function hook_file_ranking

Provide additional methods of scoring for core search results for files.

A file's search score is used to rank it among other files matched by the search, with the highest-ranked files appearing first in the search listing.

For example, a module allowing users to vote on files could expose an option to allow search results' rankings to be influenced by the average voting score of a file.

All scoring mechanisms are provided as options to site administrators, and may be tweaked based on individual sites or disabled altogether if they do not make sense. Individual scoring mechanisms, if enabled, are assigned a weight from 1 to 10. The weight represents the factor of magnification of the ranking mechanism, with higher-weighted ranking mechanisms having more influence. In order for the weight system to work, each scoring mechanism must return a value between 0 and 1 for every file. That value is then multiplied by the administrator-assigned weight for the ranking mechanism, and then the weighted scores from all ranking mechanisms are added, which brings about the same result as a weighted average.

Return value

array: An associative array of ranking data. The keys should be strings, corresponding to the internal name of the ranking mechanism, such as 'recent', or 'usage'. The values should be arrays themselves, with the following keys available:

• "title": the human readable name of the ranking mechanism. Required.
• "join": part of a query string to join to any additional necessary table. This is not necessary if the table required is already joined to by the base query, such as for the {file_managed} table. Other tables should use the full table name as an alias to avoid naming collisions. Optional.
• "score": part of a query string to calculate the score for the ranking mechanism based on values in the database. This does not need to be wrapped in parentheses, as it will be done automatically; it also does not need to take the weighted system into account, as it will be done automatically. It does, however, need to calculate a decimal between 0 and 1; be careful not to cast the entire score to an integer by inadvertently introducing a variable argument. Required.
• "arguments": if any arguments are required for the score, they can be specified in an array here.

File

core/modules/file/file.api.php, line 379

Hooks for file module.

Code

function hook_file_ranking() {
  // If voting is disabled, we can avoid returning the array, no hard feelings.
  if (variable_get('vote_file_enabled', TRUE)) {
    return array(
      'vote_average' => array(
        'title' => t('Average vote'),
        // Note that we use i.sid, the search index's search item id, rather
        // than fm.fid.
        'join' => 'LEFT JOIN {vote_file_data} vote_file_data ON vote_file_data.fid = i.sid',
        // The highest possible score should be 1,
        // and the lowest possible score, always 0, should be 0.
        'score' => 'vote_file_data.average / CAST(%f AS DECIMAL)',
        // Pass in the highest possible voting score as a decimal argument.
        'arguments' => array(variable_get('vote_score_max', 5)),
      ),
    );
  }
}