Httprequest error. Help to make the correct request - salesforce

Question

I have example request:
curl https://upload.box.com/api/2.0/files/content \
-H "Authorization: Bearer ACCESS_TOKEN" \
-F filename=#FILE_NAME \
-F parent_id=PARENT_FOLDER_ID
My request returns an error missing_parameter","name":"parent","message":"'parent' is required".
This is my request:
String boundary = String.valueOf(DateTime.now().getTime());
String body = '------------' + boundary + '\r\n';
body +='Content-Disposition: form-data; name="FileName"; FileName="' + fileBody +'"\r\n';
body+='Content-Transfer-Encoding: base64\r\n';
if ((contentType == null) || (contentType == '')){contentType = 'application/octet-stream';}
body+='Content-Type: ' + contentType + '\r\n\r\n';
body+=EncodingUtil.base64Encode(fileBody);
body +='Content-Disposition: form-data; name="Parent"; \r\n';
body+='Content-Transfer-Encoding: base64\r\n';
if ((contentType == null) || (contentType == '')){contentType = 'application/octet-stream';}
body+='Content-Type: ' + contentType + '\r\n\r\n';
body+=0;
body+='\r\n------------' + boundary + '--';
HttpRequest req = new HttpRequest();
req.setHeader('Content-Type', 'multipart/form-data; boundary=----------' + boundary);
req.setHeader('Content-Length',String.valueof(body.length()));
req.setBody(body);
req.setHeader('Authorization', 'Bearer ' + accessToken.token__c);
req.setMethod('POST');
req.setEndpoint('https://upload.box.com/api/2.0/files/content');
Http http = new Http();
HttpResponse res = http.send(req);

Answer 1

It's asking for the ID of the folder you want to upload to.
try changing this line:
body +='Content-Disposition: form-data; name="Parent"; \r\n';
to:
body +='Content-Disposition: form-data; name="parent_id"; \r\n';
EDIT: though I have to ask, why are you sending the whole file body as the file name?