GroupwiseMax.php in Views (for Drupal 7) 8.3
Definition of Drupal\views\Plugin\views\relationship\GroupwiseMax.
Namespace
Drupal\views\Plugin\views\relationshipFile
lib/Drupal/views/Plugin/views/relationship/GroupwiseMax.phpView source
<?php
/**
* @file
* Definition of Drupal\views\Plugin\views\relationship\GroupwiseMax.
*/
namespace Drupal\views\Plugin\views\relationship;
use Drupal\Core\Database\Query\AlterableInterface;
use Drupal\views\ViewExecutable;
use Drupal\Core\Annotation\Plugin;
/**
* Relationship handler that allows a groupwise maximum of the linked in table.
* For a definition, see:
* http://dev.mysql.com/doc/refman/5.0/en/example-maximum-column-group-row.html
* In lay terms, instead of joining to get all matching records in the linked
* table, we get only one record, a 'representative record' picked according
* to a given criteria.
*
* Example:
* Suppose we have a term view that gives us the terms: Horse, Cat, Aardvark.
* We wish to show for each term the most recent node of that term.
* What we want is some kind of relationship from term to node.
* But a regular relationship will give us all the nodes for each term,
* giving the view multiple rows per term. What we want is just one
* representative node per term, the node that is the 'best' in some way:
* eg, the most recent, the most commented on, the first in alphabetical order.
*
* This handler gives us that kind of relationship from term to node.
* The method of choosing the 'best' implemented with a sort
* that the user selects in the relationship settings.
*
* So if we want our term view to show the most commented node for each term,
* add the relationship and in its options, pick the 'Comment count' sort.
*
* Relationship definition
* - 'outer field': The outer field to substitute into the correlated subquery.
* This must be the full field name, not the alias.
* Eg: 'term_data.tid'.
* - 'argument table',
* 'argument field': These options define a views argument that the subquery
* must add to itself to filter by the main view.
* Example: the main view shows terms, this handler is being used to get to
* the nodes base table. Your argument must be 'term_node', 'tid', as this
* is the argument that should be added to a node view to filter on terms.
*
* A note on performance:
* This relationship uses a correlated subquery, which is expensive.
* Subsequent versions of this handler could also implement the alternative way
* of doing this, with a join -- though this looks like it could be pretty messy
* to implement. This is also an expensive method, so providing both methods and
* allowing the user to choose which one works fastest for their data might be
* the best way.
* If your use of this relationship handler is likely to result in large
* data sets, you might want to consider storing statistics in a separate table,
* in the same way as node_comment_statistics.
*
* @ingroup views_relationship_handlers
*
* @Plugin(
* id = "groupwise_max"
* )
*/
class GroupwiseMax extends RelationshipPluginBase {
/**
* Defines default values for options.
*/
protected function defineOptions() {
$options = parent::defineOptions();
$options['subquery_sort'] = array(
'default' => NULL,
);
// Descending more useful.
$options['subquery_order'] = array(
'default' => 'DESC',
);
$options['subquery_regenerate'] = array(
'default' => FALSE,
'bool' => TRUE,
);
$options['subquery_view'] = array(
'default' => FALSE,
);
$options['subquery_namespace'] = array(
'default' => FALSE,
);
return $options;
}
/**
* Extends the relationship's basic options, allowing the user to pick
* a sort and an order for it.
*/
public function buildOptionsForm(&$form, &$form_state) {
parent::buildOptionsForm($form, $form_state);
// Get the sorts that apply to our base.
$sorts = views_fetch_fields($this->definition['base'], 'sort');
foreach ($sorts as $sort_id => $sort) {
$sort_options[$sort_id] = "{$sort['group']}: {$sort['title']}";
}
$base_table_data = views_fetch_data($this->definition['base']);
$form['subquery_sort'] = array(
'#type' => 'select',
'#title' => t('Representative sort criteria'),
// Provide the base field as sane default sort option.
'#default_value' => !empty($this->options['subquery_sort']) ? $this->options['subquery_sort'] : $this->definition['base'] . '.' . $base_table_data['table']['base']['field'],
'#options' => $sort_options,
'#description' => t("The sort criteria is applied to the data brought in by the relationship to determine how a representative item is obtained for each row. For example, to show the most recent node for each user, pick 'Content: Updated date'."),
);
$form['subquery_order'] = array(
'#type' => 'radios',
'#title' => t('Representative sort order'),
'#description' => t("The ordering to use for the sort criteria selected above."),
'#options' => array(
'ASC' => t('Ascending'),
'DESC' => t('Descending'),
),
'#default_value' => $this->options['subquery_order'],
);
$form['subquery_namespace'] = array(
'#type' => 'textfield',
'#title' => t('Subquery namespace'),
'#description' => t('Advanced. Enter a namespace for the subquery used by this relationship.'),
'#default_value' => $this->options['subquery_namespace'],
);
// WIP: This stuff doens't work yet: namespacing issues.
// A list of suitable views to pick one as the subview.
$views = array(
'' => '<none>',
);
$all_views = views_get_all_views();
foreach ($all_views as $view) {
// Only get views that are suitable:
// - base must the base that our relationship joins towards
// - must have fields.
if ($view->base_table == $this->definition['base'] && !empty($view->display['default']['display_options']['fields'])) {
// TODO: check the field is the correct sort?
// or let users hang themselves at this stage and check later?
if ($view->type == 'Default') {
$views[t('Default Views')][$view->storage->name] = $view->storage->name;
}
else {
$views[t('Existing Views')][$view->storage->name] = $view->storage->name;
}
}
}
$form['subquery_view'] = array(
'#type' => 'select',
'#title' => t('Representative view'),
'#default_value' => $this->options['subquery_view'],
'#options' => $views,
'#description' => t('Advanced. Use another view to generate the relationship subquery. This allows you to use filtering and more than one sort. If you pick a view here, the sort options above are ignored. Your view must have the ID of its base as its only field, and should have some kind of sorting.'),
);
$form['subquery_regenerate'] = array(
'#type' => 'checkbox',
'#title' => t('Generate subquery each time view is run.'),
'#default_value' => $this->options['subquery_regenerate'],
'#description' => t('Will re-generate the subquery for this relationship every time the view is run, instead of only when these options are saved. Use for testing if you are making changes elsewhere. WARNING: seriously impairs performance.'),
);
}
/**
* Helper function to create a pseudo view.
*
* We use this to obtain our subquery SQL.
*/
function get_temporary_view() {
$view = entity_create('view', array(
'base_table' => $this->definition['base'],
));
$view
->addDisplay('default');
return $view
->getExecutable();
}
/**
* When the form is submitted, take sure to clear the subquery string cache.
*/
public function submitOptionsForm(&$form, &$form_state) {
$cid = 'views_relationship_groupwise_max:' . $this->view->storage->name . ':' . $this->view->current_display . ':' . $this->options['id'];
cache('views_results')
->delete($cid);
}
/**
* Generate a subquery given the user options, as set in the options.
* These are passed in rather than picked up from the object because we
* generate the subquery when the options are saved, rather than when the view
* is run. This saves considerable time.
*
* @param $options
* An array of options:
* - subquery_sort: the id of a views sort.
* - subquery_order: either ASC or DESC.
* @return
* The subquery SQL string, ready for use in the main query.
*/
function left_query($options) {
// Either load another view, or create one on the fly.
if ($options['subquery_view']) {
$temp_view = views_get_view($options['subquery_view']);
// Remove all fields from default display
unset($temp_view->display['default']['display_options']['fields']);
}
else {
// Create a new view object on the fly, which we use to generate a query
// object and then get the SQL we need for the subquery.
$temp_view = $this
->get_temporary_view();
// Add the sort from the options to the default display.
// This is broken, in that the sort order field also gets added as a
// select field. See http://drupal.org/node/844910.
// We work around this further down.
$sort = $options['subquery_sort'];
list($sort_table, $sort_field) = explode('.', $sort);
$sort_options = array(
'order' => $options['subquery_order'],
);
$temp_view
->addItem('default', 'sort', $sort_table, $sort_field, $sort_options);
}
// Get the namespace string.
$temp_view->namespace = !empty($options['subquery_namespace']) ? '_' . $options['subquery_namespace'] : '_INNER';
$this->subquery_namespace = !empty($options['subquery_namespace']) ? '_' . $options['subquery_namespace'] : 'INNER';
// The value we add here does nothing, but doing this adds the right tables
// and puts in a WHERE clause with a placeholder we can grab later.
$temp_view->args[] = '**CORRELATED**';
// Add the base table ID field.
$views_data = views_fetch_data($this->definition['base']);
$base_field = $views_data['table']['base']['field'];
$temp_view
->addItem('default', 'field', $this->definition['base'], $this->definition['field']);
$relationship_id = NULL;
// Add the used relationship for the subjoin, if defined.
if (isset($this->definition['relationship'])) {
list($relationship_table, $relationship_field) = explode(':', $this->definition['relationship']);
$relationship_id = $temp_view
->addItem('default', 'relationship', $relationship_table, $relationship_field);
}
$temp_item_options = array(
'relationship' => $relationship_id,
);
// Add the correct argument for our relationship's base
// ie the 'how to get back to base' argument.
// The relationship definition tells us which one to use.
$temp_view
->addItem('default', 'argument', $this->definition['argument table'], $this->definition['argument field'], $temp_item_options);
// Build the view. The creates the query object and produces the query
// string but does not run any queries.
$temp_view
->build();
// Now take the SelectQuery object the View has built and massage it
// somewhat so we can get the SQL query from it.
$subquery = $temp_view->build_info['query'];
// Workaround until http://drupal.org/node/844910 is fixed:
// Remove all fields from the SELECT except the base id.
$fields =& $subquery
->getFields();
foreach (array_keys($fields) as $field_name) {
// The base id for this subquery is stored in our definition.
if ($field_name != $this->definition['field']) {
unset($fields[$field_name]);
}
}
// Make every alias in the subquery safe within the outer query by
// appending a namespace to it, '_inner' by default.
$tables =& $subquery
->getTables();
foreach (array_keys($tables) as $table_name) {
$tables[$table_name]['alias'] .= $this->subquery_namespace;
// Namespace the join on every table.
if (isset($tables[$table_name]['condition'])) {
$tables[$table_name]['condition'] = $this
->condition_namespace($tables[$table_name]['condition']);
}
}
// Namespace fields.
foreach (array_keys($fields) as $field_name) {
$fields[$field_name]['table'] .= $this->subquery_namespace;
$fields[$field_name]['alias'] .= $this->subquery_namespace;
}
// Namespace conditions.
$where =& $subquery
->conditions();
$this
->alter_subquery_condition($subquery, $where);
// Not sure why, but our sort order clause doesn't have a table.
// TODO: the call to add_item() above to add the sort handler is probably
// wrong -- needs attention from someone who understands it.
// In the meantime, this works, but with a leap of faith...
$orders =& $subquery
->getOrderBy();
foreach ($orders as $order_key => $order) {
// But if we're using a whole view, we don't know what we have!
if ($options['subquery_view']) {
list($sort_table, $sort_field) = explode('.', $order_key);
}
$orders[$sort_table . $this->subquery_namespace . '.' . $sort_field] = $order;
unset($orders[$order_key]);
}
// The query we get doesn't include the LIMIT, so add it here.
$subquery
->range(0, 1);
// Extract the SQL the temporary view built.
$subquery_sql = $subquery
->__toString();
// Replace the placeholder with the outer, correlated field.
// Eg, change the placeholder ':users_uid' into the outer field 'users.uid'.
// We have to work directly with the SQL, because putting a name of a field
// into a SelectQuery that it does not recognize (because it's outer) just
// makes it treat it as a string.
$outer_placeholder = ':' . str_replace('.', '_', $this->definition['outer field']);
$subquery_sql = str_replace($outer_placeholder, $this->definition['outer field'], $subquery_sql);
return $subquery_sql;
}
/**
* Recursive helper to add a namespace to conditions.
*
* Similar to _views_query_tag_alter_condition().
*
* (Though why is the condition we get in a simple query 3 levels deep???)
*/
function alter_subquery_condition(AlterableInterface $query, &$conditions) {
foreach ($conditions as $condition_id => &$condition) {
// Skip the #conjunction element.
if (is_numeric($condition_id)) {
if (is_string($condition['field'])) {
$condition['field'] = $this
->condition_namespace($condition['field']);
}
elseif (is_object($condition['field'])) {
$sub_conditions =& $condition['field']
->conditions();
$this
->alter_subquery_condition($query, $sub_conditions);
}
}
}
}
/**
* Helper function to namespace query pieces.
*
* Turns 'foo.bar' into 'foo_NAMESPACE.bar'.
*/
function condition_namespace($string) {
return str_replace('.', $this->subquery_namespace . '.', $string);
}
/**
* Called to implement a relationship in a query.
* This is mostly a copy of our parent's query() except for this bit with
* the join class.
*/
public function query() {
// Figure out what base table this relationship brings to the party.
$table_data = views_fetch_data($this->definition['base']);
$base_field = empty($this->definition['base field']) ? $table_data['table']['base']['field'] : $this->definition['base field'];
$this
->ensureMyTable();
$def = $this->definition;
$def['table'] = $this->definition['base'];
$def['field'] = $base_field;
$def['left_table'] = $this->tableAlias;
$def['left_field'] = $this->field;
$def['adjusted'] = TRUE;
if (!empty($this->options['required'])) {
$def['type'] = 'INNER';
}
if ($this->options['subquery_regenerate']) {
// For testing only, regenerate the subquery each time.
$def['left_query'] = $this
->left_query($this->options);
}
else {
// Get the stored subquery SQL string.
$cid = 'views_relationship_groupwise_max:' . $this->view->storage->name . ':' . $this->view->current_display . ':' . $this->options['id'];
$cache = cache('views_results')
->get($cid);
if (isset($cache->data)) {
$def['left_query'] = $cache->data;
}
else {
$def['left_query'] = $this
->left_query($this->options);
cache('views_results')
->set($cid, $def['left_query']);
}
}
if (!empty($def['join_id'])) {
$id = $def['join_id'];
}
else {
$id = 'subquery';
}
$join = drupal_container()
->get('plugin.manager.views.join')
->createInstance($id, $def);
// use a short alias for this:
$alias = $def['table'] . '_' . $this->table;
$this->alias = $this->query
->add_relationship($alias, $join, $this->definition['base'], $this->relationship);
}
}Classes
Name |
Description |
|---|---|
| GroupwiseMax | Relationship handler that allows a groupwise maximum of the linked in table. For a definition, see: http://dev.mysql.com/doc/refman/5.0/en/example-maximum-column-group-row.... In lay terms, instead of joining to get all matching records in the… |