public static function export($db, $forest_name, $fields = NULL, $tree_id = NULL)
{
// check if the table exists before doing anything else
$sql_utils = new sp_SQLUtils($db);
if (!$sql_utils->table_exists($forest_name)) {
throw new sp_Error("Table `Baobab_{$forest_name}` does not exist");
}
// get all the fields to export or check if the passed fields are valid
$tree = new Baobab($db, $forest_name, NULL);
// use a unexistent tree in the right table
if ($fields !== NULL) {
$tree->_sql_check_fields($fields);
} else {
$fields = array_keys($tree->_get_fields());
}
// remove tree_id from $fields to avoid writing it n times
// ( we give him a single property in the json format )
$idx_treeId_field = array_search("tree_id", $fields);
if (FALSE !== $idx_treeId_field) {
unset($fields[$idx_treeId_field]);
$fields = array_values($fields);
// I want to mantain a correct index sequence
}
// get the ids of the trees to export
$ar_tree_id = array();
if ($tree_id) {
if (!is_array($tree_id)) {
$tree_id = array($tree_id);
}
// ensure $tree_id contains numbers
foreach ($tree_id as $tmp_id) {
$ar_tree_id[] = intval($tmp_id);
}
} else {
$query = "SELECT DISTINCT tree_id FROM {$forest_name}";
$result = $db->query($query, MYSQLI_STORE_RESULT);
if (!$result) {
throw new sp_MySQL_Error($db);
}
while ($row = $result->fetch_row()) {
$ar_tree_id[] = intval($row[0]);
}
$result->close();
}
// get the type of the columns mainly to write numbers as ... numbers
$fieldsFlags = array();
// each index will have the field flag, to know his type
$result = $db->query("SELECT " . join(",", $fields) . " FROM {$forest_name} LIMIT 1", MYSQLI_STORE_RESULT);
if (!$result) {
throw new sp_MySQL_Error($db);
}
// retrieve the column names and their types
while ($finfo = $result->fetch_field()) {
$fieldsFlags[] = $finfo->flags;
}
$result->close();
// parse each tree and build an array to jsonize later
$ar_out = array();
foreach ($ar_tree_id as $tree_id) {
$tmp_ar = array("tree_id" => $tree_id, "fields" => $fields, "values" => null);
// retrieve the data
$tree = new Baobab($db, $forest_name, $tree_id);
$root = $tree->getTree();
if ($root !== NULL) {
$data = array(array());
// the inner array emulate a node to gain root as child
self::_traverse_tree_to_export_data($root, $data, $fieldsFlags, $tmp_ar["fields"]);
if (!empty($data[0][0])) {
$tmp_ar["values"] =& $data[0][0];
}
$ar_out[] = $tmp_ar;
}
}
return json_encode($ar_out);
}
