小编Rob*_*hen的帖子

我的项目要求我下载 .pdf 文件，将其保存在 iPad 本地，然后制作电子邮件并发送。看起来很直接。

这是执行下载的代码：

    func downloadFile() {

        let urlString = <private url>
        let url = URL(string: urlString)!

        
        let downloadTask = URLSession.shared.downloadTask(with: url) {
            urlOrNil, responseOrNil, errorOrNil in
            // check for and handle errors:
            // * errorOrNil should be nil
            // * responseOrNil should be an HTTPURLResponse with statusCode in 200..<299

            guard let fileURL = urlOrNil else { return }
            do {
                let documentsURL = try
                    FileManager.default.url(for: .documentDirectory,
                                            in: .userDomainMask,
                                            appropriateFor: nil,
                                            create: false)
                let savedURL = documentsURL.appendingPathComponent(url.lastPathComponent)
                
                try? …