Как загрузить файлы с помощью Guzzle (OAuth 2)

Я понял это сам. Вот соответствующий код (полный Controller метод), который, я надеюсь, вы найдете полезным за один день:

public function store(Request $request)
{
if ($request->hasFile('file')) {
$api = Api::latest()->take(1)->get();
$access_token = $api[0]->access_token;
if(Auth::user()->role == 'Administrator') {
$folder_id = $request->input('folder_id');
} elseif(Auth::user()->role == 'Subscriber') {
$folder_id = Auth::user()->folder_id;
}
$client = new Client();
$apiRequest = $client->post('https://upload.box.com/api/2.0/files/content');
$apiRequest->setHeaders([
'Authorization' => 'Bearer ' . $access_token,
'Content-Type' => 'multipart/form-data'
]);
$apiRequest->setPostField('filename', $request->file('file')->getClientOriginalName());
$apiRequest->setPostField('parent_id', $folder_id);
$apiRequest->addPostFile(
'file', $request->file('file')->getRealPath(),
$request->file('file')->getClientMimeType(),
$request->file('file')->getClientOriginalName()
);
try {
$sendRequest = $apiRequest->send();
if ($sendRequest->isSuccessful()) {
return redirect()->back()->with('fileUpload', trans('Your file has been uploaded successfully'));
}
} catch (BadResponseException $e) {
$result = $e->getResponse()->getStatusCode();
if ($result === 401) {
$this->regenerate_access_token();
$api = Api::latest()->take(1)->get();
$access_token = $api[0]->access_token;
$client = new Client();
$apiRequest = $client->post('https://upload.box.com/api/2.0/files/content');
$apiRequest->setHeaders([
'Authorization' => 'Bearer ' . $access_token,
'Content-Type' => 'multipart/form-data'
]);
$apiRequest->setPostField('filename', $request->file('file')->getClientOriginalName());
$apiRequest->setPostField('parent_id', Auth::user()->folder_id);
$apiRequest->addPostFile(
'file', $request->file('file')->getRealPath(),
$request->file('file')->getClientMimeType(),
$request->file('file')->getClientOriginalName()
);
$sendRequest = $apiRequest->send();
if ($sendRequest->isSuccessful()) {
return redirect()->back()->with('fileUpload', trans('Your file has been uploaded successfully'));
}
} elseif ($result === 409) {
return redirect()->back()->with('fileUpload', trans('You have already a file with the same name. Please, rename your file to successful upload'));
}
}
} else {
return redirect()->back()->with('fileUpload', trans('Please, select a file to upload'));
}
}

Вот форма загрузки файла, которая должна быть в вашем view каталог:

<form action="/store" method="post" enctype="multipart/form-data">
{{ csrf_field() }}

<div class="row">
@can('viewElements', \Illuminate\Support\Facades\Auth::user())
<div class="input-field col s3">
<select name="folder_id" id="folder_id">
<option value="" disabled selected>Choose User</option>
@foreach($users as $user)
<option value="{{ $user->folder_id }}">{{ $user->name }}</option>
@endforeach
</select>
</div>
@endcan

<div class="col {{ $class }}">
<div class="file-field input-field">
<div class="btn">
<span>File</span>
<input type="file" name="file" required>
</div>

<div class="file-path-wrapper">
<input type="text" class="file-path validate" placeholder="Upload your file">
</div>
</div>
</div>
<div class="col s3">
<button class="btn waves-effect waves-light" type="submit">Submit <i class="material-icons right">send</i></button>
</div>
</div>
</form>