I’m creating a Multiplatform SwiftUI app.
After some initial struggles, I was able to create a directory of files and add them to my app’s bundle. At launch time, I try to use the Bundle function Bundle.main.paths(forResourcesOfType:) to find those files and open them.
The Mac version of the app finds the files just fine. When I run the same code on the iOS version, it returns an empty array of file paths.
I can navigate to the app bundle for the simulator version of the app in the finder, open it with “show package contents”, and see my folder in the bundle plain as day, with the files I’ve written to it. However, Bundle.main.paths(forResourcesOfType:) returns an empty list.
I initially tried getting the bundle resources path appending my folder name to that, and using the file manager to fetch the list of files, but that failed, so I switched to using the Bundle method.
Both approaches work on macOS, and both fail on iOS.
Is there some sandboxing issue I’m not aware of?
Here is my code:
static var scopeTemplates: [ScopeTemplate] = {
let fileManager = FileManager.default
let folderName = "Kaleidoscope_Templates"
do {
if let bundlePath = Bundle.main.resourcePath {
print("bundlePath = \(bundlePath)")
} else {
print("Can't resolve bundle path")
}
// old path-based code.
//let kaleidoscopeTemplateFileNames = Bundle.main.paths(forResourcesOfType: "json", inDirectory: folderName)
//let kaleidoscopeTemplateURLs = kaleidoscopeTemplateFileNames.map { URL(filePath: $0) }
guard let kaleidoscopeTemplateURLs = Bundle.main.urls(forResourcesWithExtension: "json", subdirectory: folderName) else {
fatalError("Can't find folder \(folderName)")
}
let decoder = JSONDecoder()
var scopeTemplates = [ScopeTemplate]()
for aFileURL in kaleidoscopeTemplateURLs {
print("filename = \(aFileURL.path)")
let data = try Data(contentsOf: aFileURL)
let aScopeTemplate = try decoder.decode(ScopeTemplate.self, from: data)
scopeTemplates.append(aScopeTemplate)
}
return scopeTemplates.sorted() { lhv, rhv in
return lhv.index < rhv.index
}
} catch {
fatalError("Error \(error) reading template files")
}
}()
(This version of the code doesn’t crash, and doesn’t log any errors, but it returns an empty array. The FileManager version threw an exception on iOS when I tried to fetch the files in my directory, but that version also worked on macOS.)
Also note that the bundle structure looks identical in iOS and MacOS. I use the finder “Go to Folder” menu command to open the directory in the bundle in the sim and it looks exactly as expected.
I just created a minimum repeatable project and published it on Github:
That code looks like this:
static var scopeTemplates: [ScopeTemplate] = {
let fileManager = FileManager.default
let folderName = "Kaleidoscope_Templates"
do {
if let bundlePath = Bundle.main.resourcePath {
print("bundlePath = \(bundlePath)")
} else {
print("Can't resolve bundle path")
}
guard let kaleidoscopeTemplateURLs = Bundle.main.urls(forResourcesWithExtension: "json", subdirectory: folderName) else {
fatalError("Can't find folder \(folderName)")
}
print("Directory \(folderName) in bundle resources contains \(kaleidoscopeTemplateURLs.count) files.")
let decoder = JSONDecoder()
var scopeTemplates = [ScopeTemplate]()
for aFileURL in kaleidoscopeTemplateURLs {
print("filename = \(aFileURL.path)")
let data = try Data(contentsOf: aFileURL)
let aScopeTemplate = try decoder.decode(ScopeTemplate.self, from: data)
scopeTemplates.append(aScopeTemplate)
}
return scopeTemplates.sorted() { lhv, rhv in
return lhv.index < rhv.index
}
} catch {
fatalError("Error \(error) reading template files")
}
}()
(The project on Github has the Xcode project, the folder-full of files, etc. It’ is set up as a SwiftUI Multiplatform project just like the real app I’m struggling with.)
When run in the iOS simulator it logs the bundle path as expected:
bundlePath = /Users/duncan/Library/Developer/CoreSimulator/Devices/EABDE8A8-0CAC-4D5F-81EF-FB03DC809EE5/data/Containers/Bundle/Application/8EA76044-8F14-4783-A45B-423A35F1EB4F/BundleFiles.app
And then logs
Directory Kaleidoscope_Templates in bundle resources contains 0 files.
The same code run on my Mac loads and decodes the 4 files from the bundle as it should.
When run on a Mac, the bundle path ends with Contents/Resources, but on iOS, it is the top-level app bundle directory. (I believe that is expected behavior.)
