swift - NSURL 错误 - 文件不存在

Question

我有一个问题。

当我执行 print("Video URL:\(self.videoUrl.description)") 时，我在输出中得到了这个:

Video URL: file:///var/mobile/Containers/Data/Application/92BDA035-131C-4FD2-A176-25F77C1D295B/Documents/video.mp4

我正在使用它来将文件上传到服务器:

func uploadVideo(){
        let currentUploads = PFObject(className: "myClassOne")
        currentUploads.saveInBackgroundWithBlock({ (success: Bool, error: NSError?) -> Void in
            if error == nil{
                //**Success saving, now save video.**//

                currentUploads["userFile"] = try! PFFile(name: "video.mp4", contentsAtPath: self.videoUrl.description)
                currentUploads.saveInBackgroundWithBlock({ (success: Bool, error: NSError?) -> Void in
                    if error == nil{
                        // Take user home
                        print("Successfully uploaded")
                        })
                    }
                    else{
                        print(error, terminator: "")
                    }
                })
            }
            else{
                print(error, terminator: "")
            }
        })
    }

我收到这个错误:

fatal error: 'try!' expression unexpectedly raised an error: Error Domain=NSCocoaErrorDomain Code=4 "Failed to create PFFile at path 'file:///var/mobile/Containers/Data/Application/92BDA035-131C-4FD2-A176-25F77C1D295B/Documents/video.mp4': file does not exist." UserInfo={NSLocalizedDescription=Failed to create PFFile at path 'file:///var/mobile/Containers/Data/Application/92BDA035-131C-4FD2-A176-25F77C1D295B/Documents/video.mp4': file does not exist.}: file /Library/Caches/com.apple.xbs/Sources/swiftlang/swiftlang-703.0.18.1/src/swift/stdlib/public/core/ErrorType.swift, line 54

怎么了？为什么我从 println 成功获取到 url 后却提示“文件不存在”？有什么想法/建议吗？

Answer 1

在 try! 表达式中使用 self.videoUrl.path 而不是 self.videoUrl.description ，如下所示:

currentUploads["userFile"] = try! PFFile(name: "video.mp4", contentsAtPath: self.videoUrl.path)

(videoUrl.description 是 url 的字符串表示，开头有 "file://" 格式，使其成为无效路径。在相反，videoUrl.path 是一个以 "/var/mobile/..." 开头的字符串。)