buildFormdata

- (void)postWithAPI:(NSString *)apiString parameters:(NSDictionary *)parameters success:(void (^)(id json, JSONModelError *error))success {
    SBUser *user = [CommonHelper loadCustomObjectWithKey:kSBUSER_CURRENT_USER];
    NSString *boundary = [self generateBoundaryString];
    NSString *header = [CocoaWSSE headerWithUsername:user.userName password:user.password];

    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
    [[JSONHTTPClient requestHeaders] setValue:contentType forKey:@"Content-Type"];

    //add extra headers
    [[JSONHTTPClient requestHeaders] setValue:header forKey:@"X-WSSE"];

    NSMutableData *httpBody = [NSMutableData data];
    //make post, get requests
    [JSONHTTPClient postJSONFromURLWithString:apiString
                                       params:parameters
                                   completion:success];

    [parameters enumerateKeysAndObjectsUsingBlock:^(NSString *parameterKey, NSString *parameterValue, BOOL *stop) {
        [httpBody appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        [httpBody appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n", parameterKey] dataUsingEncoding:NSUTF8StringEncoding]];
        [httpBody appendData:[[NSString stringWithFormat:@"%@\r\n", parameterValue] dataUsingEncoding:NSUTF8StringEncoding]];
    }];

    [JSONHTTPClient postJSONFromURLWithString:apiString bodyData:httpBody completion:success];
}

- (NSString *)generateBoundaryString {
    return [NSString stringWithFormat:@"Boundary-%@", [[NSUUID UUID] UUIDString]];
}