class SearchQuery
Do a query on the full-text search index for a word or words.
This function is normally only called by each module that supports the indexed search (and thus, implements hook_update_index()).
Results are retrieved in two logical passes. However, the two passes are joined together into a single query. And in the case of most simple queries the second pass is not even used.
The first pass selects a set of all possible matches, which has the benefit of also providing the exact result set for simple "AND" or "OR" searches.
The second portion of the query further refines this set by verifying advanced text conditions (such as negative or phrase matches).
The used query object has the tag 'search_$module' and can be further extended with hook_query_alter().
Hierarchy
- class \SelectQueryExtender implements SelectQueryInterface
- class \SearchQuery
Expanded class hierarchy of SearchQuery
- hook_search_execute in drupal-7.x/
modules/ search/ search.api.php - Execute a search for a set of key words.
- node_search_execute in drupal-7.x/
modules/ node/ node.module - Implements hook_search_execute().
- SearchMatchTestCase::_testQueries in drupal-7.x/
modules/ search/ search.test - Run predefine queries looking for indexed terms.
File
- drupal-7.x/
modules/ search/ search.extender.inc, line 27 - Search query extender and helper functions.
class SearchQuery extends SelectQueryExtender {
/**
* The search query that is used for searching.
*
* @var string
*/
protected $searchExpression;
/**
* Type of search (search module).
*
* This maps to the value of the type column in search_index, and is equal
* to the machine-readable name of the module that implements
* hook_search_info().
*
* @var string
*/
protected $type;
/**
* Positive and negative search keys.
*
* @var array
*/
protected $keys = array('positive' => array(), 'negative' => array());
/**
* Indicates whether the first pass query requires complex conditions (LIKE).
*
* @var boolean.
*/
protected $simple = TRUE;
/**
* Conditions that are used for exact searches.
*
* This is always used for the second pass query but not for the first pass,
* unless $this->simple is FALSE.
*
* @var DatabaseCondition
*/
protected $conditions;
/**
* Indicates how many matches for a search query are necessary.
*
* @var int
*/
protected $matches = 0;
/**
* Array of search words.
*
* These words have to match against {search_index}.word.
*
* @var array
*/
protected $words = array();
/**
* Multiplier for the normalized search score.
*
* This value is calculated by the first pass query and multiplied with the
* actual score of a specific word to make sure that the resulting calculated
* score is between 0 and 1.
*
* @var float
*/
protected $normalize;
/**
* Indicates whether the first pass query has been executed.
*
* @var boolean
*/
protected $executedFirstPass = FALSE;
/**
* Stores score expressions.
*
* @var array
*
* @see addScore()
*/
protected $scores = array();
/**
* Stores arguments for score expressions.
*
* @var array
*/
protected $scoresArguments = array();
/**
* Stores multipliers for score expressions.
*
* @var array
*/
protected $multiply = array();
/**
* Whether or not search expressions were ignored.
*
* The maximum number of AND/OR combinations exceeded can be configured to
* avoid Denial-of-Service attacks. Expressions beyond the limit are ignored.
*
* @var boolean
*/
protected $expressionsIgnored = FALSE;
/**
* Sets up the search query expression.
*
* @param $query
* A search query string, which can contain options.
* @param $module
* The search module. This maps to {search_index}.type in the database.
*
* @return
* The SearchQuery object.
*/
public function searchExpression($expression, $module) {
$this->searchExpression = $expression;
$this->type = $module;
return $this;
}
/**
* Applies a search option and removes it from the search query string.
*
* These options are in the form option:value,value2,value3.
*
* @param $option
* Name of the option.
* @param $column
* Name of the database column to which the value should be applied.
*
* @return
* TRUE if a value for that option was found, FALSE if not.
*/
public function setOption($option, $column) {
if ($values = search_expression_extract($this->searchExpression, $option)) {
$or = db_or();
foreach (explode(',', $values) as $value) {
$or->condition($column, $value);
}
$this->condition($or);
$this->searchExpression = search_expression_insert($this->searchExpression, $option);
return TRUE;
}
return FALSE;
}
/**
* Parses the search query into SQL conditions.
*
* We build two queries that match the dataset bodies.
*/
protected function parseSearchExpression() {
// Matchs words optionally prefixed by a dash. 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.
$or = FALSE;
$warning = '';
$limit_combinations = variable_get('search_and_or_limit', 7);
// 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->expressionsIgnored = TRUE;
break;
}
$phrase = FALSE;
// Strip off phrase quotes.
if ($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 = $phrase ? array($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)) {
$last = array($last);
}
$this->keys['positive'][] = $last;
$or = TRUE;
$or_count++;
continue;
}
// AND operator: implied, so just ignore it.
elseif ($match[2] == 'AND' || $match[2] == 'and') {
$warning = $match[2];
continue;
}
// Plain keyword.
else {
if ($match[2] == 'or') {
$warning = $match[2];
}
if ($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++;
}
}
$or = FALSE;
}
// Convert keywords into SQL statements.
$this->conditions = db_and();
$simple_and = FALSE;
$simple_or = FALSE;
// Positive matches.
foreach ($this->keys['positive'] as $key) {
// Group of ORed terms.
if (is_array($key) && count($key)) {
$simple_or = TRUE;
$any = FALSE;
$queryor = db_or();
foreach ($key as $or) {
list($num_new_scores) = $this->parseWord($or);
$any |= $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.
$this->matches += ($any > 0);
}
}
// Single ANDed term.
else {
$simple_and = TRUE;
list($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 += $num_new_scores;
}
}
if ($simple_and && $simple_or) {
$this->simple = FALSE;
}
// Negative matches.
foreach ($this->keys['negative'] as $key) {
$this->conditions->condition('d.data', "% $key %", 'NOT LIKE');
$this->simple = FALSE;
}
if ($warning == 'or') {
drupal_set_message(t('Search for either of the two terms with uppercase <strong>OR</strong>. For example, <strong>cats OR dogs</strong>.'));
}
}
/**
* Helper function for parseQuery().
*/
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 ($num || drupal_strlen($s) >= variable_get('minimum_word_size', 3)) {
if (!isset($this->words[$s])) {
$this->words[$s] = $s;
$num_new_scores++;
}
$num_valid_words++;
}
}
// Return matching snippet and number of added words.
return array($num_new_scores, $num_valid_words);
}
/**
* Executes the first pass query.
*
* This can either be done explicitly, so that additional scores and
* conditions can be applied to the second pass query, or implicitly by
* addScore() or execute().
*
* @return
* TRUE if search items exist, FALSE if not.
*/
public function executeFirstPass() {
$this->parseSearchExpression();
if (count($this->words) == 0) {
form_set_error('keys', format_plural(variable_get('minimum_word_size', 3), 'You must include at least one positive keyword with 1 character or more.', 'You must include at least one positive keyword with @count characters or more.'));
return FALSE;
}
if ($this->expressionsIgnored) {
drupal_set_message(t('Your search used too many AND/OR expressions. Only the first @count terms were included in this search.', array('@count' => variable_get('search_and_or_limit', 7))), 'warning');
}
$this->executedFirstPass = TRUE;
if (!empty($this->words)) {
$or = db_or();
foreach ($this->words as $word) {
$or->condition('i.word', $word);
}
$this->condition($or);
}
// Build query for keyword normalization.
$this->join('search_total', 't', 'i.word = t.word');
$this
->condition('i.type', $this->type)
->groupBy('i.type')
->groupBy('i.sid')
->having('COUNT(*) >= :matches', array(':matches' => $this->matches));
// Clone the query object to do the firstPass query;
$first = clone $this->query;
// For complex search queries, add the LIKE conditions to the first pass query.
if (!$this->simple) {
$first->join('search_dataset', 'd', 'i.sid = d.sid AND i.type = d.type');
$first->condition($this->conditions);
}
// Calculate maximum keyword relevance, to normalize it.
$first->addExpression('SUM(i.score * t.count)', 'calculated_score');
$this->normalize = $first
->range(0, 1)
->orderBy('calculated_score', 'DESC')
->execute()
->fetchField();
if ($this->normalize) {
return TRUE;
}
return FALSE;
}
/**
* 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.
*
* Also note that if you call orderBy() directly on the query, search scores
* will not automatically be used to order search results. Your orderBy()
* expression can reference 'calculated_score', which will be the total
* calculated score value.
*
* @param $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 $arguments
* Query arguments needed to provide values to the score expression.
* @param $multiply
* If set, the score is multiplied with this value. However, all scores
* with multipliers are then divided by the total of all multipliers, so
* that overall, the normalization is maintained.
*
* @return object
* The updated query object.
*/
public function addScore($score, $arguments = array(), $multiply = FALSE) {
if ($multiply) {
$i = count($this->multiply);
// Modify the score expression so it is multiplied by the multiplier,
// with a divisor to renormalize.
$score = "CAST(:multiply_$i AS DECIMAL) * COALESCE(( " . $score . "), 0) / CAST(:total_$i AS DECIMAL)";
// 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;
}
$this->scores[] = $score;
$this->scoresArguments += $arguments;
return $this;
}
/**
* Executes the search.
*
* If not already done, this executes the first pass query. Then the complex
* conditions are applied to the query including score expressions and
* ordering.
*
* @return
* FALSE if the first pass query returned no results, and a database result
* set if there were results.
*/
public function execute()
{
if (!$this->executedFirstPass) {
$this->executeFirstPass();
}
if (!$this->normalize) {
return new DatabaseStatementEmpty();
}
// Add conditions to query.
$this->join('search_dataset', 'd', 'i.sid = d.sid AND i.type = d.type');
$this->condition($this->conditions);
if (empty($this->scores)) {
// Add default score.
$this->addScore('i.relevance');
}
if (count($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.
$i = 0;
$sum = array_sum($this->multiply);
foreach ($this->multiply as $total) {
$this->scoresArguments[':total_' . $i] = $sum;
$i++;
}
}
// Replace the pseudo-expression 'i.relevance' with a measure of keyword
// relevance in all score expressions, using string replacement. Careful
// though! If you just print out a float, some locales use ',' as the
// decimal separator in PHP, while SQL always uses '.'. So, make sure to
// set the number format correctly.
$relevance = number_format((1.0 / $this->normalize), 10, '.', '');
$this->scores = str_replace('i.relevance', '(' . $relevance . ' * i.score * t.count)', $this->scores);
// 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 tag and useful metadata.
$this
->addTag('search_' . $this->type)
->addMetaData('normalize', $this->normalize)
->fields('i', array('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() {
// 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');
$inner->condition($this->conditions);
// Remove existing fields and expressions, they are not needed for a count
// query.
$fields = &$inner->getFields();
$fields = array();
$expressions = &$inner->getExpressions();
$expressions = array();
// Add the sid as the only field and count them as a subquery.
$count = db_select($inner->fields('i', array('sid')), NULL, array('target' => 'slave'));
// Add the COUNT() expression.
$count->addExpression('COUNT(*)');
return $count;
}
}
Members
Name | Modifiers | Type | Description |
---|---|---|---|
SelectQueryExtender:: |
public | function | |
SelectQueryExtender:: |
public | function | |
SelectQueryExtender:: |
public | function |
Clone magic method. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function | Magic override for undefined methods. |
SelectQueryExtender:: |
public | function |
Adds an arbitrary WHERE clause to the query. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Implements QueryPlaceholderInterface::uniqueIdentifier(). Overrides QueryPlaceholderInterface:: |
SelectQueryExtender:: |
public | function |
Add another Select query to UNION to this one. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Right Outer Join against another table in the database. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Restricts a query to a given range in the result set. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Generic preparation and validation for a SELECT query. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Orders the result set by a random value. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Orders the result set by a given field. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Sets a condition that the specified subquery returns no values. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Implements QueryPlaceholderInterface::nextPlaceholder(). Overrides QueryPlaceholderInterface:: |
SelectQueryExtender:: |
public | function |
Left Outer Join against another table in the database. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Default Join against another table in the database. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Indicates if preExecute() has already been called on that object. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
function |
Sets a condition that the specified field be NULL. Overrides QueryConditionInterface:: |
|
SelectQueryExtender:: |
function |
Sets a condition that the specified field be NOT NULL. Overrides QueryConditionInterface:: |
|
SelectQueryExtender:: |
public | function |
Inner Join against another table in the database. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function | |
SelectQueryExtender:: |
public | function |
Helper function to build most common HAVING conditional clauses. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function | |
SelectQueryExtender:: |
public | function | |
SelectQueryExtender:: |
public | function | |
SelectQueryExtender:: |
public | function |
Determines if a given query has a given tag. Overrides QueryAlterableInterface:: |
SelectQueryExtender:: |
public | function |
Determines if a given query has any specified tag. Overrides QueryAlterableInterface:: |
SelectQueryExtender:: |
public | function |
Determines if a given query has all specified tags. Overrides QueryAlterableInterface:: |
SelectQueryExtender:: |
public | function |
Groups the result set by the specified field. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Returns a reference to the union queries for this query. This include
queries for UNION, UNION ALL, and UNION DISTINCT. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Returns a reference to the tables array for this query. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Returns a reference to the order by array for this query. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Retrieves a given piece of metadata. Overrides QueryAlterableInterface:: |
SelectQueryExtender:: |
public | function |
Returns a reference to the group-by array for this query. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Returns a reference to the fields array for this query. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Returns a reference to the expressions array for this query. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Compiles and returns an associative array of the arguments for this prepared statement. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Add FOR UPDATE to the query. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Add multiple fields from the same table to be SELECTed. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Enhance this object by wrapping it in an extender object. Overrides QueryExtendableInterface:: |
SelectQueryExtender:: |
public | function |
Sets a condition that the specified subquery returns values. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Sets this query to be DISTINCT. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Gets a complete list of all conditions in this conditional clause. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Helper function: builds the most common conditional clauses. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Check whether a condition has been previously compiled. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Compiles the saved conditions for later retrieval. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Gets a complete list of all values to insert into the prepared statement. Overrides QueryConditionInterface:: |
SelectQueryExtender:: |
public | function |
Adds a tag to a query. Overrides QueryAlterableInterface:: |
SelectQueryExtender:: |
public | function |
Adds additional metadata to the query. Overrides QueryAlterableInterface:: |
SelectQueryExtender:: |
public | function |
Join against another table in the database. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Adds a field to the list to be SELECTed. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
public | function |
Adds an expression to the list of "fields" to be SELECTed. Overrides SelectQueryInterface:: |
SelectQueryExtender:: |
protected | property | A unique identifier for this query object. |
SelectQueryExtender:: |
protected | property | The SelectQuery object we are extending/decorating. |
SelectQueryExtender:: |
protected | property | The placeholder counter. |
SelectQueryExtender:: |
protected | property | The connection object on which to run this query. |
SearchQuery:: |
public | function | Applies a search option and removes it from the search query string. |
SearchQuery:: |
public | function | Sets up the search query expression. |
SearchQuery:: |
protected | function | Helper function for parseQuery(). |
SearchQuery:: |
protected | function | Parses the search query into SQL conditions. |
SearchQuery:: |
public | function | Executes the first pass query. |
SearchQuery:: |
public | function |
Executes the search. Overrides SelectQueryExtender:: |
SearchQuery:: |
public | function |
Builds the default count query for SearchQuery. Overrides SelectQueryExtender:: |
SearchQuery:: |
public | function | Adds a custom score expression to the search query. |
SearchQuery:: |
protected | property | Array of search words. |
SearchQuery:: |
protected | property | Type of search (search module). |
SearchQuery:: |
protected | property | Indicates whether the first pass query requires complex conditions (LIKE). |
SearchQuery:: |
protected | property | The search query that is used for searching. |
SearchQuery:: |
protected | property | Stores arguments for score expressions. |
SearchQuery:: |
protected | property | Stores score expressions. |
SearchQuery:: |
protected | property | Multiplier for the normalized search score. |
SearchQuery:: |
protected | property | Stores multipliers for score expressions. |
SearchQuery:: |
protected | property | Indicates how many matches for a search query are necessary. |
SearchQuery:: |
protected | property | Positive and negative search keys. |
SearchQuery:: |
protected | property | Whether or not search expressions were ignored. |
SearchQuery:: |
protected | property | Indicates whether the first pass query has been executed. |
SearchQuery:: |
protected | property | Conditions that are used for exact searches. |