Iterating through files in a folder with nested folders - Cocoa

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.

Recursive function that calls itself for every folder and looks for the file — Guidhouse, Apr 21 '11 at 20:37

score 99 · Accepted Answer · edited Apr 21 '20 at 19:31

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
    }
}

I believe the cleaner way to init NSFileManager is to use singleton method [NSFileManager defaultManager] Instead of [[[NSFileManager alloc] init] autorelease] — ProblemSlover, Jul 23 '15 at 16:44
Hi, perhaps do you know if there's a way to iterate the files using per mount point or filesystem rather than path or URL ? — Zohar81, Jan 18 '18 at 09:31

score 25 · Answer 2 · edited May 24 '19 at 15:18

25

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];
    }
  }
}

edited May 24 '19 at 15:18

Ky -

30,724
51
192
308

answered Apr 21 '11 at 20:41

Karl von Moor

8,484
4
40
52

1

Will this work correctly? The enumeration is deep so it will list the contents of all subdirectories as well. I really would like to use this but is there a way to limit the enumerator to just the current directory ? – EtienneSky May 25 '11 at 02:22
1

Just because I just saw this comment: If you dont want the sub-dirs just don't call [self openEachFileAt: file]; again. – david May 18 '12 at 15:45
Extremely late in the day but just wanted to say thanks for solving a major headache of mine. – Robert Mar 05 '13 at 16:09

score 17 · Answer 3 · edited Mar 12 '20 at 12:01

17

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)
    }
}

edited Mar 12 '20 at 12:01

Boris Y.

4,387
2
32
50

answered Jun 30 '15 at 22:47

Esqarrouth

38,543
21
161
168

9

I was searching for it and couldn't find it, then I had to solve it. I could have just asked a new question and paste my answer or just paste my answer in here. Which one is better? – Esqarrouth Jul 01 '15 at 14:09
Leave this answer here, and create one more question and paste the answer. Remember to tag swift not obj-c or cocoa. – Anoop Vaidya Jul 01 '15 at 19:30
2

@AnoopVaidya This question was asked 3 years before Swift was made public; I'm sure if this was asked by the same person for the same problem today (or, likely, even around June 30 2015), they'd prefer a Swift answer. – Ky - May 24 '19 at 15:57

score 1 · Answer 4 · answered Apr 10 '16 at 19:21

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))
    }
}

score 1 · Answer 5 · answered Jul 15 '16 at 10:36

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]);
        }
    }

score 1 · Answer 6 · answered Feb 11 '20 at 17:59

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

Iterating through files in a folder with nested folders - Cocoa

6 Answers6

Linked