https://stackoverflow.com/q/54797822/1271826

UploadVideo.swift

import UIKit
import MobileCoreServices

class ViewController: UIViewController {
    let networkManager = NetworkManager()

    @IBAction func didTapButton(_ sender: Any) {
        let controller = UIImagePickerController()
        controller.mediaTypes = [kUTTypeMovie as String]
        controller.sourceType = .photoLibrary
        controller.delegate = self
        present(controller, animated: true)
    }
}

extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        networkManager.uploadFile(info[.mediaURL] as! URL)
        
        picker.dismiss(animated: true)
    }
}

class NetworkManager {
    
    let uploadURL = URL(string: "...")!
    let username = "..."
    let password = "..."

    @discardableResult
    func uploadFile(_ fileURL: URL) -> URLSessionUploadTask {
        let filename = fileURL.lastPathComponent
        let tempFile = temporaryFile(for: filename)
        
        do {
            try FileManager.default.copyItem(at: fileURL, to: tempFile)
        } catch {
            print("unable to copy file", error)
            return
        }
        
        let request = uploadRequest(for: filename)
        
        let task = URLSession.shared.uploadTask(with: request, fromFile: tempFile) { data, response, error in
            defer { try? FileManager.default.removeItem(at: tempFile) }
            
            guard let data = data,
                let httpResponse = response as? HTTPURLResponse,
                (200 ... 299) ~= httpResponse.statusCode,
                error == nil else {
                    print(error ?? "unknown error")
                    print(response ?? "no response")
                    return
            }
            
            if let json = try? JSONSerialization.jsonObject(with: data) {
                print(json)
            } else {
                print(String(data: data, encoding: .utf8) ?? data as NSData)
            }
        }
            
        task.resume()
        
        return task
    }
    
}

private extension NetworkManager {
    
    func temporaryFile(for filename: String) -> URL {
        return URL(fileURLWithPath: NSTemporaryDirectory())
            .appendingPathComponent(UUID().uuidString + "." + filename)
    }
    
    func uploadRequest(for filename: String) -> URLRequest {
        var components = URLComponents(string: uploadURL.absoluteString)!
        components.queryItems = [URLQueryItem(name: "filename", value: filename)]
        
        var request = URLRequest(url: components.url!)
        request.httpMethod = "POST"
        request.setValue(mimeType(for: filename), forHTTPHeaderField: "Content-Type")
        request.updateBasicAuth(for: username, password: password)                    // this is my own routine for setting `Authorization` header; configure your request however appropriate for your server
        
        return request
    }
    
    /// Determine mime type on the basis of extension of a file.
    ///
    /// This requires `import MobileCoreServices`.
    ///
    /// - parameter path:         The path of the file for which we are going to determine the mime type.
    ///
    /// - returns:                Returns the mime type if successful. Returns `application/octet-stream` if unable to determine mime type.
    
    private func mimeType(for path: String) -> String {
        let url = URL(fileURLWithPath: path)
        let pathExtension = url.pathExtension
        
        if let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension as NSString, nil)?.takeRetainedValue() {
            if let mimetype = UTTypeCopyPreferredTagWithClass(uti, kUTTagClassMIMEType)?.takeRetainedValue() {
                return mimetype as String
            }
        }
        return "application/octet-stream"
    }
}