UIImagePickerController+Rx.swift

extension Reactive where Base: UIImagePickerController {
    static func createAndPresent(from parent: UIViewController?, animated: Bool = true, configureImagePicker: @escaping (UIImagePickerController) throws -> Void = { x in }) -> Observable<[UIImagePickerController.InfoKey: Any]> {
        return Observable.create { [weak parent] observer in
            let imagePicker = UIImagePickerController()
            let dismissDisposable = imagePicker.rx
                .didCancel
                .subscribe(onNext: { [weak imagePicker] _ in
                    guard let imagePicker = imagePicker else {
                        return
                    }
                    dismissViewController(imagePicker, animated: animated)
                })
            let eventDisposable = imagePicker.rx.didFinishPickingMediaWithInfo
                .subscribe(onNext: { [weak imagePicker] info in
                    guard let imagePicker = imagePicker else {
                        return
                    }
                    observer.on(.next(info))
                    dismissViewController(imagePicker, animated: animated)
                })

            do {
                try configureImagePicker(imagePicker)
            } catch {
                observer.on(.error(error))
                return Disposables.create()
            }

            guard let parent = parent else {
                observer.on(.completed)
                return Disposables.create()
            }

            parent.present(imagePicker, animated: animated, completion: nil)

            return Disposables.create(dismissDisposable, eventDisposable, Disposables.create {
                    dismissViewController(imagePicker, animated: animated)
                })
        }
    }
}


let movieType = kUTTypeMovie as String
guard UIImagePickerController.isSourceTypeAvailable(.camera),
    let availableMediaTypes = UIImagePickerController.availableMediaTypes(for: .camera),
    availableMediaTypes.contains(movieType) else {
    return
}
let recordMovie = UIImagePickerController.rx.createAndPresent(from: self, animated: true) { (picker) in
    picker.sourceType = .camera
    picker.mediaTypes = [movieType]
    picker.allowsEditing = true
    picker.videoMaximumDuration = 60 // 上限60秒
    picker.videoQuality = .typeHigh
}

recordMovie
    .flatMap { info -> Observable<URL> in
        if let phAsset = info[.phAsset] as? PHAsset {
            let fileURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("/copied.mp4")
            let imageManager = PHImageManager.default()
            return imageManager.rx.requestAsset(asset: phAsset)
                .flatMap { asset -> Observable<URL> in
                    switch asset {
                    case let .movie(movieAsset):
                        return MovieService().saveAsMp4(movieAsset, nil, saveTo: fileURL)
                            .map { _ in fileURL }
                            .asObservable()
                    case .image:
                        return .empty()
                    }
                }
        } else if let url = info[.mediaURL] as? URL {
            return .just(url)
        }
        // error
        return .empty()
    }