Variable in a Collection request

[zane-shus]

This is not a feature request of a bug. My a lack of skill issue.

I have a laravel API app, and its meant to take a GET ID and use that in a match to get the individual item from Mongo. All my static queries are working ok.

My code is:

 $value = (int)$sub_responseItem['value'];
 $page = Track::raw(function ($collection) {
      return $collection->aggregate(
       [['$match' => ['my_id' => $value ]]]
                                            );
                                        });
    $response = new MyCollection($page);

My error is:

message": "Undefined variable $value",
    "exception": "ErrorException",
    "file": "/var/www/html/app/Http/Controllers/api/v1/MyController.php",
    "line": 79,  (this is the line with $value on it)

If I change this [['$match' => ['my_id' => $value ]]] to this [['$match' => ['my_id' => 1 ]]], it works ok.

And if i do a var_dump($value); I get (int)1

Can anyone see what I am doing wrong?

[alcaeus]

Closures don't automatically capture the current scope, so you have two ways of fixing this. If using a long closure, make sure to bind any variables used within the closure with the use keyword:

$page = Track::raw(
    function ($collection) use ($value) {
        return $collection->aggregate([['$match' => ['my_id' => $value ]]]);
    }
);

Alternatively, use a short closure which automatically captures the local scope:

$page = Track::raw(
    fn ($collection) => 
        $collection->aggregate([['$match' => ['my_id' => $value ]]])
);

I'll assume that you changed the code for brevity in this issue, but for the sake of completeness I'll mention that the query you're running neither requires an aggregate command, nor does it need to run through raw. Instead, you can query for this directly:

$page = Track::find('my_id', $value)->first();

[zane-shus]

that was it, thank you.. your a champion..

I guess its a related question.. What is a long vs short closure? My google foo let me down in searching (I used short from the above).

[alcaeus]

The correct name for the feature would be Arrow Function, which is a more concise syntax for anonymous functions introduced in PHP 7.4.

[zane-shus]

this helped.. thank you