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Drupal example source code file (votingapi.api.php)

This example Drupal source code file (votingapi.api.php) is included in the DevDaily.com "Drupal Source Code Warehouse" project. The intent of this project is to help you "Learn Drupal by Example".

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The votingapi.api.php Drupal example source code

<?php
// $Id: votingapi.api.php,v 1.1.2.1.2.2 2010/10/09 02:33:00 eaton Exp $

/**
 * @file
 * Provides hook documentation for the VotingAPI module.
 */


/**
 * Adds to or changes the calculated vote results for a piece of content.
 *
 * VotingAPI calculates a number of common aggregate functions automatically,
 * including the average vote and total number of votes cast. Results are grouped
 * by 'tag', 'value_type', and then 'function' in the following format:
 *
 *   $results[$tag][$value_type][$aggregate_function] = $value;
 *
 * If no custom tag is being used for votes, the catch-all "vote" tag should be
 * used. In cases where custom tags are used to vote on different aspects of a
 * piece of content, a catch-all "vote" value should still be calculated for use
 * on summary screens, etc.
 *
 * @param $vote_results
 *   An alterable array of aggregate vote results.
 * @param $content_type
 *   A string identifying the type of content being rated. Node, comment,
 *   aggregator item, etc.
 * @param $content_id
 *   The key ID of the content being rated.
 *
 * @see votingapi_recalculate_results()
 */
function hook_votingapi_results_alter(&$vote_results, $content_type, $content_id) {
  // We're using a MySQLism (STDDEV isn't ANSI SQL), but it's OK because this is
  // an example. And no one would ever base real code on sample code. Ever. Never.

  $sql  = "SELECT v.tag, STDDEV(v.value) as standard_deviation ";
  $sql .= "FROM {votingapi_vote} v ";
  $sql .= "WHERE v.content_type = '%s' AND v.content_id = %d AND v.value_type = 'percent' ";
  $sql .= "GROUP BY v.tag";

  $aggregates = db_query($sql, $content_type, $content_id);

  // VotingAPI wants the data in the following format:
  // $vote_results[$tag][$value_type][$aggregate_function] = $value;

  while ($aggregate = db_fetch_array($aggregates)) {
    $vote_results[$result['tag']]['percent']['standard_deviation'] = $result['standard_deviation'];
  }
}


/**
 * Adds to or alters metadata describing Voting tags, value_types, and functions.
 *
 * If your module uses custom tags or value_types, or calculates custom aggregate
 * functions, please implement this hook so other modules can properly interperet
 * and display your data.
 *
 * Three major bins of data are stored: tags, value_types, and aggregate result
 * functions. Each entry in these bins is keyed by the value stored in the actual
 * VotingAPI tables, and contains an array with (minimally) 'name' and
 * 'description' keys. Modules can add extra keys to their entries if desired.
 *
 * @param $data
 *   An alterable array of aggregate vote results.
 *
 * @see votingapi_metadata()
 */
function hook_votingapi_metadata_alter(&$data) {
  // Document several custom tags for rating restaurants and meals.
  $data['tags']['bread'] = array(
    'name' => t('Bread'),
    'description' => t('The quality of the food at a restaurant.'),
    'module' => 'mymodule', // This is optional; we can add it for our own purposes.
  );
  $data['tags']['circuses'] = array(
    'name' => t('Circuses'),
    'description' => t('The quality of the presentation and atmosphere at a restaurant.'),
    'module' => 'mymodule',
  );

  // Document two custom aggregate function.
  $data['functions']['standard_deviation'] = array(
    'name' => t('Standard deviation'),
    'description' => t('The standard deviation of all votes cast on a given piece of content. Use this to find controversial content.'),
    'module' => 'mymodule',
  );
  $data['functions']['median'] = array(
    'name' => t('Median vote'),
    'description' => t('The median vote value cast on a given piece of content. More accurate than a pure average when there are a few outlying votes.'),
    'module' => 'mymodule',
  );
}


/**
 * Return metadata used to build Views relationships on voting data.
 *
 * VotingAPI can store votes on any entity in the Drupal database: its content_type
 * and content_id columns can be used to store "node"/1, "comment"/2, and so
 * on. This hook is used to tell VotingAPI what Views base table the content_type
 * field corresponds to, and what field in that base table contains the value in
 * votingapi's content_id table.
 *
 * @return
 *   An array of records containing 'description', 'content_type', 'base_table',
 *   and 'content_id_column' entries.
 */
function hook_votingapi_relationships() {
  $relationships[] = array(
    // 'description' is used to construct the field description in the Views UI.
    'description' => t('users'),

    // 'content_type' contain the value that your module stores in the voting
    // api 'content_type' column. 'node', 'comment', etc.
    'content_type' => 'user',

    // 'base_table' contain the name of the Views base table that stores the
    // data your votes apply to.
    'base_table' => 'user',

    // 'content_id_column' contains the name of the views field that represents
    // your base_table's primary key. This column will be joined against the
    // voting api 'content_id' column.
    'content_id_column' => 'uid',

    // VotingAPI constructs pseudo-tables so that multiple relationships can
    // point to the same base table (normal and translation-based votes nodes
    // for example. These two columns allow you to override the names of the
    // pseudo-tables. You probably don't need to change this part unless you're
    // nedjo.
    'pseudo_vote' => 'votingapi_vote_special',
    'pseudo_cache' => 'votingapi_cache_special',
  );
}

/**
 * Returns callback functions and descriptions to format a VotingAPI Views field.
 *
 * Loads all votes for a given piece of content, then calculates and caches the
 * aggregate vote results. This is only intended for modules that have assumed
 * responsibility for the full voting cycle: the votingapi_set_vote() function
 * recalculates automatically.
 *
 * @param $field
 *   A Views field object. This can be used to expose formatters only for tags,
 *   vote values, aggregate functions, etc.
 * @return
 *   An array of key-value pairs, in which each key is a callback function and
 *   each value is a human-readable description of the formatter.
 *
 * @see votingapi_set_votes()
 */
function hook_votingapi_views_formatters($field) {
  if ($field->field == 'value') {
    return array('mymodule_funky_formatter' => t('MyModule value formatter'));
  }
  if ($field->field == 'tag') {
    return array('mymodule_funky_tags' => t('MyModule tag formatter'));
  }
}

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