Copy file from Files app fails even with startAccessingSecurityScopedResource

Question

My app supports opening a document in place. However, under a certain condition, I would like to copy it to my local sandbox. I followed Copy file from iOS 11 Files app to sandbox and used [NSURL startAccessingSecurityScopedResource].

I verified that the file exists, but the copy operation fails, reporting that the file doesn't exist.

Following is my code in the app delegate.

    if (openedInPlace) {
        NSString *urlString = [url absoluteString];
        if ([urlString containsString:@"/Downloads/"]) {

            NSFileCoordinator *fileCoordinator = [[NSFileCoordinator alloc] initWithFilePresenter:nil];
            NSError *coordinatorError = nil;
            __block BOOL leaveInPlace = YES;
            __block NSURL *fileURL;
            [fileCoordinator coordinateReadingItemAtURL:url options:NSFileCoordinatorReadingWithoutChanges error:&coordinatorError byAccessor:^(NSURL *newURL)
            {
                // Copy to local inbox
                NSFileManager *fm = [NSFileManager defaultManager];
                NSURL *docs = [fm URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:nil];
                NSURL *inbox = [docs URLByAppendingPathComponent:@"Inbox" isDirectory:YES];
                //NSURL *fileURL = [inbox URLByAppendingPathComponent:[url lastPathComponent]];
                fileURL = [inbox URLByAppendingPathComponent:@"test_doc.ptw"];
                
                BOOL result;
                NSLog(@"Copy from %@ to %@", newURL, fileURL);
                result = [newURL startAccessingSecurityScopedResource];
                NSLog(@"startAccessingSecurityScopedResource %@", result ? @"succeeded" : @"did not succeed.");
                result = [fm fileExistsAtPath:newURL.path];
                NSLog(@"File %@ %@", newURL.path, result ? @"exists" : @"doesn't exist");

                NSError *copyError = nil;
                [fm copyItemAtURL:newURL toURL:fileURL error:&copyError];
                if (!copyError)
                {
                    // OK
                    leaveInPlace = NO;
                }
                else
                {
                    NSLog(@"Files app error: %@", copyError);
                    leaveInPlace = YES;
                    result = [fm fileExistsAtPath:newURL.path];
                    NSLog(@"File %@ %@", newURL.path, result ? @"exists" : @"doesn't exist");
                }
                
                [newURL stopAccessingSecurityScopedResource];
            }];
            openedInPlace = leaveInPlace;
            if (! openedInPlace)
                url = fileURL;
        }
    }

And here is the log:

Copy from file:///private/var/mobile/Containers/Shared/AppGroup/E6E86AC8-4E2F-45B2-9842-FB6AAE29D31E/File%20Provider%20Storage/Downloads/Bloc%202.ptw to file:///var/mobile/Containers/Data/Application/912852F7-9C16-4D9C-B9C9-6A0126C92C40/Documents/Inbox/test_doc.ptw
startAccessingSecurityScopedResource succeeded
File /private/var/mobile/Containers/Shared/AppGroup/E6E86AC8-4E2F-45B2-9842-FB6AAE29D31E/File Provider Storage/Downloads/Bloc 2.ptw exists
Files app error: Error Domain=NSCocoaErrorDomain Code=4 "The file “Bloc 2.ptw” doesn’t exist." UserInfo={NSSourceFilePathErrorKey=/private/var/mobile/Containers/Shared/AppGroup/E6E86AC8-4E2F-45B2-9842-FB6AAE29D31E/File Provider Storage/Downloads/Bloc 2.ptw, NSUserStringVariant=(
    Copy
), NSDestinationFilePath=/var/mobile/Containers/Data/Application/912852F7-9C16-4D9C-B9C9-6A0126C92C40/Documents/Inbox/test_doc.ptw, NSFilePath=/private/var/mobile/Containers/Shared/AppGroup/E6E86AC8-4E2F-45B2-9842-FB6AAE29D31E/File Provider Storage/Downloads/Bloc 2.ptw, NSUnderlyingError=0x28252c570 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}
File /private/var/mobile/Containers/Shared/AppGroup/E6E86AC8-4E2F-45B2-9842-FB6AAE29D31E/File Provider Storage/Downloads/Bloc 2.ptw exists

I tried using "url" instead of "newURL" in the fileCoordinator block.

Answer 1

The error message was misleading, the problem was with the copy destination, not the source as the message indicated. The destination Inbox folder did not exist in my app. I now copy the file "test_doc.ptw" to the Documents directory and all is fine.