Cocoa似乎没有提供此功能,只有
NSTemporaryDirectory()
可返回临时目录的路径。使用BSD mktemp
函数需要一个可变的C字符串作为参数。苹果一直在努力摆脱路径字符串,并转向使用 NSURL
。以下是一种方式:
Swift 3:
let directory = NSTemporaryDirectory()
let fileName = NSUUID().uuidString
// This returns a URL? even though it is an NSURL class method
let fullURL = NSURL.fileURL(withPathComponents: [directory, fileName])
Swift 2:
let directory = NSTemporaryDirectory()
let fileName = NSUUID().UUIDString
let fullURL = NSURL.fileURLWithPathComponents([directory, fileName])
以下是在 Swift 3 及以上版本 中使用 mkstemp()
的可能方法。使用 URL
方法可在 URL
实例与表示文件系统路径的 C 字符串之间进行转换:
// The template string:
let template = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("file.XXXXXX") as NSURL
// Fill buffer with a C string representing the local file system path.
var buffer = [Int8](repeating: 0, count: Int(PATH_MAX))
template.getFileSystemRepresentation(&buffer, maxLength: buffer.count)
// Create unique file name (and open file):
let fd = mkstemp(&buffer)
if fd != -1 {
// Create URL from file system string:
let url = URL(fileURLWithFileSystemRepresentation: buffer, isDirectory: false, relativeTo: nil)
print(url.path)
} else {
print("Error: " + String(cString: strerror(errno)))
}
Swift 2的旧代码:
// The template string:
let template = NSURL(fileURLWithPath: NSTemporaryDirectory()).URLByAppendingPathComponent("file.XXXXXX")
// Fill buffer with a C string representing the local file system path.
var buffer = [Int8](count: Int(PATH_MAX), repeatedValue: 0)
template.getFileSystemRepresentation(&buffer, maxLength: buffer.count)
// Create unique file name (and open file):
let fd = mkstemp(&buffer)
if fd != -1 {
// Create URL from file system string:
let url = NSURL(fileURLWithFileSystemRepresentation: buffer, isDirectory: false, relativeToURL: nil)
print(url.path!)
} else {
print("Error: " + String(strerror(errno)))
}
虽然NSTemporaryDirectory()
确实返回当前用户的临时目录路径,但文档中包含以下警告:
请参见
FileManager
方法url(for:in:appropriateFor:create:)
以查找正确的临时目录的首选方法。
点击链接后,会出现以下内容:
您可以使用此方法创建新的临时目录。为此,请将
directory
参数指定为FileManager.SearchPathDirectory.itemReplacementDirectory
,domain
参数指定为userDomainMask
,并指定一个URL作为url
参数,用于确定返回的URL的卷。例如,以下代码会生成一个新的临时目录,并具有类似于
/private/var/folders/d0/h37cw8ns3h1bfr_2gnwq2yyc0000gn/T/TemporaryItems/Untitled/
的路径:
let desktop = URL(fileURLWithPath: "/Users/jappleseed/Desktop/")
do {
let temporaryDirectory = try FileManager.default.url(
for: .itemReplacementDirectory,
in: .userDomainMask,
appropriateFor: desktop,
create: true
)
print(temporaryDirectory)
} catch {
// Handle the error.
}
(请注意,在创建临时目录时,create
参数将被忽略。)所以这两种方法之间到底有什么区别呢?当我从Swift REPL调用这两种不同的方法时,我得到的结果如下:1> import Foundation
2> NSTemporaryDirectory()
$R0: String = "/var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/"
3> let desktop = URL(fileURLWithPath: "/Users/chris/Desktop/")
desktop: URL = "file:///Users/chris/Desktop/"
4> let temporaryDirectory = try FileManager.default.url(
5. for: .itemReplacementDirectory,
6. in: .userDomainMask,
7. appropriateFor: desktop,
8. create: true
9. )
temporaryDirectory: URL = "file:///var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/TemporaryItems/(A%20Document%20Being%20Saved%20By%20repl_swift)/"
看起来 NSTemporaryDirectory()
总是会返回当前用户的临时目录路径,而 FileManager
的 url(for:appropriateFor:create)
方法每次调用都会返回一个新的临时子目录。例如,这里显示了从 Swift REPL 连续调用 url(for:in:appropriateFor:create:)
所返回的目录:
file:///var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/TemporaryItems/(A%20Document%20Being%20Saved%20By%20repl_swift)/
file:///var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/TemporaryItems/(A%20Document%20Being%20Saved%20By%20repl_swift%202)/
file:///var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/TemporaryItems/(A%20Document%20Being%20Saved%20By%20repl_swift%203)/
file:///var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/TemporaryItems/(A%20Document%20Being%20Saved%20By%20Xcode)/
file:///var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/TemporaryItems/(A%20Document%20Being%20Saved%20By%20Xcode%202)/
file:///var/folders/n_/0_9q7d2d1ls5v9kx599y_tj00000gn/T/TemporaryItems/(A%20Document%20Being%20Saved%20By%20Xcode%203)/
FileManager
方法 url(for:in:appropriateFor:create:)
是用于在将文件移动到更永久的位置(例如上面示例中的用户桌面)之前进行分段的,但我不明白为什么它不能被用来获取一个唯一的子目录,在你完成后会自动删除,而你不必担心其他进程写入相同临时目录时可能意外覆盖文件。受 基于UUID的Swift 2答案 的启发,这是一个Swift 3的一行代码:
let url = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString)
Swift中的文件管理器扩展,可获取临时文件URL。如有需要,可以传递自己的文件名和扩展名。
public extension FileManager {
func temporaryFileURL(fileName: String = UUID().uuidString) -> URL? {
return URL(fileURLWithPath: NSTemporaryDirectory(), isDirectory: true).appendingPathComponent(fileName)
}
}
用法:
let tempURL = FileManager.default.temporaryFileURL()
let tempJPG = FileManager.default.temporaryFileURL(fileName: "temp.jpg")
NSTemporaryDirectory()
作为临时文件夹,使用ProcessInfo.processInfo.globallyUniqueString
生成唯一字符串。func uniqueTempFolderURL() -> URL
{
let folderName = ProcessInfo.processInfo.globallyUniqueString
return URL(fileURLWithPath: NSTemporaryDirectory(), isDirectory: true).appendingPathComponent(folderName)
}
使用全球唯一标识符 (GUID):
let directory :NSString = "directory"
let randomName = NSProcessInfo().globallyUniqueString
let path = directory.stringByAppendingPathComponent(randomName)
目录/3B635E49-813A-4324-B4B8-56279B42BEAB-36687-0002D962615DAE5F
我来到这里是为了寻找类似于boost::filesystem::unique_path()的东西。
因此,我创建了这个扩展来增强URL类的功能。
extension URL {
func appendingUniquePathComponent(pathExtension: String? = nil) -> URL {
var pathComponent = UUID().uuidString
if let pathExtension = pathExtension {
pathComponent += ".\(pathExtension)"
}
return appendingPathComponent(pathComponent)
}
}
let url0 = URL(fileURLWithPath: "/tmp/some/dir")
let url1 = url0.appendingUniquePathComponent(pathExtension: "jpg")
print("url1: \(url1)")
// url1: file:///tmp/some/dir/936324FF-EEDB-410E-AD09-E24D5EB4A24F.jpg
NSTemporaryDirectory()
,这是最佳答案。 - Nike Kov只是我的个人看法,比较iOS和MacOS(沙盒)
代码:
let tmp_path1 = NSSearchPathForDirectoriesInDomains(.cachesDirectory, .userDomainMask, true).first
let tmp_path2 = NSTemporaryDirectory()
print("\n--\n", tmp_path1!, "\n", tmp_path2)
我们得到了:
> -- MacOs /Users/ingconti/Library/Containers/com.ingconti.ZipArchiveDebugAppMacOs/Data/Library/Caches
> /var/folders/40/8w6s0bsn4d55d9cjf16sjz440000gp/T/com.ingconti.ZipArchiveDebugAppMacOs/
>
>
> iOS simulator
> /Users/ingconti/Library/Developer/CoreSimulator/Devices/3AC9CBFC-5535-4213-9394-523DA82B4637/data/Containers/Data/Application/82EFDDFA-D541-4791-B76F-D754116F43C9/Library/Caches
> /Users/ingconti/Library/Developer/CoreSimulator/Devices/3AC9CBFC-5535-4213-9394-523DA82B4637/data/Containers/Data/Application/82EFDDFA-D541-4791-B76F-D754116F43C9/tmp/
>
> iOS
> /var/mobile/Containers/Data/Application/9F9EA2D1-7CCD-48B3-85C1-957FDF0D1925/Library/Caches
> /private/var/mobile/Containers/Data/Application/9F9EA2D1-7CCD-48B3-85C1-957FDF0D1925/tmp/
>
> or something similar on Your machine
let uuid = UUID().uuidString
NSTemporaryDirectory()
不是所需的内容。 - HangarRash
mkstemp
作为示例,而不是mktemp
,因为它通常更安全。 - jtbandesmkstemp
中关闭文件描述符fd
吗? - tmlenlet fh = NSFileHandle(fileDescriptor: fd, closeOnDealloc: true)
创建一个文件句柄来转移所有权。当文件句柄被释放时,fd将被关闭。 - Martin R