/core/modules/search/src/SearchQuery.php
PHP | 647 lines | 256 code | 70 blank | 321 comment | 51 complexity | 8e79aae0257397beeb9c5ade121a65ce MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.1
- <?php
- namespace Drupal\search;
- use Drupal\Core\Database\Query\Condition;
- use Drupal\Core\Database\Query\SelectExtender;
- use Drupal\Core\Database\Query\SelectInterface;
- /**
- * Search query extender and helper functions.
- *
- * Performs a query on the full-text search index for a word or words.
- *
- * This query is used by search plugins that use the search index (not all
- * search plugins do, as some use a different searching mechanism). It
- * assumes you have set up a query on the {search_index} table with alias 'i',
- * and will only work if the user is searching for at least one "positive"
- * keyword or phrase.
- *
- * For efficiency, users of this query can run the prepareAndNormalize()
- * method to figure out if there are any search results, before fully setting
- * up and calling execute() to execute the query. The scoring expressions are
- * not needed until the execute() step. However, it's not really necessary
- * to do this, because this class's execute() method does that anyway.
- *
- * During both the prepareAndNormalize() and execute() steps, there can be
- * problems. Call getStatus() to figure out if the query is OK or not.
- *
- * The query object is given the tag 'search_$type' and can be further
- * extended with hook_query_alter().
- */
- class SearchQuery extends SelectExtender {
- /**
- * Indicates no positive keywords were in the search expression.
- *
- * Positive keywords are words that are searched for, as opposed to negative
- * keywords, which are words that are excluded. To count as a keyword, a
- * word must be at least
- * \Drupal::config('search.settings')->get('index.minimum_word_size')
- * characters.
- *
- * @see SearchQuery::getStatus()
- */
- const NO_POSITIVE_KEYWORDS = 1;
- /**
- * Indicates that part of the search expression was ignored.
- *
- * To prevent Denial of Service attacks, only
- * \Drupal::config('search.settings')->get('and_or_limit') expressions
- * (positive keywords, phrases, negative keywords) are allowed; this flag
- * indicates that expressions existed past that limit and they were removed.
- *
- * @see SearchQuery::getStatus()
- */
- const EXPRESSIONS_IGNORED = 2;
- /**
- * Indicates that lower-case "or" was in the search expression.
- *
- * The word "or" in lower case was found in the search expression. This
- * probably means someone was trying to do an OR search but used lower-case
- * instead of upper-case.
- *
- * @see SearchQuery::getStatus()
- */
- const LOWER_CASE_OR = 4;
- /**
- * Indicates that no positive keyword matches were found.
- *
- * @see SearchQuery::getStatus()
- */
- const NO_KEYWORD_MATCHES = 8;
- /**
- * The keywords and advanced search options that are entered by the user.
- *
- * @var string
- */
- protected $searchExpression;
- /**
- * The type of search (search type).
- *
- * This maps to the value of the type column in search_index, and is usually
- * equal to the machine-readable name of the plugin or the search page.
- *
- * @var string
- */
- protected $type;
- /**
- * Parsed-out positive and negative search keys.
- *
- * @var array
- */
- protected $keys = ['positive' => [], 'negative' => []];
- /**
- * Indicates whether the query conditions are simple or complex (LIKE).
- *
- * @var bool
- */
- protected $simple = TRUE;
- /**
- * Conditions that are used for exact searches.
- *
- * This is always used for the second step in the query, but is not part of
- * the preparation step unless $this->simple is FALSE.
- *
- * @var Drupal\Core\Database\Query\ConditionInterface[]
- */
- protected $conditions;
- /**
- * Indicates how many matches for a search query are necessary.
- *
- * @var int
- */
- protected $matches = 0;
- /**
- * Array of positive search words.
- *
- * These words have to match against {search_index}.word.
- *
- * @var array
- */
- protected $words = [];
- /**
- * Multiplier to normalize the keyword score.
- *
- * This value is calculated by the preparation step, and is used as a
- * multiplier of the word scores to make sure they are between 0 and 1.
- *
- * @var float
- */
- protected $normalize = 0;
- /**
- * Indicates whether the preparation step has been executed.
- *
- * @var bool
- */
- protected $executedPrepare = FALSE;
- /**
- * A bitmap of status conditions, described in getStatus().
- *
- * @var int
- *
- * @see SearchQuery::getStatus()
- */
- protected $status = 0;
- /**
- * The word score expressions.
- *
- * @var array
- *
- * @see SearchQuery::addScore()
- */
- protected $scores = [];
- /**
- * Arguments for the score expressions.
- *
- * @var array
- */
- protected $scoresArguments = [];
- /**
- * The number of 'i.relevance' occurrences in score expressions.
- *
- * @var int
- */
- protected $relevance_count = 0;
- /**
- * Multipliers for score expressions.
- *
- * @var array
- */
- protected $multiply = [];
- /**
- * Sets the search query expression.
- *
- * @param string $expression
- * A search string, which can contain keywords and options.
- * @param string $type
- * The search type. This maps to {search_index}.type in the database.
- *
- * @return $this
- */
- public function searchExpression($expression, $type) {
- $this->searchExpression = $expression;
- $this->type = $type;
- // Add query tag.
- $this->addTag('search_' . $type);
- // Initialize conditions and status.
- $this->conditions = new Condition('AND');
- $this->status = 0;
- return $this;
- }
- /**
- * Parses the search query into SQL conditions.
- *
- * Sets up the following variables:
- * - $this->keys
- * - $this->words
- * - $this->conditions
- * - $this->simple
- * - $this->matches
- */
- protected function parseSearchExpression() {
- // Matches words optionally prefixed by a - sign. A word in this case is
- // something between two spaces, optionally quoted.
- preg_match_all('/ (-?)("[^"]+"|[^" ]+)/i', ' ' . $this->searchExpression, $keywords, PREG_SET_ORDER);
- if (count($keywords) == 0) {
- return;
- }
- // Classify tokens.
- $in_or = FALSE;
- $limit_combinations = \Drupal::config('search.settings')->get('and_or_limit');
- // The first search expression does not count as AND.
- $and_count = -1;
- $or_count = 0;
- foreach ($keywords as $match) {
- if ($or_count && $and_count + $or_count >= $limit_combinations) {
- // Ignore all further search expressions to prevent Denial-of-Service
- // attacks using a high number of AND/OR combinations.
- $this->status |= SearchQuery::EXPRESSIONS_IGNORED;
- break;
- }
- // Strip off phrase quotes.
- $phrase = FALSE;
- if ($match[2][0] == '"') {
- $match[2] = substr($match[2], 1, -1);
- $phrase = TRUE;
- $this->simple = FALSE;
- }
- // Simplify keyword according to indexing rules and external
- // preprocessors. Use same process as during search indexing, so it
- // will match search index.
- $words = search_simplify($match[2]);
- // Re-explode in case simplification added more words, except when
- // matching a phrase.
- $words = $phrase ? [$words] : preg_split('/ /', $words, -1, PREG_SPLIT_NO_EMPTY);
- // Negative matches.
- if ($match[1] == '-') {
- $this->keys['negative'] = array_merge($this->keys['negative'], $words);
- }
- // OR operator: instead of a single keyword, we store an array of all
- // OR'd keywords.
- elseif ($match[2] == 'OR' && count($this->keys['positive'])) {
- $last = array_pop($this->keys['positive']);
- // Starting a new OR?
- if (!is_array($last)) {
- $last = [$last];
- }
- $this->keys['positive'][] = $last;
- $in_or = TRUE;
- $or_count++;
- continue;
- }
- // AND operator: implied, so just ignore it.
- elseif ($match[2] == 'AND' || $match[2] == 'and') {
- continue;
- }
- // Plain keyword.
- else {
- if ($match[2] == 'or') {
- // Lower-case "or" instead of "OR" is a warning condition.
- $this->status |= SearchQuery::LOWER_CASE_OR;
- }
- if ($in_or) {
- // Add to last element (which is an array).
- $this->keys['positive'][count($this->keys['positive']) - 1] = array_merge($this->keys['positive'][count($this->keys['positive']) - 1], $words);
- }
- else {
- $this->keys['positive'] = array_merge($this->keys['positive'], $words);
- $and_count++;
- }
- }
- $in_or = FALSE;
- }
- // Convert keywords into SQL statements.
- $has_and = FALSE;
- $has_or = FALSE;
- // Positive matches.
- foreach ($this->keys['positive'] as $key) {
- // Group of ORed terms.
- if (is_array($key) && count($key)) {
- // If we had already found one OR, this is another one AND-ed with the
- // first, meaning it is not a simple query.
- if ($has_or) {
- $this->simple = FALSE;
- }
- $has_or = TRUE;
- $has_new_scores = FALSE;
- $queryor = new Condition('OR');
- foreach ($key as $or) {
- list($num_new_scores) = $this->parseWord($or);
- $has_new_scores |= $num_new_scores;
- $queryor->condition('d.data', "% $or %", 'LIKE');
- }
- if (count($queryor)) {
- $this->conditions->condition($queryor);
- // A group of OR keywords only needs to match once.
- $this->matches += ($has_new_scores > 0);
- }
- }
- // Single ANDed term.
- else {
- $has_and = TRUE;
- list($num_new_scores, $num_valid_words) = $this->parseWord($key);
- $this->conditions->condition('d.data', "% $key %", 'LIKE');
- if (!$num_valid_words) {
- $this->simple = FALSE;
- }
- // Each AND keyword needs to match at least once.
- $this->matches += $num_new_scores;
- }
- }
- if ($has_and && $has_or) {
- $this->simple = FALSE;
- }
- // Negative matches.
- foreach ($this->keys['negative'] as $key) {
- $this->conditions->condition('d.data', "% $key %", 'NOT LIKE');
- $this->simple = FALSE;
- }
- }
- /**
- * Parses a word or phrase for parseQuery().
- *
- * Splits a phrase into words. Adds its words to $this->words, if it is not
- * already there. Returns a list containing the number of new words found,
- * and the total number of words in the phrase.
- */
- protected function parseWord($word) {
- $num_new_scores = 0;
- $num_valid_words = 0;
- // Determine the scorewords of this word/phrase.
- $split = explode(' ', $word);
- foreach ($split as $s) {
- $num = is_numeric($s);
- if ($num || mb_strlen($s) >= \Drupal::config('search.settings')->get('index.minimum_word_size')) {
- if (!isset($this->words[$s])) {
- $this->words[$s] = $s;
- $num_new_scores++;
- }
- $num_valid_words++;
- }
- }
- // Return matching snippet and number of added words.
- return [$num_new_scores, $num_valid_words];
- }
- /**
- * Prepares the query and calculates the normalization factor.
- *
- * After the query is normalized the keywords are weighted to give the results
- * a relevancy score. The query is ready for execution after this.
- *
- * Error and warning conditions can apply. Call getStatus() after calling
- * this method to retrieve them.
- *
- * @return bool
- * TRUE if at least one keyword matched the search index; FALSE if not.
- */
- public function prepareAndNormalize() {
- $this->parseSearchExpression();
- $this->executedPrepare = TRUE;
- if (count($this->words) == 0) {
- // Although the query could proceed, there is no point in joining
- // with other tables and attempting to normalize if there are no
- // keywords present.
- $this->status |= SearchQuery::NO_POSITIVE_KEYWORDS;
- return FALSE;
- }
- // Build the basic search query: match the entered keywords.
- $or = new Condition('OR');
- foreach ($this->words as $word) {
- $or->condition('i.word', $word);
- }
- $this->condition($or);
- // Add keyword normalization information to the query.
- $this->join('search_total', 't', 'i.word = t.word');
- $this
- ->condition('i.type', $this->type)
- ->groupBy('i.type')
- ->groupBy('i.sid');
- // If the query is simple, we should have calculated the number of
- // matching words we need to find, so impose that criterion. For non-
- // simple queries, this condition could lead to incorrectly deciding not
- // to continue with the full query.
- if ($this->simple) {
- $this->having('COUNT(*) >= :matches', [':matches' => $this->matches]);
- }
- // Clone the query object to calculate normalization.
- $normalize_query = clone $this->query;
- // For complex search queries, add the LIKE conditions; if the query is
- // simple, we do not need them for normalization.
- if (!$this->simple) {
- $normalize_query->join('search_dataset', 'd', 'i.sid = d.sid AND i.type = d.type AND i.langcode = d.langcode');
- if (count($this->conditions)) {
- $normalize_query->condition($this->conditions);
- }
- }
- // Calculate normalization, which is the max of all the search scores for
- // positive keywords in the query. And note that the query could have other
- // fields added to it by the user of this extension.
- $normalize_query->addExpression('SUM(i.score * t.count)', 'calculated_score');
- $result = $normalize_query
- ->range(0, 1)
- ->orderBy('calculated_score', 'DESC')
- ->execute()
- ->fetchObject();
- if (isset($result->calculated_score)) {
- $this->normalize = (float) $result->calculated_score;
- }
- if ($this->normalize) {
- return TRUE;
- }
- // If the normalization value was zero, that indicates there were no
- // matches to the supplied positive keywords.
- $this->status |= SearchQuery::NO_KEYWORD_MATCHES;
- return FALSE;
- }
- /**
- * {@inheritdoc}
- */
- public function preExecute(SelectInterface $query = NULL) {
- if (!$this->executedPrepare) {
- $this->prepareAndNormalize();
- }
- if (!$this->normalize) {
- return FALSE;
- }
- return parent::preExecute($query);
- }
- /**
- * Adds a custom score expression to the search query.
- *
- * Score expressions are used to order search results. If no calls to
- * addScore() have taken place, a default keyword relevance score will be
- * used. However, if at least one call to addScore() has taken place, the
- * keyword relevance score is not automatically added.
- *
- * Note that you must use this method to add ordering to your searches, and
- * not call orderBy() directly, when using the SearchQuery extender. This is
- * because of the two-pass system the SearchQuery class uses to normalize
- * scores.
- *
- * @param string $score
- * The score expression, which should evaluate to a number between 0 and 1.
- * The string 'i.relevance' in a score expression will be replaced by a
- * measure of keyword relevance between 0 and 1.
- * @param array $arguments
- * Query arguments needed to provide values to the score expression.
- * @param float $multiply
- * If set, the score is multiplied with this value. However, all scores
- * with multipliers are then divided by the total of all multipliers, so
- * that overall, the normalization is maintained.
- *
- * @return $this
- */
- public function addScore($score, $arguments = [], $multiply = FALSE) {
- if ($multiply) {
- $i = count($this->multiply);
- // Modify the score expression so it is multiplied by the multiplier,
- // with a divisor to renormalize. Note that the ROUND here is necessary
- // for PostgreSQL and SQLite in order to ensure that the :multiply_* and
- // :total_* arguments are treated as a numeric type, because the
- // PostgreSQL PDO driver sometimes puts values in as strings instead of
- // numbers in complex expressions like this.
- $score = "(ROUND(:multiply_$i, 4)) * COALESCE(($score), 0) / (ROUND(:total_$i, 4))";
- // Add an argument for the multiplier. The :total_$i argument is taken
- // care of in the execute() method, which is when the total divisor is
- // calculated.
- $arguments[':multiply_' . $i] = $multiply;
- $this->multiply[] = $multiply;
- }
- // Search scoring needs a way to include a keyword relevance in the score.
- // For historical reasons, this is done by putting 'i.relevance' into the
- // search expression. So, use string replacement to change this to a
- // calculated query expression, counting the number of occurrences so
- // in the execute() method we can add arguments.
- while (($pos = strpos($score, 'i.relevance')) !== FALSE) {
- $pieces = explode('i.relevance', $score, 2);
- $score = implode('((ROUND(:normalization_' . $this->relevance_count . ', 4)) * i.score * t.count)', $pieces);
- $this->relevance_count++;
- }
- $this->scores[] = $score;
- $this->scoresArguments += $arguments;
- return $this;
- }
- /**
- * Executes the search.
- *
- * The complex conditions are applied to the query including score
- * expressions and ordering.
- *
- * Error and warning conditions can apply. Call getStatus() after calling
- * this method to retrieve them.
- *
- * @return \Drupal\Core\Database\StatementInterface|null
- * A query result set containing the results of the query.
- */
- public function execute() {
- if (!$this->preExecute($this)) {
- return NULL;
- }
- // Add conditions to the query.
- $this->join('search_dataset', 'd', 'i.sid = d.sid AND i.type = d.type AND i.langcode = d.langcode');
- if (count($this->conditions)) {
- $this->condition($this->conditions);
- }
- // Add default score (keyword relevance) if there are not any defined.
- if (empty($this->scores)) {
- $this->addScore('i.relevance');
- }
- if (count($this->multiply)) {
- // Re-normalize scores with multipliers by dividing by the total of all
- // multipliers. The expressions were altered in addScore(), so here just
- // add the arguments for the total.
- $sum = array_sum($this->multiply);
- for ($i = 0; $i < count($this->multiply); $i++) {
- $this->scoresArguments[':total_' . $i] = $sum;
- }
- }
- // Add arguments for the keyword relevance normalization number.
- $normalization = 1.0 / $this->normalize;
- for ($i = 0; $i < $this->relevance_count; $i++) {
- $this->scoresArguments[':normalization_' . $i] = $normalization;
- }
- // Add all scores together to form a query field.
- $this->addExpression('SUM(' . implode(' + ', $this->scores) . ')', 'calculated_score', $this->scoresArguments);
- // If an order has not yet been set for this query, add a default order
- // that sorts by the calculated sum of scores.
- if (count($this->getOrderBy()) == 0) {
- $this->orderBy('calculated_score', 'DESC');
- }
- // Add query metadata.
- $this
- ->addMetaData('normalize', $this->normalize)
- ->fields('i', ['type', 'sid']);
- return $this->query->execute();
- }
- /**
- * Builds the default count query for SearchQuery.
- *
- * Since SearchQuery always uses GROUP BY, we can default to a subquery. We
- * also add the same conditions as execute() because countQuery() is called
- * first.
- */
- public function countQuery() {
- if (!$this->executedPrepare) {
- $this->prepareAndNormalize();
- }
- // Clone the inner query.
- $inner = clone $this->query;
- // Add conditions to query.
- $inner->join('search_dataset', 'd', 'i.sid = d.sid AND i.type = d.type');
- if (count($this->conditions)) {
- $inner->condition($this->conditions);
- }
- // Remove existing fields and expressions, they are not needed for a count
- // query.
- $fields =& $inner->getFields();
- $fields = [];
- $expressions =& $inner->getExpressions();
- $expressions = [];
- // Add sid as the only field and count them as a subquery.
- $count = $this->connection->select($inner->fields('i', ['sid']), NULL);
- // Add the COUNT() expression.
- $count->addExpression('COUNT(*)');
- return $count;
- }
- /**
- * Returns the query status bitmap.
- *
- * @return int
- * A bitmap indicating query status. Zero indicates there were no problems.
- * A non-zero value is a combination of one or more of the following flags:
- * - SearchQuery::NO_POSITIVE_KEYWORDS
- * - SearchQuery::EXPRESSIONS_IGNORED
- * - SearchQuery::LOWER_CASE_OR
- * - SearchQuery::NO_KEYWORD_MATCHES
- */
- public function getStatus() {
- return $this->status;
- }
- }