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Diffstat (limited to 'engine/lib/location.php')
| -rw-r--r-- | engine/lib/location.php | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/engine/lib/location.php b/engine/lib/location.php new file mode 100644 index 000000000..5b889509b --- /dev/null +++ b/engine/lib/location.php @@ -0,0 +1,157 @@ +<?php +/** + * Elgg geo-location tagging library. + * + * @package Elgg.Core + * @subpackage Location + */ + +/** + * Encode a location into a latitude and longitude, caching the result. + * + * Works by triggering the 'geocode' 'location' plugin + * hook, and requires a geocoding plugin to be installed. + * + * @param string $location The location, e.g. "London", or "24 Foobar Street, Gotham City" + * @return string|false + */ +function elgg_geocode_location($location) { + global $CONFIG; + + if (is_array($location)) { + return false; + } + + $location = sanitise_string($location); + + // Look for cached version + $query = "SELECT * from {$CONFIG->dbprefix}geocode_cache WHERE location='$location'"; + $cached_location = get_data_row($query); + + if ($cached_location) { + return array('lat' => $cached_location->lat, 'long' => $cached_location->long); + } + + // Trigger geocode event if not cached + $return = false; + $return = elgg_trigger_plugin_hook('geocode', 'location', array('location' => $location), $return); + + // If returned, cache and return value + if (($return) && (is_array($return))) { + $lat = (float)$return['lat']; + $long = (float)$return['long']; + + // Put into cache at the end of the page since we don't really care that much + $query = "INSERT DELAYED INTO {$CONFIG->dbprefix}geocode_cache " + . " (location, lat, `long`) VALUES ('$location', '{$lat}', '{$long}')" + . " ON DUPLICATE KEY UPDATE lat='{$lat}', `long`='{$long}'"; + execute_delayed_write_query($query); + } + + return $return; +} + +/** + * Return entities within a given geographic area. + * + * Also accepts all options available to elgg_get_entities(). + * + * @see elgg_get_entities + * + * @param array $options Array in format: + * + * latitude => FLOAT Latitude of the location + * + * longitude => FLOAT Longitude of the location + * + * distance => FLOAT/ARR ( + * latitude => float, + * longitude => float, + * ) + * The distance in degrees that determines the search box. A + * single float will result in a square in degrees. + * @warning The Earth is round. + * + * @see ElggEntity::setLatLong() + * + * @return mixed If count, int. If not count, array. false on errors. + * @since 1.8.0 + */ +function elgg_get_entities_from_location(array $options = array()) { + + global $CONFIG; + + if (!isset($options['latitude']) || !isset($options['longitude']) || + !isset($options['distance'])) { + return false; + } + + if (!is_array($options['distance'])) { + $lat_distance = (float)$options['distance']; + $long_distance = (float)$options['distance']; + } else { + $lat_distance = (float)$options['distance']['latitude']; + $long_distance = (float)$options['distance']['longitude']; + } + + $lat = (float)$options['latitude']; + $long = (float)$options['longitude']; + $lat_min = $lat - $lat_distance; + $lat_max = $lat + $lat_distance; + $long_min = $long - $long_distance; + $long_max = $long + $long_distance; + + $where = array(); + $wheres[] = "lat_name.string='geo:lat'"; + $wheres[] = "lat_value.string >= $lat_min"; + $wheres[] = "lat_value.string <= $lat_max"; + $wheres[] = "lon_name.string='geo:long'"; + $wheres[] = "lon_value.string >= $long_min"; + $wheres[] = "lon_value.string <= $long_max"; + + $joins = array(); + $joins[] = "JOIN {$CONFIG->dbprefix}metadata lat on e.guid=lat.entity_guid"; + $joins[] = "JOIN {$CONFIG->dbprefix}metastrings lat_name on lat.name_id=lat_name.id"; + $joins[] = "JOIN {$CONFIG->dbprefix}metastrings lat_value on lat.value_id=lat_value.id"; + $joins[] = "JOIN {$CONFIG->dbprefix}metadata lon on e.guid=lon.entity_guid"; + $joins[] = "JOIN {$CONFIG->dbprefix}metastrings lon_name on lon.name_id=lon_name.id"; + $joins[] = "JOIN {$CONFIG->dbprefix}metastrings lon_value on lon.value_id=lon_value.id"; + + // merge wheres to pass to get_entities() + if (isset($options['wheres']) && !is_array($options['wheres'])) { + $options['wheres'] = array($options['wheres']); + } elseif (!isset($options['wheres'])) { + $options['wheres'] = array(); + } + $options['wheres'] = array_merge($options['wheres'], $wheres); + + // merge joins to pass to get_entities() + if (isset($options['joins']) && !is_array($options['joins'])) { + $options['joins'] = array($options['joins']); + } elseif (!isset($options['joins'])) { + $options['joins'] = array(); + } + $options['joins'] = array_merge($options['joins'], $joins); + + return elgg_get_entities_from_relationship($options); +} + +/** + * Returns a viewable list of entities from location + * + * @param array $options + * + * @see elgg_list_entities() + * @see elgg_get_entities_from_location() + * + * @return string The viewable list of entities + * @since 1.8.0 + */ +function elgg_list_entities_from_location(array $options = array()) { + return elgg_list_entities($options, 'elgg_get_entities_from_location'); +} + +// Some distances in degrees (approximate) +// @todo huh? see warning on elgg_get_entities_from_location() +define("MILE", 0.01515); +define("KILOMETER", 0.00932); |