Cannot sync simple text file with iCloud (bad file descriptor)

Question

I'm having trouble synching a simple textfile, I get this error when trying to open it:

{NSFilePath=/private/var/mobile/Library/Mobile Documents/4C224W52W5~com~piso13~opusDomini/currentLogPath, NSUnderlyingError=0xde9b460 "The operation couldn‚Äôt be completed. Bad file descriptor"}

This is how I create it

-(BOOL)createLogFolderFile{        

    NSString *uuid = nil;

    CFUUIDRef uuidRef = CFUUIDCreate(nil);

    uuid = (NSString*)CFUUIDCreateString(nil, uuidRef);

    CFRelease(uuidRef);    



    NSError *error = nil;

    [uuid writeToFile:[self filePath] atomically:NO encoding:NSUTF8StringEncoding error:&error];

    if (error) {

        NSLog(@"Error trying to create log file %@", error);        

        return FALSE;

    }

    else{

        return TRUE;

    }

}

-(NSString*)filePath{

    NSFileManager *fileManager = [NSFileManager defaultManager];

    NSString *iCloudPath = [[fileManager URLForUbiquityContainerIdentifier:nil] path];

    return [iCloudPath stringByAppendingPathComponent:LOG_FOLDER_FILE_NAME];

}

This is how I read it:

-(NSString*)readLogFolderFromFile{

    NSError *error = nil;

    NSString *logFolder = [NSString stringWithContentsOfFile:[self filePath] encoding:NSUTF8StringEncoding error:&error];

    if (error) {

        NSLog(@"Error when trying to read log folder from file: %@" ,error);

        return nil;

    }

    else{

        return logFolder;

    }

}

I'm using NSMetadataQuery to search for the file, The notification query finish gathering info results positive.

Help?

In your `filePath` method, what value are you getting assigned to the `iCloudPath` variable? — Peter Hosey, Jan 03 '12 at 16:42
Also, are you getting that error when reading or when writing? — Peter Hosey, Jan 03 '12 at 16:43
iCloudPath gets: /private/var/mobile/Library/Mobile Documents/4C224W52W5~com~piso13~opusDomini — the Reverend, Jan 03 '12 at 17:06

score 5 · Accepted Answer · answered Jan 03 '12 at 18:39

The file was not downloaded. It seems NSMetadataQuery notifies about the existence of the file in the cloud. To actually get the file, extra code is needed:

Inside queryDidFinishGathering notification:

 NSMetadataItem *item = [query resultAtIndex:0];
        self.metadataItem = item;
        BOOL isDownloaded = [[item valueForAttribute:NSMetadataUbiquitousItemIsDownloadedKey]boolValue];

  if (!isDownloaded) {
        NSError *error = nil;
        [[NSFileManager defaultManager] startDownloadingUbiquitousItemAtURL: [item valueForAttribute:NSMetadataItemURLKey] error:&error];
        NSLog(@"Start downloading file");
        if (error) {
            NSLog(@"Error trying to download file: %@", error);
        }
        else{
            [self lookForLogFolderFile];
            return;
        }

    }

The lookForLogFolderFile simply starts the query again. After several calls my item gets downloaded. You can also use a timer to between each call to start a NSMetadataQuery. In my case, is just a text file with one line.

Cannot sync simple text file with iCloud (bad file descriptor)

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