Iterating through files in a folder with nested folders - Cocoa - macos

Question

I need to access every file in a folder, including file that exist within nested folders. An example folder might look like this.
animals/
-k.txt
-d.jpg
cat/
-r.txt
-z.jpg
tiger/
-a.jpg
-p.pdf
dog/
-n.txt
-f.jpg
-p.pdf
Say that I wanted to run a process on every file within "animals" that isn't folder. What would be the best way to iterate through the folder "animals" and all of its subfolders to access every file?
Thanks.

Answer 1

Use NSDirectoryEnumerator to recursively enumerate files and directories under the directory you want, and ask it to tell you whether it is a file or directory. The following is based on the example listed at the documentation for -[NSFileManager enumeratorAtURL:includingPropertiesForKeys:options:errorHandler:]:
NSFileManager *fileManager = [NSFileManager defaultManager];
NSURL *directoryURL = … // URL pointing to the directory you want to browse
NSArray *keys = [NSArray arrayWithObject:NSURLIsDirectoryKey];
NSDirectoryEnumerator *enumerator = [fileManager
enumeratorAtURL:directoryURL
includingPropertiesForKeys:keys
options:0
errorHandler:^BOOL(NSURL *url, NSError *error) {
// Handle the error.
// Return YES if the enumeration should continue after the error.
return YES;
}];
for (NSURL *url in enumerator) {
NSError *error;
NSNumber *isDirectory = nil;
if (! [url getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:&error]) {
// handle error
}
else if (! [isDirectory boolValue]) {
// No error and it’s not a directory; do something with the file
}
}

Answer 2

Maybe you can use something like this:
+(void)openEachFileAt:(NSString*)path
{
NSDirectoryEnumerator* enumerator = [[NSFileManager defaultManager] enumeratorAtPath:path];
for (NSString * file in enumerator)
{
// check if it's a directory
BOOL isDirectory = NO;
NSString* fullPath = [path stringByAppendingPathComponent:file];
[[NSFileManager defaultManager] fileExistsAtPath:fullPath
isDirectory: &isDirectory];
if (!isDirectory)
{
// open your file (fullPath)…
}
else
{
[self openEachFileAt: fullPath];
}
}
}

Answer 3

Here is a swift version:
func openEachFile(inDirectory path: String) {
let subs = try! FileManager.default.subpathsOfDirectory(atPath: path)
let totalFiles = subs.count
print(totalFiles)
for sub in subs {
if sub.hasSuffix(".DS_Store") {
//a DS_Store file
}
else if sub.hasSuffix(".xcassets") {
//a xcassets file
}
else if (sub as NSString).substring(to: 4) == ".git" {
//a git file
}
else if sub.hasSuffix(".swift") {
//a swift file
}
else if sub.hasSuffix(".m") {
//a objc file
}
else if sub.hasSuffix(".h") {
//a header file
}
else {
// some other file
}
let fullPath = (path as NSString).appendingPathComponent(sub)
}
}

Answer 4

Here's a solution using -subpathsOfDirectoryAtPath:rootPath, with file URLs and modern Objective-C nullability bells & whistles.
typedef void (^FileEnumerationBlock)(NSURL *_Nonnull fileURL);
#interface NSFileManager (Extensions)
- (void)enumerateWithRootDirectoryURL:(nonnull NSURL *)rootURL
fileHandler:(FileEnumerationBlock _Nonnull)fileHandler
error:(NSError *_Nullable *_Nullable)error;
#end
#implementation NSFileManager (Extensions)
- (void)enumerateWithRootDirectoryURL:(NSURL *)rootURL
fileHandler:(FileEnumerationBlock)fileHandler
error:(NSError **)error {
NSString *rootPath = rootURL.path;
NSAssert(rootPath != nil, #"Invalid root URL %# (nil path)", rootURL);
NSArray *subs = [[NSFileManager defaultManager] subpathsOfDirectoryAtPath:rootPath
error:error];
if (!subs) {
return;
}
for (NSString *sub in subs) {
fileHandler([rootURL URLByAppendingPathComponent:sub]);
}
}
#end
… and the same in Swift:
func enumerate(rootDirectoryURL rootURL: NSURL, fileHandler:(URL:NSURL)->Void) throws {
guard let rootPath = rootURL.path else {
preconditionFailure("Invalid root URL: \(rootURL)")
}
let subs = try NSFileManager.defaultManager().subpathsOfDirectoryAtPath(rootPath)
for sub in subs {
fileHandler(URL: rootURL.URLByAppendingPathComponent(sub))
}
}

Answer 5

This code worked for me.
NSMutableString *allHash;
-(NSString*)getIterate:(NSString*)path {
allHash = [NSMutableString stringWithString:#""];
NSDirectoryEnumerator *de= [[NSFileManager defaultManager] enumeratorAtPath:path];
NSString *file;
BOOL isDirectory;
for(file in de)
{
//first check if it's a file
NSString* fullPath = [NSString stringWithFormat:#"%#/%#",path,file];
BOOL fileExistsAtPath = [[NSFileManager defaultManager] fileExistsAtPath:fullPath isDirectory:&isDirectory];
NSLog(#"Check=>%d",fileExistsAtPath);
if (!isDirectory) //its a file
{
//Do with filepath
}
else{ //it's a folder, so recurse
[self enumerateFolder:fullPath];
}
}
return allHash;
}
-(void) enumerateFolder:(NSString*)fileName
{
NSDirectoryEnumerator *de= [[NSFileManager defaultManager] enumeratorAtPath:fileName];
NSString* file;
BOOL isDirectory;
for(file in de)
{
//first check if it's a file
BOOL fileExistsAtPath = [[NSFileManager defaultManager] fileExistsAtPath:file isDirectory:&isDirectory];
if (fileExistsAtPath) {
if (!isDirectory) //its a file
{
//Do with file
}
else{ //it's a folder, so recurse
[self enumerateFolder:file];
}
}
else printf("\nenumeratefolder No file at path %s",[file UTF8String]);
}
}

Answer 6

In Swift we can try the following.
let docsDir = NSHomeDirectory().appending("/Documents")
let localFileManager = FileManager()
let dirEnum = localFileManager.enumerator(atPath: docsDir)
while let file = dirEnum?.nextObject() as? String {
if file.hasSuffix(".doc") {
print(docsDir.appending("/\(file)"))
}
}
Reference
https://developer.apple.com/documentation/foundation/filemanager/1408726-enumerator