Posting a nested array in PHP using cURL

Question

I have some data I need to post to an endpoint which is a nested array like:

$contentPostData = array(
            'contents' => array(
                'name' => $comment_text,
                'fingerprint' => $fingerprint,
                'signers' => array(
                    $ownerAuthId
                )
            )
        );

When I try:

json_encode($contentPostData);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

I get the error:

string(518) "{"timestamp":1578447151168,"message":"Can't read request","details":["JSON parse error: Cannot deserialize instance of `java.util.ArrayList` out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException

How do I format the contentPostData so that it can be deserialized correctly?

Answer 1

You mention:

json_encode($contentPostData);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

But are you assigning the encoded json to $data ? I mean: are you doing:

$data = json_encode($contentPostData);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

I see that the webservice to which you are calling uses com.fasterxml.jackson so most likely expects JSON format and therefore your serialization should be okay (if field names and types match).

I also suggest setting the header to inform that webservice that you are sending a json file (in case it allows other formats):

curl_setopt($ch, CURLOPT_HTTPHEADER, array(                                                                          
    'Content-Type: application/json'                                                                     
);

So:

$data = json_encode($contentPostData);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(                                                                          
    'Content-Type: application/json'                                                                       
);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

If that does not work then most likely: a) your JSON is invalid (different structure is expected) or b) the webservice actually expects a different format than JSON (maybe standard multipart data for example)