"Rich media" share issue - multipart/form-data

[scottybo]

Q	A
Bug?	unsure
New Feature?	unsure
Are you using composer?	yes
Version	1

Actual Behavior

I need to upload Rich Media following the LinkedIn docs: https://developer.linkedin.com/docs/guide/v2/shares/rich-media-shares#upload

Expected Behavior

A URN response, e.g.

{
  "location": "urn:li:richMediaSummary:PNG-IMG-54f022ae8b3f4d479e925b4df68e19"
}

Actual response

array (
  'serviceErrorCode' => 0,
  'message' => 'The request is not a multipart request',
  'status' => 400,
)  

Steps to Reproduce

I'm struggling to send Multipart/form data to the LinkedIn API via Happyr. I've attempted all sorts of ways to get this to work, and here's the the last attempt before creating this issue:

$file = file_get_contents($this->post['media_url']);

$multipart = [
    [
        'name'     => 'image',
        'contents' => $file                    
    ]
];

$boundary = sha1(uniqid('', true));

$photo_options = [
    'headers' => [
        'Content-Type'=>'multipart/form-data; boundary=--'.$boundary.'--'
    ],
    'body' => new \GuzzleHttp\Psr7\MultipartStream($multipart,$boundary)
];

$photos_response = LinkedIn::post('media/upload', $photo_options);

Possible Solutions

Add support for multipart forms (or guide on how to do this properly)