wordpress rest api send empty json file - wordpress

Question

excuse me :: my english writing is very bad :))
I am developing a wordpress plugin and i need to get some row from custom table by rest api and excel format.
by this codes, excel file create in wordpress root and query works, but i cant download this when request address,
when request address, excell file that downloaded is empty and just writing "resourse ... " in it
please help me, thanks
add_action( 'rest_api_init', 'wpc_register_wp_api_endpoints' );
function wpc_register_wp_api_endpoints() {
register_rest_route( 'api', '/output/', array(
'methods' => 'GET',
'callback' => 'wpc_somename_search_callback',
'args' => array(
'date' => array(
'required' => true,
)
)
));
}
function wpc_somename_search_callback( $request ) {
global $wpdb;
$date = $request['date'];
$query = "SELECT * FROM {$wpdb->prefix}tickets where inroute_id=16 and date='$date'";
$list = $wpdb->get_results($query);
$jsonDecoded = json_decode( json_encode($list), true);
$fileName = 'example.csv';
$fp = fopen($fileName, 'w');
foreach($jsonDecoded as $row){
fputcsv($fp, $row);
}
fclose($fp);
header('Content-disposition: attachment; filename='.$fileName);
header('Content-type: application/json');
print $fp;
exit;
}
my request is
http://yootaabmarine.ir/wp-json/api/output/?date=13970822

Answer 1

I think that $jsonDecoded = json_decode( json_encode($list), true); is useless in your code, you are transforming an array to a JSON string and then transforming it back to an array, it is better to use $list directly.
$fp contains a resource, which is a PHP type in its own (see in the doc fopen function return type is resource), and a resource is completely different from a string, so you can't use print $fp;.
We could use readfile to correctly send a file to the browser, here is a solution:
function wpc_somename_search_callback( $request ) {
global $wpdb;
$date = $request['date'];
$query = "SELECT * FROM {$wpdb->prefix}tickets where inroute_id=16 and date='$date'";
$list = $wpdb->get_results($query);
$fileName = 'example.csv';
$fp = fopen($fileName, 'w');
foreach($list as $row){
fputcsv($fp, $row);
}
fclose($fp);
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'. $fileName .'"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($fileName));
readfile($fileName);
exit;
}
Beware of SQL injections, use prepared queries instead.