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/**
* BEdita, API-first content management framework
* Copyright 2017 ChannelWeb Srl, Chialab Srl
*
* This file is part of BEdita: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* See LICENSE.LGPL or <http://gnu.org/licenses/lgpl-3.0.html> for more details.
*/
namespace BEdita\Core\Model\Behavior;
use BEdita\Core\Exception\BadFilterException;
use BEdita\Core\Model\Validation\LocationsValidator;
use Cake\Database\Expression\FunctionExpression;
use Cake\Database\Expression\QueryExpression;
use Cake\Database\Query as DatabaseQuery;
use Cake\ORM\Behavior;
use Cake\ORM\Query;
use Cake\Utility\Hash;
/**
* Behavior for geographic searches.
*
* @since 4.0.0
*/
class GeometryBehavior extends Behavior
{
/**
* @inheritDoc
*/
protected $_defaultConfig = [
'distanceFunction' => 'ST_Distance_Sphere',
'field' => 'coords',
'implementedFinders' => [
'geo' => 'findGeo',
],
];
/**
* Store geometry support for current connection.
*
* @var bool
*/
protected $hasGeoSupport;
/**
* Get database expression to find distance between two points on a spheroid.
*
* Points are expressed as pairs of floats, where the first number is the latitude,
* and the latter is the longitude.
*
* @param string|float[] $point1 First point. Can be either a field name or a pair of floats.
* @param string|float[] $point2 Second point. Can be either a field name or a pair of floats.
* @return \Cake\Database\Expression\FunctionExpression
*/
protected function getDistanceExpression($point1, $point2)
{
$point1 = is_string($point1) ? [$point1 => 'identifier'] : [sprintf('POINT (%s %s)', ...array_reverse($point1))];
$point2 = is_string($point2) ? [$point2 => 'identifier'] : [sprintf('POINT (%s %s)', ...array_reverse($point2))];
return new FunctionExpression(
$this->getConfig('distanceFunction'),
[
new FunctionExpression('ST_GeomFromText', $point1),
new FunctionExpression('ST_GeomFromText', $point2),
],
[],
'float'
);
}
/**
* Parse coordinates.
*
* Value **MUST** be either:
* - a string containing two decimal numbers separated by a comma (`,`) or a space (` `), or
* - an array containing two decimal numbers
*
* The two decimal numbers are interpreted as latitude and longitude, in this order.
* Latitude **MUST** be in the range [-90, 90], longitude in range [-180, 180]. Please note that,
* while many systems restrict longitude range to (-180, 180], here -180 is an accepted value.
*
* @param mixed $point Coordinates.
* @return float[] Latitude, longitude.
* @throws \BEdita\Core\Exception\BadFilterException Throws an exception if value could not be parsed into coords.
*/
public static function parseCoordinates($point)
{
if (empty($point)) {
throw new BadFilterException([
'title' => __d('bedita', 'Invalid data'),
'detail' => 'missing or empty coordinates',
]);
}
if (!is_array($point)) {
$point = preg_split('/[\s,]/', (string)$point, 2);
}
$point = filter_var_array(array_values($point), FILTER_VALIDATE_FLOAT);
$validationResult = LocationsValidator::checkCoordinates($point);
if ($validationResult !== true) {
throw new BadFilterException([
'title' => __d('bedita', 'Invalid data'),
'detail' => 'bad geo data format: ' . $validationResult,
]);
}
return $point;
}
/**
* Check if current DB supports geo operations.
*
* @return bool
*/
public function checkGeoSupport()
{
$connection = $this->getTable()->getConnection();
if (!isset($this->hasGeoSupport)) {
try {
$query = new DatabaseQuery($connection);
$query = $query->select([
'dist' => $this->getDistanceExpression([0, 0], [1, 1]),
]);
$query->execute();
$this->hasGeoSupport = true;
} catch (\PDOException $e) {
$this->hasGeoSupport = false;
}
}
return $this->hasGeoSupport;
}
/**
* Find objects by geo coordinates.
*
* Modify a query to filter objects using geo data: location objects are ordered by distance,
* from the nearest to the farthest from a center, optionally filtering those farther than a radius.
* Results will contain a `distance` computed field, expressing distance from that Location to the
* supplied center (or `from`, if present).
*
* **All distances are expressed in _meters_.**
*
* Accepted options are:
* - 'center' (_required_) with point coordinates, latitude and longitude
* - 'from' (_optional_, defaults to `center`) with point coordinates, latitude and longitude
* - 'radius' (_optional_, if omitted results are not filtered) with positive decimal number
*
* The three options are to be interpreted as follows:
*
* > Find all bus stops close to the Coliseum (`center`) within a range of 2km (`radius`),
* > refering how far these location are from Vatican City (`from`).
*
* ### Examples
*
* ```php
* // Find location objects near a given center, either a string with comma separated values or an array.
* $table->find('geo', ['center' => '44.4944183,11.3464055']);
* $table->find('geo', ['center' => [44.4944183, 11.3464055]]);
*
* // Find location objects within a radius of 10 kilometers from the given range.
* $table->find('geo', ['center' => [44.4944183, 11.3464055], 'radius' => 10000]);
*
* // Find location objects that are close to a center, but compute distances from another center.
* $table->find('geo', ['center' => [44.4944183, 11.3464055], 'from' => [11.3464055, 44.4944183]]);
* ```
*
* @param \Cake\ORM\Query $query Query object instance.
* @param array $options Array of acceptable geo localization conditions.
* @return \Cake\ORM\Query
* @throws \BEdita\Core\Exception\BadFilterException Throws an exception if value could not be parsed into
* valid coordinates, or if GIS SQL functions are not available.
*/
public function findGeo(Query $query, array $options)
{
$center = static::parseCoordinates(Hash::get($options, 'center'));
$distanceCenter = static::parseCoordinates(Hash::get($options, 'from', $center));
$radius = filter_var(Hash::get($options, 'radius'), FILTER_VALIDATE_FLOAT, ['options' => ['min_range' => 0]]);
$field = $this->getTable()->aliasField($this->getConfig('field'));
if (!$this->checkGeoSupport()) {
throw new BadFilterException([
'title' => __d('bedita', 'Invalid data'),
'detail' => 'operation not supported on current database',
]);
}
return $query
->select(['distance' => $this->getDistanceExpression($field, $distanceCenter)])
->enableAutoFields(true)
->where(function (QueryExpression $exp) use ($center, $field, $radius) {
if ($radius !== false) {
$exp = $exp->lte($this->getDistanceExpression($field, $center), $radius);
}
return $exp->isNotNull($field);
})
->orderAsc($this->getDistanceExpression($field, $center));
}
}