URLRequestBuilder-4.swift

class APIClient {
    
    // Rest of code
    
    func buildURLRequest<T: APIRequest>(for request: T) throws -> URLRequest {
        do {
            var urlRequest = URLRequest(url: request.baseURL.appendingPathComponent(request.path),
                                        cachePolicy: .reloadIgnoringLocalAndRemoteCacheData,
                                        timeoutInterval: 100)
            urlRequest.httpMethod = request.method.rawValue

            request.headers?.forEach {
                urlRequest.addValue($0.value as! String, forHTTPHeaderField: $0.key)
            }

            urlRequest = try buildRequestParams(urlRequest, params: request.parameters)

            return urlRequest
        } catch {
            throw APIError.requestBuilderFailed
        }
    }

    fileprivate func buildRequestParams(_ urlRequest: URLRequest, params: RequestParams) throws -> URLRequest {
        var urlRequest = urlRequest
        urlRequest = try params.encoder.encode(urlRequest,
                                               with: params.parameters)
        return urlRequest
    }
}