objective-c 如何使用 Cocoa 创建临时文件？
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How do I create a temporary file with Cocoa?
提问by lfalin
Years ago when I was working with C# I could easily create a temporary file and get its name with this function:
多年前，当我使用 C# 时，我可以轻松地创建一个临时文件并使用此函数获取其名称：
Path.GetTempFileName();
This function would create a file with a unique name in the temporary directory and return the full path to that file.
此函数将在临时目录中创建一个具有唯一名称的文件，并返回该文件的完整路径。
In the Cocoa API's, the closest thing I can find is:
在 Cocoa API 中，我能找到的最接近的是：
NSTemporaryDirectory
Am I missing something obvious or is there no built in way to do this?
我是否遗漏了一些明显的东西，或者没有内置的方法来做到这一点？
采纳答案by lfalin
A safe way is to use mkstemp(3).
一种安全的方法是使用mkstemp(3)。
回答by Ben Gottlieb
[Note: This applies to the iPhone SDK, not the Mac OS SDK]
[注意：这适用于 iPhone SDK，不适用于 Mac OS SDK]
From what I can tell, these functions aren't present in the SDK (the unistd.hfile is drastically pared down when compared to the standard Mac OS X 10.5 file). I would use something along the lines of:
据我所知，这些功能不存在于 SDK 中（unistd.h与标准 Mac OS X 10.5 文件相比，该文件被大幅缩减）。我会使用以下内容：
[NSTemporaryDirectory() stringByAppendingPathComponent: [NSString stringWithFormat: @"%.0f.%@", [NSDate timeIntervalSinceReferenceDate] * 1000.0, @"txt"]];
Not the prettiest, but functional
不是最漂亮，但功能强大
回答by muzz
Apple has provided an excellent way for accessing temp directory and creating unique names for the temp files.
Apple 提供了一种极好的方法来访问临时目录并为临时文件创建唯一名称。
- (NSString *)pathForTemporaryFileWithPrefix:(NSString *)prefix
{
NSString * result;
CFUUIDRef uuid;
CFStringRef uuidStr;
uuid = CFUUIDCreate(NULL);
assert(uuid != NULL);
uuidStr = CFUUIDCreateString(NULL, uuid);
assert(uuidStr != NULL);
result = [NSTemporaryDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:@"%@-%@", prefix, uuidStr]];
assert(result != nil);
CFRelease(uuidStr);
CFRelease(uuid);
return result;
}
LINK :::: http://developer.apple.com/library/ios/#samplecode/SimpleURLConnections/Introduction/Intro.html#//apple_ref/doc/uid/DTS40009245see file :::AppDelegate.m
链接 :::: http://developer.apple.com/library/ios/#samplecode/SimpleURLConnections/Introduction/Intro.html#//apple_ref/doc/uid/DTS40009245见文件 :::AppDelegate.m
回答by Quinn Taylor
Though it's nearly a year later, I figured it's still helpful to mention a blog post from Cocoa With Love by Matt Gallagher. http://cocoawithlove.com/2009/07/temporary-files-and-folders-in-cocoa.htmlHe shows how to use mkstemp()for files and mkdtemp()for directories, complete with NSString conversions.
尽管已经过去了将近一年，但我认为提及 Matt Gallagher 撰写的 Cocoa With Love 的博客文章仍然很有帮助。http://cocoawithlove.com/2009/07/temporary-files-and-folders-in-cocoa.html他展示了如何使用mkstemp()文件和mkdtemp()目录，完成 NSString 转换。
回答by Philipp
I created a pure Cocoa solution by way of a category on NSFileManagerthat uses a combination of NSTemporary()and a globally unique ID.
我通过NSFileManager使用NSTemporary()和 全局唯一 ID的组合创建了一个纯 Cocoa 解决方案。
Here the header file:
这里的头文件：
@interface NSFileManager (TemporaryDirectory)
-(NSString *) createTemporaryDirectory;
@end
And the implementation file:
和实现文件：
@implementation NSFileManager (TemporaryDirectory)
-(NSString *) createTemporaryDirectory {
// Create a unique directory in the system temporary directory
NSString *guid = [[NSProcessInfo processInfo] globallyUniqueString];
NSString *path = [NSTemporaryDirectory() stringByAppendingPathComponent:guid];
if (![self createDirectoryAtPath:path withIntermediateDirectories:NO attributes:nil error:nil]) {
return nil;
}
return path;
}
@end
This creates a temporary directory but could be easily adapted to use createFileAtPath:contents:attributes:instead of createDirectoryAtPath:to create a file instead.
这会创建一个临时目录，但可以很容易地适应使用createFileAtPath:contents:attributes:而不是createDirectoryAtPath:创建文件。
回答by fzwo
If targeting iOS 6.0 or Mac OS X 10.8 or higher:
如果面向 iOS 6.0 或 Mac OS X 10.8 或更高版本：
NSString *tempFilePath = [NSTemporaryDirectory() stringByAppendingPathComponent:[[NSUUID UUID] UUIDString]];
回答by Bart van Kuik
Swift 5 and Swift 4.2
Swift 5 和 Swift 4.2
import Foundation
func pathForTemporaryFile(with prefix: String) -> URL {
let uuid = UUID().uuidString
let pathComponent = "\(prefix)-\(uuid)"
var tempPath = URL(fileURLWithPath: NSTemporaryDirectory())
tempPath.appendPathComponent(pathComponent)
return tempPath
}
let url = pathForTemporaryFile(with: "blah")
print(url)
// file:///var/folders/42/fg3l5j123z6668cgt81dhks80000gn/T/johndoe.KillerApp/blah-E1DCE512-AC4B-4EAB-8838-547C0502E264
Or alternatively Ssswift's oneliner:
或者 Ssswift 的 oneliner：
let prefix = "blah"
let url2 = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("\(prefix)-\(UUID())")
print(url2)
回答by Ssswift
The modern way to do this is FileManager's url(for:in:appropriateFor:create:).
执行此操作的现代方法是FileManager's url(for:in:appropriateFor:create:)。
With this method, you can specify a SearchPathDirectoryto say exactly what kind of temporary directory you want. For example, a .cachesDirectorywill persist between runs (as possible) and be saved in the user's library, while a .itemReplacementDirectorywill be on the same volume as the target file.
使用此方法，您可以指定 aSearchPathDirectory来准确说明您想要什么样的临时目录。例如， a.cachesDirectory将在运行之间（尽可能）持续存在并保存在用户的库中，而 a.itemReplacementDirectory将与目标文件位于同一卷上。
回答by alextgordon
You could use an NSTaskto uuidgento get a unique file name, then append that to a string from NSTemporaryDirectory(). This won't work on Cocoa Touch. It is a bit long-winded though.
您可以使用NSTasktouuidgen来获取唯一的文件名，然后将其附加到来自NSTemporaryDirectory(). 这不适用于 Cocoa Touch。不过有点啰嗦。
