iOS - Best practices for FileManager extensions - ios

Question

I created this FileManager extension. With this extension, I want to create a file hierarchy like so:
Application Support
Favorites
Feed
Images
This is the code I have in FileManager extension which I would call in app delegate as soon as the app launches. Then I would use this code to always retrieve the path's of the folders.
Is this a good way to create this hierarchy and retrieve the paths when I need them? Is this good practice?
extension FileManager {
static func createOrFindApplicationDirectory() -> URL? {
let bundleID = Bundle.main.bundleIdentifier
// Find the application support directory in the home directory.
let appSupportDir = self.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)
guard appSupportDir.count > 0 else {
return nil
}
// Append the bundle ID to the URL for the Application Support directory.
let dirPath = appSupportDir[0].appendingPathComponent(bundleID!)
// If the directory does not exist, this method creates it.
do {
try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil)
return dirPath
} catch let error {
print("Error creating Application Support directory with error: \(error)")
return nil
}
}
static func createOrFindFavoritesDirectory() -> URL? {
guard let appSupportDir = createOrFindApplicationDirectory() else {
return nil
}
let dirPath = appSupportDir.appendingPathComponent("Favorites")
// If the directory does not exist, this method creates it.
do {
try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil)
return dirPath
} catch let error {
print("Error creating Favorites directory with error: \(error)")
return nil
}
}
static func createOrFindFeedDirectory() -> URL? {
guard let appSupportDir = createOrFindFavoritesDirectory() else {
return nil
}
let dirPath = appSupportDir.appendingPathComponent("Feed")
// If the directory does not exist, this method creates it.
do {
try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil)
return dirPath
} catch let error {
print("Error creating Favorites directory with error: \(error)")
return nil
}
}
static func currentImagesDirectory() -> URL? {
guard let feedDir = createOrFindFeedDirectory() else {
return nil
}
let dirPath = feedDir.appendingPathComponent("Images")
// If the directory does not exist, this method creates it.
do {
try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil)
return dirPath
} catch let error {
print("Error creating Images directory with error: \(error)")
return nil
}
}
}

Answer 1

It looks pretty good, but you could combine a bit of the code and have better error checking:
extension FileManager {
static func createOrFindApplicationDirectory() -> URL? {
guard let bundleID = Bundle.main.bundleIdentifier else {
return nil
}
// Find the application support directory in the home directory.
let appSupportDirArray = self.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)
guard let appSupportDir = appSupportDirArray.first else {
return nil
}
// Append the bundle ID to the URL for the Application Support directory.
let dirPath = appSupportDir.appendingPathComponent(bundleID)
// If the directory does not exist, this method creates it.
do {
try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil)
return dirPath
} catch let error {
print("Error creating Application Support directory with error: \(error)")
return nil
}
}
static func createOrFindDirectory(named name: String) -> URL? {
guard let appSupportDir = createOrFindApplicationDirectory() else {
return nil
}
let dirPath = appSupportDir.appendingPathComponent(name)
// If the directory does not exist, this method creates it.
do {
try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil)
return dirPath
} catch let error {
print("Error creating \(name) directory with error: \(error)")
return nil
}
}
static func currentImagesDirectory() -> URL? {
guard let feedDir = createOrFindDirectory(named: "Feed") else {
return nil
}
let dirPath = feedDir.appendingPathComponent("Images")
// If the directory does not exist, this method creates it.
do {
try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil)
return dirPath
} catch let error {
print("Error creating Images directory with error: \(error)")
return nil
}
}
}