如何检测视频网址并从网址下载不以“.mp4”结尾的视频？

Question

我需要检测网址中的视频。我知道如何直接从视频网址下载视频。但是，我需要下载视频间接网址。例如，我点击了任何youtube视频链接，然后我想检测直接视频网址并从此页面上的直接视频网址下载。 换句话说，如何在网页上找到“.mp4”扩展链接？这是我使用的代码，但只有当url以“.mp4”

结尾时才有效

@IBAction func downloadButtonAction(_ sender: Any) {
    let urlString = "https://example.com/sample.mp4"
    downloadVideoLinkAndCreateAsset(urlString)

}



func downloadVideoLinkAndCreateAsset(_ videoLink: String) {

    // use guard to make sure you have a valid url
    guard let videoURL = URL(string: videoLink) else { return }

    guard let documentsDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return }

    // check if the file already exist at the destination folder if you don't want to download it twice
    if !FileManager.default.fileExists(atPath: documentsDirectoryURL.appendingPathComponent(videoURL.lastPathComponent).path) {

        // set up your download task
        URLSession.shared.downloadTask(with: videoURL) { (location, response, error) -> Void in

            // use guard to unwrap your optional url
            guard let location = location else { return }

            // create a deatination url with the server response suggested file name
            let destinationURL = documentsDirectoryURL.appendingPathComponent(response?.suggestedFilename ?? videoURL.lastPathComponent)

            do {

                try FileManager.default.moveItem(at: location, to: destinationURL)

                PHPhotoLibrary.requestAuthorization({ (authorizationStatus: PHAuthorizationStatus) -> Void in

                    // check if user authorized access photos for your app
                    if authorizationStatus == .authorized {
                        PHPhotoLibrary.shared().performChanges({
                            PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: destinationURL)}) { completed, error in
                                if completed {
                                    print("Video asset created")
                                } else {
                                    print(error as Any)
                                }
                        }
                    }
                })

            } catch { print(error) }

            }.resume()

    } else {
        print("File already exists at destination url")
    }

}