PHP CURL syntax for WIX

I’m using Wix’s API to query products. I’ve made progress converting their examples to PHP but am stumped with their filtering method. For example, this basic query:

    curl -X POST 
   'https://www.wixapis.com/stores/v1/products/query' 
    --data-binary '{
                     "includeVariants": true
                   }' 
   -H 'Content-Type: application/json' 
   -H 'Authorization: <AUTH>'enter code here

works fine when rewritten as:

public function getProducts($code){
    $curl_postData = array(
        'includeVariants' => 'true'
    );
    $params = json_encode($curl_postData);
    $productsURL = 'https://www.wixapis.com/stores/v1/products/query';
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $productsURL);
    curl_setopt($ch, CURLOPT_HEADER, false);
    $headers = [
    'Content-Type:application/json',
    'Authorization:' . $code
    ];
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, '');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $output = curl_exec($ch);
    $curlErr = curl_error($ch);
    curl_close($ch);
    return $output;
}

But I’m having trouble filtering to a specific collection. Here’s their example:

curl 'https://www.wixapis.com/stores/v1/products/query' 
--data-binary '{
                 "query": {
                   "filter": "{"collections.id": { "$hasSome": ["32fd0b3a-2d38-2235-7754-78a3f819274a"]} }"
                 }
               }' 
-H 'Content-Type: application/json' 
-H 'Authorization: <AUTH>'

And here’s my interpretation of it ($collection is my variable to replace the fixed value in Wix’s example):

public function getProducts($code, $collection){
    $curl_postData = array(
        'filter' => array(
            'collections.id' => array(
                '$hasSome' => $collection
            )
        )
    );
    $params = json_encode($curl_postData);
    $productsURL = 'https://www.wixapis.com/stores/v1/products/query';
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $productsURL);
    curl_setopt($ch, CURLOPT_HEADER, false);
    $headers = [
    'Content-Type:application/json',
    'Authorization:' . $code
    ];
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, '');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $output = curl_exec($ch);
    $curlErr = curl_error($ch);
    curl_close($ch);
    return $output;
}   

The response is identical to the first example–I get all the products instead of just one collection. The problem is almost certainly my interpretation of their example. I think it’s meant to be a multidimensional array, but I could be reading it wrong. I’d appreciate any suggestions.

Answer

In the second code block, the value of the filter property is not an object, but a JSON-encoded object. I’m not sure why the API requires that, but it means you have to use nested json_encode() in PHP.

    $curl_postData = array(
        'filter' => json_encode(array(
            'collections.id' => array(
                '$hasSome' => $collection
            )
        ))
    );