I'm currently learning Swift 2 on XCode 7 and trying to figure out how to test if a property list is available to read from.
I have a convenience initializer that works but I want to implement a test to see if the propertyList exists, otherwise just create an empty array.
Here's my code far:
Property List creation and write
let propertyList: NSArray = photoGrid.photos.map { $0.propertyListRepresentation() }
let path = NSSearchPathForDirectoriesInDomains(
.DocumentDirectory,
.UserDomainMask,
true)[0] as NSString
let file = path.stringByAppendingPathComponent("data.plist")
propertyList.writeToFile(file, atomically: true)
Convenience Init
convenience init(propertyList: NSArray) {
self.init()
// test if property list exists {
self.photos = propertyList.map { (param: AnyObject) -> Photo in
let pl = param as! NSDictionary
let photo = Photo(propertyList: pl)
return photo!
}
// } else {
// print("Property List does not exist... Created empty object array)
}
First of all use the URL related API to get the file URL
let documentDirectoryURL = try! NSFileManager.defaultManager().URLForDirectory(.DocumentDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false)
let fileURL = documentDirectoryURL.URLByAppendingPathComponent("data.plist")
Second of all, there is a class NSPropertyListSerialization which is preferable to the implicit property list serialization of NSArray.
Third of all, in Swift use native collection types rather than the type-unspecified Foundation classes.
This is an init method which creates the file URL, checks file exists and assigns the mapped Photo instances or an empty Photo array to the instance variable.
init() {
let documentDirectoryURL = try! NSFileManager.defaultManager().URLForDirectory(.DocumentDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false)
let fileURL = documentDirectoryURL.URLByAppendingPathComponent("data.plist")
if let data = NSData(contentsOfURL:fileURL), propertyList = try! NSPropertyListSerialization.propertyListWithData(data, options: [], format: nil) as? [[String:AnyObject]] {
self.photos = propertyList.map { Photo(propertyList: $0)! }
} else {
self.photos = [Photo]()
}
}
The two try! expressions are safe because the document directory exists and the property list file has a predictable format.
Related
I want to check the pdf file with a perticular user name is available in my document directory or not. By using following code i am able to do this. But when there is no data is avalable in the document directory i want to show user a message. But i am unable to show user any message. How do do this? can anyone help me?
private func checkPatientPdfIsPresentOrNot(selectedPatient: String, completion: (_ present: Bool) -> Void){
if let documentsPathString = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first {
let filemanager = FileManager.default
if let files = filemanager.enumerator(atPath: documentsPathString){
while let file = files.nextObject() {
let nameWithDate = (file as! String).components(separatedBy: ".")
let fileName = nameWithDate[0]
let namewithoutDate = fileName.components(separatedBy: "_")
let name = namewithoutDate[0]
if name == selectedPatient.capitalized{
completion(true)
}
else{
completion(false)
}
}
}
else{
completion(false)
}
}
}
First of all there are – in terms of Swift – a lot of outdated APIs in your code.
Second of all as the entire code is synchronous the completion handler is pointless.
The major issue is that the completion handler is called multiple times. You should call it once passing true if the partial file name matches selectedPatient or passing false after the loop.
This is a suggestion with more contemporary code and a boolean return value.
Show the message to the user if method returns false
private func checkPatientPdfIsPresentOrNot(selectedPatient: String) -> Bool {
let fileManager = FileManager.default
do {
let documentsURL = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let fileURLs = try fileManager.contentsOfDirectory(at: documentsURL, includingPropertiesForKeys: [.nameKey], options: .skipsHiddenFiles)
return fileURLs.first(where: { url -> Bool in
let fileName = url.deletingPathExtension().lastPathComponent
return fileName.components(separatedBy: "_").first == selectedPatient.capitalized
}) != nil
} catch { print(error); return false }
}
I need to get the contents from multiple plist files and bring them into a single dictionary which is then displayed in a tableView
Using this code I can manually get each path and the contents of the file but I need to be able to do this for all plist files in the directory not just these predefined ones.
func getFiles() {
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
let path = documentDirectory.appending("/MainFolder/File1.plist")
let path1 = documentDirectory.appending("/MainFolder/File2.plist")
let path2 = documentDirectory.appending("/MainFolder/File3.plist")
tableViewData = [NSDictionary(contentsOfFile: path) as! [String : String], NSDictionary(contentsOfFile: path1) as! [String : String], NSDictionary(contentsOfFile: path2) as! [String : String]]
print(tableViewData)
}
I the display tableViewData in my tableView which gives me each files contents on its own row.
I am guessing I probably need an array of file urls filtered by .plist and then some way to get the contents of each file into a [String : String] dictionary.
I am new to swift, any help or a better way to do this would be great
First of all don't use outdated and objective-c-ish NSSearchPathForDirectoriesInDomains in Swift. Use the modernFileManager API.
Second of all don't use objective-c-ish NSDictionary(contentsOf to read property list data. Use PropertyListSerialization.
The function throws that means it hands over all possible errors to the caller. It filters the URLs in the directory by the plist extension and uses the map function to get the dictionary for each URL.
func getFiles() throws {
let documentDirectory = try FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let subFolderURL = documentDirectory.appendingPathComponent("MainFolder")
let allFiles = try FileManager.default.contentsOfDirectory(at: subFolderURL, includingPropertiesForKeys: nil)
let properListFiles = allFiles.filter{$0.pathExtension == "plist"}
tableViewData = try properListFiles.compactMap { url -> [String:String]? in
let data = try Data(contentsOf: url)
return try PropertyListSerialization.propertyList(from: data, format: nil) as? [String:String]
}
print(tableViewData)
}
Be aware that in sandboxed apps the Documents folder is located in the application container.
You can read all the plists and iterate over them adding their contents either to 1 array, or to an already kept dictionary.
do {
let directoryContents = try FileManager.default.contentsOfDirectory(at: documentDirectory, includingPropertiesForKeys: nil, options: [])
let allPlistFiles = directoryContents.filter{ $0.pathExtension == "plist" }
var aPlistArray = []
for aPlist in allPlistFiles {
aPlistArray.append(NSDictionary(contentsOfFile: path) as! [String : String])
}
} catch {
print(error)
}
I'm trying to make a String extension that searches for a file in my app's directory and either returns that file or returns false if it does not exist. Here's what I have:
extension String {
func doesFileWithNameExist() -> Bool {
let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
let url = NSURL(fileURLWithPath: path)
let filePath = url.appendingPathComponent(self+".png")?.path
let fileManager = FileManager.default
if fileManager.fileExists(atPath: filePath!) {
return true
} else {
return false
}
}
}
Right now my function just returns a Bool, but I'm wondering if there's a way to just return the file if it exists, otherwise return false. Is there a way to return different value types from a function?
It's highly recommended to use the URL related API. This returns an optional UIImage:
extension String {
func doesFileWithNameExist() -> UIImage? { // maybe better pngImageInDocumentsFolder()
let fileManager = FileManager.default
do {
let url = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let fullURL = url.appendingPathComponent(self).appendingPathExtension("png")
_ = try fullURL.checkResourceIsReachable()
let data = try Data(contentsOf: fullURL)
return UIImage(data: data)
} catch {
return nil
}
}
}
or using Leo's great reduction (slightly still reduced):
var image: UIImage? {
guard let url = try? FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false).appendingPathComponent(self).appendingPathExtension("png"),
let data = try? Data(contentsOf: url) else { return nil }
return UIImage(data: data)
}
You can return an optional value here, which in Swift is "a thing or nil" – very close to "that file or false." For example, here's a quick tweak to your extension function that returns the path if a file exists there, or nil otherwise:
extension String {
func doesFileWithNameExist() -> String? {
let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
let url = NSURL(fileURLWithPath: path)
let filePath = url.appendingPathComponent(self+".png")?.path
let fileManager = FileManager.default
if fileManager.fileExists(atPath: filePath!) {
return filePath
} else {
return nil
}
}
}
A quick editorial comment, though: this kind of behavior doesn't seem especially well-suited to a String extension. I'd consider writing an extension on FileManager instead, passing in a string for the file's name. Given the hardcoding of the "png" extension, maybe something with the following signature?
extension FileManager {
func pathToExistingPNGFile(named name: String) -> String? {
// …
}
}
I'm quite new to programming a Swift and I'm trying to iterate through the files in a folder.
I took a look at the answer here and tried to translate it to Swift syntax, but didn't succeed.
let fileManager = NSFileManager.defaultManager()
let enumerator:NSDirectoryEnumerator = fileManager.enumeratorAtPath(folderPath)
for element in enumerator {
//do something
}
the error I get is:
Type 'NSDirectoryEnumerator' does not conform to protocol 'SequenceType'
My aim is to look at all the subfolders and files contained into the main folder and find all the files with a certain extension to then do something with them.
Use the nextObject() method of enumerator:
while let element = enumerator?.nextObject() as? String {
if element.hasSuffix("ext") { // checks the extension
}
}
Nowadays (early 2017) it's highly recommended to use the – more versatile – URL related API
let fileManager = FileManager.default
do {
let resourceKeys : [URLResourceKey] = [.creationDateKey, .isDirectoryKey]
let documentsURL = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let enumerator = FileManager.default.enumerator(at: documentsURL,
includingPropertiesForKeys: resourceKeys,
options: [.skipsHiddenFiles], errorHandler: { (url, error) -> Bool in
print("directoryEnumerator error at \(url): ", error)
return true
})!
for case let fileURL as URL in enumerator {
let resourceValues = try fileURL.resourceValues(forKeys: Set(resourceKeys))
print(fileURL.path, resourceValues.creationDate!, resourceValues.isDirectory!)
}
} catch {
print(error)
}
I couldn't get pNre's solution to work at all; the while loop just never received anything. However, I did come across this solution which works for me (in Xcode 6 beta 6, so perhaps things have changed since pNre posted the above answer?):
for url in enumerator!.allObjects {
print("\((url as! NSURL).path!)")
}
my two cents from previously anwers.. more swifty and with optionals:
let enumerator = FileManager.default.enumerator(atPath: folderPath)
while let element = enumerator?.nextObject() as? String {
print(element)
if let fType = enumerator?.fileAttributes?[FileAttributeKey.type] as? FileAttributeType{
switch fType{
case .typeRegular:
print("a file")
case .typeDirectory:
print("a dir")
}
}
}
returns all files in a directory + in subdirectories
import Foundation
let path = "<some path>"
let enumerator = FileManager.default.enumerator(atPath: path)
while let filename = enumerator?.nextObject() as? String {
print(filename)
}
Swift3 + absolute urls
extension FileManager {
func listFiles(path: String) -> [URL] {
let baseurl: URL = URL(fileURLWithPath: path)
var urls = [URL]()
enumerator(atPath: path)?.forEach({ (e) in
guard let s = e as? String else { return }
let relativeURL = URL(fileURLWithPath: s, relativeTo: baseurl)
let url = relativeURL.absoluteURL
urls.append(url)
})
return urls
}
}
Based on code from #user3441734
Swift 3
let fd = FileManager.default
fd.enumerator(atPath: "/Library/FileSystems")?.forEach({ (e) in
if let e = e as? String, let url = URL(string: e) {
print(url.pathExtension)
}
})
In case that you are getting the
'NSDirectoryEnumerator?' does not have a member named 'nextObject' error
the while loop should be:
while let element = enumerator?.nextObject() as? String {
// do things with element
}
It has something to do with optional chaining
SWIFT 3.0
Returns all files with extension in the Directory passed & its subdirectories
func extractAllFile(atPath path: String, withExtension fileExtension:String) -> [String] {
let pathURL = NSURL(fileURLWithPath: path, isDirectory: true)
var allFiles: [String] = []
let fileManager = FileManager.default
let pathString = path.replacingOccurrences(of: "file:", with: "")
if let enumerator = fileManager.enumerator(atPath: pathString) {
for file in enumerator {
if #available(iOS 9.0, *) {
if let path = NSURL(fileURLWithPath: file as! String, relativeTo: pathURL as URL).path, path.hasSuffix(".\(fileExtension)"){
let fileNameArray = (path as NSString).lastPathComponent.components(separatedBy: ".")
allFiles.append(fileNameArray.first!)
}
} else {
// Fallback on earlier versions
print("Not available, #available iOS 9.0 & above")
}
}
}
return allFiles
}
Updating for Swift 3:
let fileManager = FileManager() // let fileManager = NSFileManager.defaultManager()
let en=fileManager.enumerator(atPath: the_path) // let enumerator:NSDirectoryEnumerator = fileManager.enumeratorAtPath(folderPath)
while let element = en?.nextObject() as? String {
if element.hasSuffix("ext") {
// do something with the_path/*.ext ....
}
}
Adding to vadian's response -- the Apple docs mention that Path-based URLs are simpler in some ways, however file reference URLs have the advantage that the reference remains valid if the file is moved or renamed while your app is running.
From the documentation for "Accessing Files and Directories":
"Path-based URLs are easier to manipulate, easier to debug, and are generally preferred by classes such as NSFileManager. An advantage of file reference URLs is that they are less fragile than path-based URLs while your app is running. If the user moves a file in the Finder, any path-based URLs that refer to the file immediately become invalid and must be updated to the new path. However, as long as the file moved to another location on the same disk, its unique ID does not change and any file reference URLs remain valid."
https://developer.apple.com/library/content/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/AccessingFilesandDirectories/AccessingFilesandDirectories.html
If you want to categorically check whether an element is a file or a subdirectory:
let enumerator = FileManager.default.enumerator(atPath: contentsPath);
while let element = enumerator?.nextObject() as? String {
if(enumerator?.fileAttributes?[FileAttributeKey.type] as! FileAttributeType == FileAttributeType.typeRegular){
//this is a file
}
else if(enumerator?.fileAttributes?[FileAttributeKey.type] as! FileAttributeType == FileAttributeType.typeDirectory){
//this is a sub-directory
}
}
Recently struggled with this when handling an array of urls, whether they be a directory or not (eg. drag and drop). Ended up with this extension in swift 4, may be of use
extension Sequence where Iterator.Element == URL {
var handleDir: [URL] {
var files: [URL] = []
self.forEach { u in
guard u.hasDirectoryPath else { return files.append(u.resolvingSymlinksInPath()) }
guard let dir = FileManager.default.enumerator(at: u.resolvingSymlinksInPath(), includingPropertiesForKeys: nil) else { return }
for case let url as URL in dir {
files.append(url.resolvingSymlinksInPath())
}
}
return files
}
}
Avoid reference URLs, while they do have some advantages as stated above, they eat system resources and if you’re enumerating a large filesystem (not that large actually) your app will hit a system wall quickly and get shutdown by macOS.
I'm quite new to programming a Swift and I'm trying to iterate through the files in a folder.
I took a look at the answer here and tried to translate it to Swift syntax, but didn't succeed.
let fileManager = NSFileManager.defaultManager()
let enumerator:NSDirectoryEnumerator = fileManager.enumeratorAtPath(folderPath)
for element in enumerator {
//do something
}
the error I get is:
Type 'NSDirectoryEnumerator' does not conform to protocol 'SequenceType'
My aim is to look at all the subfolders and files contained into the main folder and find all the files with a certain extension to then do something with them.
Use the nextObject() method of enumerator:
while let element = enumerator?.nextObject() as? String {
if element.hasSuffix("ext") { // checks the extension
}
}
Nowadays (early 2017) it's highly recommended to use the – more versatile – URL related API
let fileManager = FileManager.default
do {
let resourceKeys : [URLResourceKey] = [.creationDateKey, .isDirectoryKey]
let documentsURL = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let enumerator = FileManager.default.enumerator(at: documentsURL,
includingPropertiesForKeys: resourceKeys,
options: [.skipsHiddenFiles], errorHandler: { (url, error) -> Bool in
print("directoryEnumerator error at \(url): ", error)
return true
})!
for case let fileURL as URL in enumerator {
let resourceValues = try fileURL.resourceValues(forKeys: Set(resourceKeys))
print(fileURL.path, resourceValues.creationDate!, resourceValues.isDirectory!)
}
} catch {
print(error)
}
I couldn't get pNre's solution to work at all; the while loop just never received anything. However, I did come across this solution which works for me (in Xcode 6 beta 6, so perhaps things have changed since pNre posted the above answer?):
for url in enumerator!.allObjects {
print("\((url as! NSURL).path!)")
}
my two cents from previously anwers.. more swifty and with optionals:
let enumerator = FileManager.default.enumerator(atPath: folderPath)
while let element = enumerator?.nextObject() as? String {
print(element)
if let fType = enumerator?.fileAttributes?[FileAttributeKey.type] as? FileAttributeType{
switch fType{
case .typeRegular:
print("a file")
case .typeDirectory:
print("a dir")
}
}
}
returns all files in a directory + in subdirectories
import Foundation
let path = "<some path>"
let enumerator = FileManager.default.enumerator(atPath: path)
while let filename = enumerator?.nextObject() as? String {
print(filename)
}
Swift3 + absolute urls
extension FileManager {
func listFiles(path: String) -> [URL] {
let baseurl: URL = URL(fileURLWithPath: path)
var urls = [URL]()
enumerator(atPath: path)?.forEach({ (e) in
guard let s = e as? String else { return }
let relativeURL = URL(fileURLWithPath: s, relativeTo: baseurl)
let url = relativeURL.absoluteURL
urls.append(url)
})
return urls
}
}
Based on code from #user3441734
Swift 3
let fd = FileManager.default
fd.enumerator(atPath: "/Library/FileSystems")?.forEach({ (e) in
if let e = e as? String, let url = URL(string: e) {
print(url.pathExtension)
}
})
In case that you are getting the
'NSDirectoryEnumerator?' does not have a member named 'nextObject' error
the while loop should be:
while let element = enumerator?.nextObject() as? String {
// do things with element
}
It has something to do with optional chaining
SWIFT 3.0
Returns all files with extension in the Directory passed & its subdirectories
func extractAllFile(atPath path: String, withExtension fileExtension:String) -> [String] {
let pathURL = NSURL(fileURLWithPath: path, isDirectory: true)
var allFiles: [String] = []
let fileManager = FileManager.default
let pathString = path.replacingOccurrences(of: "file:", with: "")
if let enumerator = fileManager.enumerator(atPath: pathString) {
for file in enumerator {
if #available(iOS 9.0, *) {
if let path = NSURL(fileURLWithPath: file as! String, relativeTo: pathURL as URL).path, path.hasSuffix(".\(fileExtension)"){
let fileNameArray = (path as NSString).lastPathComponent.components(separatedBy: ".")
allFiles.append(fileNameArray.first!)
}
} else {
// Fallback on earlier versions
print("Not available, #available iOS 9.0 & above")
}
}
}
return allFiles
}
Updating for Swift 3:
let fileManager = FileManager() // let fileManager = NSFileManager.defaultManager()
let en=fileManager.enumerator(atPath: the_path) // let enumerator:NSDirectoryEnumerator = fileManager.enumeratorAtPath(folderPath)
while let element = en?.nextObject() as? String {
if element.hasSuffix("ext") {
// do something with the_path/*.ext ....
}
}
Adding to vadian's response -- the Apple docs mention that Path-based URLs are simpler in some ways, however file reference URLs have the advantage that the reference remains valid if the file is moved or renamed while your app is running.
From the documentation for "Accessing Files and Directories":
"Path-based URLs are easier to manipulate, easier to debug, and are generally preferred by classes such as NSFileManager. An advantage of file reference URLs is that they are less fragile than path-based URLs while your app is running. If the user moves a file in the Finder, any path-based URLs that refer to the file immediately become invalid and must be updated to the new path. However, as long as the file moved to another location on the same disk, its unique ID does not change and any file reference URLs remain valid."
https://developer.apple.com/library/content/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/AccessingFilesandDirectories/AccessingFilesandDirectories.html
If you want to categorically check whether an element is a file or a subdirectory:
let enumerator = FileManager.default.enumerator(atPath: contentsPath);
while let element = enumerator?.nextObject() as? String {
if(enumerator?.fileAttributes?[FileAttributeKey.type] as! FileAttributeType == FileAttributeType.typeRegular){
//this is a file
}
else if(enumerator?.fileAttributes?[FileAttributeKey.type] as! FileAttributeType == FileAttributeType.typeDirectory){
//this is a sub-directory
}
}
Recently struggled with this when handling an array of urls, whether they be a directory or not (eg. drag and drop). Ended up with this extension in swift 4, may be of use
extension Sequence where Iterator.Element == URL {
var handleDir: [URL] {
var files: [URL] = []
self.forEach { u in
guard u.hasDirectoryPath else { return files.append(u.resolvingSymlinksInPath()) }
guard let dir = FileManager.default.enumerator(at: u.resolvingSymlinksInPath(), includingPropertiesForKeys: nil) else { return }
for case let url as URL in dir {
files.append(url.resolvingSymlinksInPath())
}
}
return files
}
}
Avoid reference URLs, while they do have some advantages as stated above, they eat system resources and if you’re enumerating a large filesystem (not that large actually) your app will hit a system wall quickly and get shutdown by macOS.