Why data related to a URL is created before writing something? - swift4

Xcode 9.1
Swift 4
I'm trying to do some things if a property list still doesn't exist at a certain URL. The code is:
import UIKit
class ViewController: UIViewController {
let urlPers = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0].appendingPathComponent("punterosborrable.plist")
lazy var infoPunt = try? Data(contentsOf: urlPers)
override func viewDidLoad() {
super.viewDidLoad()
switch infoPunt {
case nil:
puntNUM = 1
puntALG = 1
puntGEO = 1
puntDYA = 1
default:
puntNUM = try! PropertyListDecoder().decode([Int].self, from: infoPunt!)[0]
puntALG = try! PropertyListDecoder().decode([Int].self, from: infoPunt!)[1]
puntGEO = try! PropertyListDecoder().decode([Int].self, from: infoPunt!)[2]
puntDYA = try! PropertyListDecoder().decode([Int].self, from: infoPunt!)[3]
}
Supposedly, if I don´t write anything to the Url, infoPunt should have the value nil. However, just after running the line
switch infoPunt {
the debugger shows that infoPunt.storage = (Data?) some
What does this mean? What value (or data) is infoPunt holding at this point? I thought it should be nil.
Thanks in advance

Related

How do I load a Data object into a SCNScene?

I want to load a 3d usdz blob into a view, but since I only have the data object, I'm trying to initialize the scene with that with no luck.
To that, I initialize the SCNSceneSource() and then open it using .scene().
Now what I don't understand:
If I use a URL and load the scene directly - it works.
If I use a Data object on the same URL it doesn't.
Apple docs says, the data should be of type NSData but that seems wrong.
import SceneKit
let url = URL(string: "file:///Users/thilo/Desktop/Input/UU2.usdz")!
// working
let src_ok = SCNSceneSource(url: url)
let scn_ok = src_ok?.scene(options: nil, statusHandler: {
a,b,c,d in print("OK: \(a) \(b) \(String(describing: c)) \(d) ")
})
print("Ok: \(scn_ok)")
// Not working?
let data = try! Data(contentsOf: url)
let src_bad = SCNSceneSource(data: data)
let scn_bad = src_bad?.scene(options: nil, status handler: {
a,b,c,d in print("BAD: \(a) \(b) \(String(describing: c)) \(d) ")
})
print("Failed: \(scn_bad)")
running on Playground says:
Ok: Optional(<SCNScene: 0x6000038e1200>)
BAD: 0.0 SCNSceneSourceStatus(rawValue: 4) nil 0x000000016fa948bf
BAD: 0.0 SCNSceneSourceStatus(rawValue: 4) nil 0x000000016fa942af
BAD: 0.0 SCNSceneSourceStatus(rawValue: -1) Optional(Error Domain=NSCocoaErrorDomain Code=260 "Could not load the scene" UserInfo={NSLocalizedDescription=Could not load the scene, NSLocalizedRecoverySuggestion=An error occurred while parsing the COLLADA file. Please check that it has not been corrupted.}) 0x000000016fa942af
Failed: nil
What am I missing?
SCNSceneSource doesn't support .usdz in Data context
Official documentation says that SCNSceneSource object supports only .scn, .dae and .abc file formats. But it turns out that SceneKit doesn't support URL-loading of .usdz only in the context of working with Data. Thus, when working with Data, use files in the .scn format.
import SceneKit
import Cocoa
class GameViewController : NSViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let url = URL(string: "file:///Users/swift/Desktop/ship.scn") {
let data = try! Data(contentsOf: url)
let source = SCNSceneSource(data: data)
let sceneView = self.view as! SCNView
sceneView.scene = source?.scene()
}
}
}
To load .usdz using URL, try SCNSceneSource.init?(url: URL)
class GameViewController : NSViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let url = URL(string: "file:///Users/swift/Desktop/ship.usdz") {
let source = SCNSceneSource(url: url)
let sceneView = self.view as! SCNView
sceneView.scene = source?.scene()
}
}
}
Or use SCNScene object to load .usdz model
class GameViewController : NSViewController {
override func viewDidLoad() {
super.viewDidLoad()
let url = URL(fileURLWithPath: "/Users/swift/Desktop/ship.usdz")
do {
let scene = try SCNScene(url: url)
let sceneView = self.view as! SCNView
sceneView.scene = scene
sceneView.autoenablesDefaultLighting = true
} catch {
print(error.localizedDescription)
}
}
}
Gathering from the comment "does not support usdz" my solution is:
to create a temporary file ( .usdz) seems to be required by the API...
and then manually remove the temporary file after loading.
First extend FileManager with the below code:
public extension FileManager {
func temporaryFileURL(fileName: String = UUID().uuidString,ext: String) -> URL? {
return URL(fileURLWithPath: NSTemporaryDirectory(), isDirectory: true)
.appendingPathComponent(fileName + ext)
}
}
For a limited hard-coded use case:
let fm = FileManager.default
let tempusdz = fm.temporaryFileURL(ext:".usdz")!
fm.createFile(atPath: tempusdz.path(), contents: sceneData)
let src = SCNSceneSource(url: tempusdz)
if let scene = src?.scene(options: nil) {
....
}
try? fm.removeItem(at: tempusdz)
of course this is a hack, because it will only work if the data is in usdz format.
Since usdz is a ZIP archive, maybe testing for a zip and then just doing the below is a better option:
let sceneData:Data? = data
var sceneSrc: SCNSceneSource? = nil
var tempURL:URL? = nil
if let dataStart = sceneData?.subdata(in: 0..<4),
let dataMagic = String(data: dataStart, encoding: String.Encoding.utf8) as String?,
dataMagic == "PK\u{3}\u{4}" {
let fm = FileManager.default
tempURL = fm.temporaryFileURL(ext: ".usdz")
if let tempURL {
fm.createFile(atPath: tempURL.path(), contents: sceneData)
sceneSrc = SCNSceneSource(url: tempURL)
}
} else {
sceneSrc = SCNSceneSource(data: sceneData!)
}
let scene = sceneSrc?.scene()
if let tempURL {
try? FileManager.default.removeItem(at: tempURL)
}
Does anyone knows a better solution?
Is there an easy way to check the type of the Data ?
potential solution could be to verify the format of the data object and ensure that it is a valid COLLADA file.
import Foundation
let url = URL(string: "file:///Users/thilo/Desktop/Input/UU2.usdz")!
let data = try! Data(contentsOf: url)
print("Data size: \(data.count)")
print("Data format: \(data.description)")
you usually get these types of errors when the data wasn't properly formatted

RealityKit – macOS Photogrammetry app's Error

For the past few days I've tried creating a photogrammetry command line app in Xcode. But I keep getting an error when I try to run the code.
The error I get is the following:
[Photogrammetry] queueNextProcessingBatchIfNeeded(): Already running a job... not starting new one.
I've searched on Google but I can't find anyone who has experienced the same issue.
The code I'm using is the following:
import Foundation
import RealityKit
let inputFolderUrl = URL(fileURLWithPath: "/Users/username/Desktop/AirForce", isDirectory: true)
let session = try! PhotogrammetrySession(input: inputFolderUrl, configuration: PhotogrammetrySession.Configuration())
try! session.process(requests: [.modelFile(url: URL(fileURLWithPath: "/Users/username/Desktop/MyModel.usdz"), detail: .preview)])
My system:
MacBook Air (M1, 2020)
macOS Monterey 12.0.1 (21A559)
Xcode Version 13.2.1 (13C100)
Use my code. It works. If you need more details on photogrammetry, read my Medium post.
import Cocoa
import RealityKit
struct Photogrammetry {
typealias Config = PhotogrammetrySession.Configuration
typealias Request = PhotogrammetrySession.Request
var inputFolder = "/Users/swift/Desktop/WildBoar"
var outputFile = "/Users/swift/Desktop/wildBoar.usdz"
var detail: Request.Detail = .medium
fileprivate func running() {
var config = PhotogrammetrySession.Configuration()
config.featureSensitivity = .normal
config.isObjectMaskingEnabled = true
config.sampleOrdering = .unordered
let inputFolderURL = URL(fileURLWithPath: inputFolder,
isDirectory: true)
var optionalSession: PhotogrammetrySession? = nil
do {
optionalSession = try PhotogrammetrySession(
input: inputFolderURL,
configuration: config)
} catch {
print("ERROR")
Foundation.exit(1)
}
guard let session = optionalSession
else { Foundation.exit(1) }
withExtendedLifetime(session) {
do {
let request = PhotogrammetrySession.Request
.modelFile(url: URL(fileURLWithPath: outputFile),
detail: detail)
try session.process(requests: [request])
RunLoop.main.run()
} catch {
print("ERROR")
Foundation.exit(1)
}
}
}
}
Hello I had the same problem I solved it by adding a single line.
RunLoop.main.run()
import Foundation
import RealityKit
let inputFolderURL = URL(fileURLWithPath: "/Users/saibalaji/Desktop/ObjectCapture/ObjectCapture/Images/camera",isDirectory: true)
let outputURL = URL(fileURLWithPath: "/Users/saibalaji/Desktop/ObjectCapture/ObjectCapture/Camera.usdz")
let session = try! PhotogrammetrySession(input: inputFolderURL, configuration: PhotogrammetrySession.Configuration())
let request = PhotogrammetrySession.Request.modelFile(url: outputURL, detail: .medium)
try! session.process(requests: [request])
RunLoop.main.run()

Unable to make network call

I'm trying to make a network call to forecast.io for a weather forecast. My code looks like this:
class ViewController: UIViewController {
private let apiKey = "" // 32 letters and numbers
override func viewDidLoad() {
super.viewDidLoad()
let baseURL = NSURL(string: "https://developer.forecast.io/forecast/\(apiKey)/")
let forecastURL = NSURL(string: "37.8267,-122.423", relativeToURL: baseURL)
let weatherData = NSData(contentsOfURL: forecastURL!, options: nil, error: nil)
println(weatherData)
}
}
The println() just returns nil. When I log in to forecast.io I see I haven't yet made a call. What's wrong with my code?
The problem lies in url:
"https://developer.forecast.io/forecast/
should be
"https://api.forecast.io/forecast/

Swift NSDirectoryEnumerator Generator [duplicate]

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.

Iterate through files in a folder and its subfolders using Swift's FileManager

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.