    'callback' => 'keyword_rules_headings',
    'passed feedback' => t('Test passed.'),
    'failed feedback' => t('Test failed, use keywords in your heading-tags (e.g. &lt;h1&gt;,&lt;h2&gt;,... - Tags with lower numbers weigh more.)'),
  );
  return $rules;
}

/**
 * Dervies the densitiy of keywords within the body of the node.
 * @param object $form_values
 */
function keyword_rules_density($form_values) {
  $tags = _keyword_rules_extract_tags($form_values);
  if (count($tags) == 0) {
    return 0;
  }
  $body = strip_tags($form_values['body']);
  $words = preg_split('/\\W+/', $body);
  $total = count($words);
  $nr_of_tags = 0;
  foreach ($tags as $tag) {
    $pos = -1;
    while (($pos = seo_checker_wordipos($body, $tag, $pos + 1)) !== FALSE) {
      $nr_of_tags++;
    }
  }
  return 100 * $nr_of_tags / $total;
}

/**
 * Checks if keywords are used in the node title. If they are used, the
 * resulting score depends on how early the keywords occur in the title.
 * If a keyword is used as the first word in the title, the score will be 100%.
 * @param object $form_values
 */
function keyword_rules_title($form_values) {
  $tags = _keyword_rules_extract_tags($form_values);
  $title = strtolower($form_values['title']);
  $best_score = 1000;

  /* sentinel */
  $best_tag = null;
  foreach ($tags as $tag) {
    if (($score = seo_checker_wordipos($title, $tag)) !== FALSE && $score < $best_score) {
      $best_score = $score;
      $best_tag = $tag;
    }
  }

  /* no tags or tags not in title */
  if (is_null($best_tag)) {
    return 0;
  }

  /* calculate percentage score */
  list($before, $after) = explode($best_tag, $title, 2);
  preg_match_all('/\\W+/', $before, $matches);
  $words_before = count($matches[0]);
  if ($words_before == 0) {
    return 100;
  }
  else {
    preg_match_all('/\\W+/', $after, $matches);

    /* count the keyword itself as one oft he "words_after" */
    $words_after = count($matches[0]) + 1;
    return 100 * $words_after / ($words_before + $words_after);
  }
}
function keyword_rules_headings($form_values) {
  $tags = _keyword_rules_extract_tags($form_values);
  $body = $form_values['body'];
  if (!($nr_matches = preg_match_all('/<h(\\d)>(.*?)<\\/h\\d>/i', $body, $matches, PREG_SET_ORDER))) {
    return 100;
  }
  $good_weight = 0;
  $bad_weight = 0;
  foreach ($matches as $match) {
    $weight = $match[1];
    $heading = $match[2];
    $found = 0;
    foreach ($tags as $tag) {
      $found += intval(seo_checker_wordipos($heading, $tag) !== FALSE);
    }
    if ($found > 0) {
      $good_weight += $found / $weight;
    }
    else {
      $bad_weight += 1 / $weight;
    }
  }
  return 100 * ($good_weight / ($good_weight + $bad_weight));
}

/**
 * Helper function to extract keywords from the submitted form values.
 * @return
 *   An array of keyword tags.
 * @param object $form_values
 *   The array of form values.
 */
function _keyword_rules_extract_tags($form_values) {
  switch (variable_get('keyword_rules_keywords_driver', 'cck')) {
    case 'nodewords':
      if (function_exists('_nodewords_tag_value')) {

        # Using nodewords >= 6.x-1.12, let nodewords module do its magic...
        $keywords = _nodewords_tag_value('keywords', isset($form_values['nodewords']['metatags']) ? $form_values['nodewords']['metatags']['keywords'] : array(), array(
          'type' => NODEWORDS_TYPE_NODE,
          'id' => $form_values['nid'],
        ));
        $keywords = $keywords['value'];
      }
      else {
        $keywords = $form_values['nodewords']['keywords']['value'];
      }
      break;
    default:
      $keywords = $form_values[variable_get('keyword_rules_keywords_field', 'field_seo_keywords')][0]['value'];
      break;
  }
  return drupal_explode_tags(strtolower($keywords));
}

/**
 * Defines the settings form.
 */
function keyword_rules_settings() {
  drupal_add_js(drupal_get_path('module', 'keyword_rules') . '/js/admin.js');
  $form = array();
  $fields = array();
  $fieldarr = content_fields();
  foreach ($fieldarr as $label => $field) {
    $fields[$label] = $field['field_name'];
  }
  $keyword_field_modules = array(
    'cck' => 'cck',
  );
  if (module_exists('nodewords')) {
    $keyword_field_modules['nodewords'] = 'Meta Tags';
  }
  if (count($keyword_field_modules) > 1) {
    $form['keyword_rules_keywords_driver'] = array(
      '#type' => 'radios',
      '#title' => t('Keyword Field Provider Module'),
      '#description' => t('Select what module to use to provide a field for keywords.'),
      '#default_value' => variable_get('keyword_rules_keywords_driver', 'cck'),
      '#options' => $keyword_field_modules,
    );
  }
  else {
    $form['keyword_rules_keywords_driver'] = array(
      '#type' => 'hidden',
      '#value' => 'cck',
    );
  }
  $form['keyword_rules_cck'] = array(
    '#type' => 'fieldset',
    '#title' => t('CCK field selection'),
    '#attributes' => array(
      'id' => 'cck_settings',
      'class' => 'keyword_rule_settings_fieldset',
    ),
  );
  if (variable_get('keyword_rules_keywords_driver', 'cck') != 'cck') {
    $form['keyword_rules_cck']['#attributes']['style'] = 'display:none;';
  }
  if (count($fields) > 0) {
    $form['keyword_rules_cck']['keyword_rules_keywords_field'] = array(
      '#type' => 'select',
      '#title' => t('Field defining the keywords'),
      '#default_value' => variable_get('keyword_rules_keywords_field', 'field_seo_keywords'),
      '#description' => t('Select the field that defines the keywords to be used for the checks.'),
      '#options' => $fields,
    );
  }
  else {
    $form['keyword_rules_cck']['notice'] = array(
      '#type' => 'item',
      '#title' => t('Notice'),
      '#value' => t('There are no CCK fields that could be used to hold keywords. Please create a cck field of type text for at least one content type.'),
    );
  }
  return system_settings_form($form);
}

Functions

Name	Description
keyword_rules_density	Dervies the densitiy of keywords within the body of the node.
keyword_rules_headings
keyword_rules_menu	Implementation of hook_menu().
keyword_rules_register_seo_rules	Implementation of hook_register_seo_rules().
keyword_rules_settings	Defines the settings form.
keyword_rules_title	Checks if keywords are used in the node title. If they are used, the resulting score depends on how early the keywords occur in the title. If a keyword is used as the first word in the title, the score will be 100%.
_keyword_rules_extract_tags	Helper function to extract keywords from the submitted form values.