Is there a safer way to create a directory if it does not exist?
IosObjective CFilesystemsNsfilemanagerNsdocumentdirectoryIos Problem Overview
I've found this way of creating a directory if it does not exist. But it looks a bit wonky and I am afraid that this can go wrong in 1 of 1000 attempts.
if(![[NSFileManager defaultManager] fileExistsAtPath:bundlePath]) {
[[NSFileManager defaultManager] createDirectoryAtPath:bundlePath withIntermediateDirectories:YES attributes:nil error:NULL];
}
There is only this awkward method fileExistsAtPath which also looks for files and not only directories. But for me, the dangerous thing is: What if this goes wrong? What shall I do? What is best practice to guarantee that the directory is created, and only created when it does not exist?
I know file system operations are never safe. Device could loose battery power suddenly just in the moment where it began shoveling the bits from A to B. Or it can stumble upon a bad bit and hang for a second. Maybe in some seldom cases it returns YES even if there is no directory. Simply put: I don't trust file system operations.
How can I make this absolutely safe?
Ios Solutions
Solution 1 - Ios
You can actually skip the if
, even though Apple's docs say that the directory must not exist, that is only true if you are passing withIntermediateDirectories:NO
That puts it down to one call. The next step is to capture any errors:
NSError * error = nil;
[[NSFileManager defaultManager] createDirectoryAtPath:bundlePath
withIntermediateDirectories:YES
attributes:nil
error:&error];
if (error != nil) {
NSLog(@"error creating directory: %@", error);
//..
}
This will not result in an error if the directory already exists.
Solution 2 - Ios
For Swift 3.0
do {
try FileManager.default.createDirectory(atPath: folder, withIntermediateDirectories: true, attributes: nil)
} catch {
print(error)
}
Solution 3 - Ios
Swift 4.2
let fileManager = FileManager.default
let documentsURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first!
let imagesPath = documentsURL.appendingPathComponent("Images")
do
{
try FileManager.default.createDirectory(atPath: imagesPath.path, withIntermediateDirectories: true, attributes: nil)
}
catch let error as NSError
{
NSLog("Unable to create directory \(error.debugDescription)")
}
Solution 4 - Ios
Swift 5.0
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
let documentsDirectory = paths[0]
let docURL = URL(string: documentsDirectory)!
let dataPath = docURL.appendingPathComponent("MyFolder")
if !FileManager.default.fileExists(atPath: dataPath.absoluteString) {
do {
try FileManager.default.createDirectory(atPath: dataPath.absoluteString, withIntermediateDirectories: true, attributes: nil)
} catch {
print(error.localizedDescription);
}
}
Solution 5 - Ios
NSFileManager *fileManager= [NSFileManager defaultManager];
if(![fileManager fileExistsAtPath:directory isDirectory:&isDir])
if(![fileManager createDirectoryAtPath:directory withIntermediateDirectories:YES attributes:nil error:NULL])
NSLog(@"Error: Create folder failed %@", directory);
From an SO topic here.
After creating a directory, you can flush the file system then check to see if your newly created directory exists. This is probably overkill, but you can never have too much overkill.
Solution 6 - Ios
In swift 2 it looks like this:
do {
try NSFileManager.defaultManager().createDirectoryAtPath(pathURL.absoluteString, withIntermediateDirectories: true, attributes: nil)
} catch {
print(error)
}
Solution 7 - Ios
Useful if the path is like - /folder/image.png
let pathComponents = path.components(separatedBy: "/").dropLast()
var directoryPath: String = ""
for component in pathComponents {
directoryPath += component + "/"
}
do {
try FileManager.default.createDirectory(atPath: directoryPath, withIntermediateDirectories: true, attributes: nil)
} catch {
print(error)
}