What is the encoding for URL bookmarks stored as NSData? - macos

What is the best way to get the path from the NSData bookmark object, if the bookmark will not resolve?
Normally, you just resolve the bookmark, you get a URL, and off you go. But if the bookmark is to an NFS mount that is not currently present, it won't resolve. So now I have an NSData pointing somewhere that won't resolve, but I don't know where it points.
Here is the code block I have that loads the bookmarks, tries to resolve them, and attempts to decode the NSData if the resolve fails, but I can't figure out the encoding - is this even possible?
NSError* error = [[NSError alloc] init];
NSURL* resolvedURL = [NSURL URLByResolvingBookmarkData:bookmarkData
options:NSURLBookmarkResolutionWithSecurityScope | NSURLBookmarkResolutionWithoutUI
relativeToURL:nil
bookmarkDataIsStale:NULL
error:&error];
if (resolvedURL) {
// do some stuff
...
} else {
NSString* msg = [NSString stringWithFormat:#"Error Resolving Bookmark: %#", error];
NSLog(msg);
// the below certainly doesn't get me a path from the bookmark, any idea what will?
// NSString* path = [[NSString alloc] initWithData:bookmarkData encoding:NSUTF32StringEncoding];
}

I never did figure out the encoding, but I found a workaround.
Originally, I encoded the sandboxed NSURLs into NSData objects, and then stored those as an NSArray in NSDefaults. Therefore, I had no way to determine the path for the NSData, unless it would resolve.
The workaround was to change the design - now I encode the sandboxed NSURL, store it as an object into an NSDictionary with the key being the URL path, and store the NSDictionary in NSDefaults.
With this approach, I can easily retrieve the NSData for any given path, even if it will not resolve.

Related

NSURLThumbnailDictionaryKey empty for local file

I want to get a thumbnail representation of a file I have to display in my app. I'm using NSURL here:
NSDictionary *thumbnails = nil;
BOOL success = [fileURL getResourceValue:&thumbnails
forKey:NSURLThumbnailDictionaryKey
error: &error];
This works fine if I am connected to iCloud, and the URL is a link to a file stored in iCloud. The fileURL is something like:
file:///Users/me/Library/Mobile%20Documents/BJXXGLR9R3~com~myapp~icloud/FileStorage/contact-page%20copy.png
If I use the same code with a NSURL pointing to a local file, however, the thumbnails dictionary is empty.
Here is an example of the URL in this case:
file:///Users/me/Library/Containers/com.mycompany.mymacapp/Data/Library/Application%20Support/com.mycompany.mymacapp/FileStorage/Bn4VaCnCUAEJjLb.png-large.png
Is this API for getResourceValue not supposed to work with locally stored files? Or am I doing something wrong?
This is part of the API. Furthermore you should use a File coordinator while working with files coming from iCloud:
[url startAccessingSecurityScopedResource];
NSFileCoordinator *coordinator = [[NSFileCoordinator alloc] init];
__block NSError *error;
[coordinator coordinateReadingItemAtURL:url options:0 error:&error byAccessor:^(NSURL *newURL) {
[newURL getResourceValue:&image forKey:NSURLThumbnailDictionaryKey error:&error];
}];
[url stopAccessingSecurityScopedResource];

dictionaryWithContentsOfFile and Sandbox

I've created a mac app that load a xml file from an user selected folder, and after using the app, the user saves a customized file (.adgf)
When i try to load the .adgf file (that is a plist file) that has the xml path within one record i call
dictionaryWithContentsOfFile but it return me a "nil". I think the problem is the sandbox (sometime it works sometime not). The string path is correct.
Maybe when the user load the xml file should i save within of particular app "Document folder"?
Edit:
I'm trying right now the Bookmark Data solution and I retraive a NSURL but it doen't work. The code I'm using is this:
- (NSData *)bookmarkFromURL:(NSURL *)url {
NSError *error = nil;
NSData *bookmark = [url bookmarkDataWithOptions:NSURLBookmarkCreationWithSecurityScope
includingResourceValuesForKeys:NULL
relativeToURL:NULL
error:&error];
if (error) {
NSLog(#"Error creating bookmark for URL (%#): %#", url, error);
[NSApp presentError:error];
}
return bookmark;
}
- (NSURL *)urlFromBookmark:(NSData *)bookmark {
NSURL *url = [NSURL URLByResolvingBookmarkData:bookmark
options:NSURLBookmarkResolutionWithSecurityScope
relativeToURL:NULL
bookmarkDataIsStale:NO
error:NULL];
return url;
}
After the user stores the file you should take the bookmark data from the URL using
-[NSURL bookmarkDataWithOptions: includingResourceValuesForKeys: relativeToURL: error:]
Use NSURLBookmarkCreationWithSecurityScope for the options.
This NSData object should be stored somewhere (plist?) and when you want to read the file again in a later session you can create a sandbox compliant NSURL from the bookmark data using +[NSURL
URLByResolvingBookmarkData:options:relativeToURL:bookmarkDataIsStale:error:]

Mas OS X: error in contentsOfDirectoryAtURL method

I have a trouble, I have a folder url, folder, that stored on that url path is exist and it's ok. Problem is that contentsOfDirectoryAtURL:includingPropertiesForKeys:options:error: returns with an error.
My NSURL to folder is NSString, that made from another method that take NSURL and save it as absoluteString object.
Here is my code:
NSURL *folderURL = [NSURL fileURLWithPath:folderPathString isDirectory:YES];
if ([folderURL isFileURL]) {
NSLog(#"it's file"); // I see this in console
}
NSError *error;
// array of NSURL objects
NSArray *contentOfFolder = [[NSFileManager defaultManager] contentsOfDirectoryAtURL:folderURL
includingPropertiesForKeys:#[NSURLContentModificationDateKey,NSURLFileResourceTypeKey, NSURLLocalizedNameKey]
options:NSDirectoryEnumerationSkipsHiddenFiles
error:&error];
if (error) {
NSLog(#"%#",error);
}
This is a part of my method, in console, I see an error:
Error Domain=NSCocoaErrorDomain Code=260 "The file “myFolder” couldn’t be opened because there is no such file." UserInfo=0x10051b0a0 {NSURL=file:/localhost/Users/myUser/myRootFolder/myFolder/ -- file://localhost/Users/myUser/Library/Developer/Xcode/DerivedData/myProject-algooymkavrtmlchwnlbrmvcbvzj/Build/Products/Debug/, NSFilePath=/Users/myUser/Library/Developer/Xcode/DerivedData/myProject-algooymkavrtmlchwnlbrmvcbvzj/Build/Products/Debug/file:/localhost/Users/myUser/myRootFolder/myFolder, NSUnderlyingError=0x100526f40 "The operation couldn’t be completed. No such file or directory"}
I don't understand why I get this error. How I can get No such file or directory error, if this directory exist?!
EDIT
I found that after method fileURLWithPath:isDirectory: my folder url looks strange, when I look at it with NSLog.
NSLog(#"folder url %#",folderURL);
output:
folder url file:/localhost/Users/myUser/myRootFolder/myFolder/
-- file://localhost/Users/myUser/Library/Developer/Xcode/DerivedData/myProject-algooymkavrtmlchwnlbrmvcbvzj/Build/Products/Debug/
Why the second part is appear? (part that starts with -- file://localhost/Users/myUser/Library/...). I think problem with this but what I do wrong? Is method fileURLWithPath:isDirectory: don't acceptable for my purposes?
The folderPathString in
NSURL *folderURL = [NSURL fileURLWithPath:folderPathString isDirectory:YES];
must be a simple path, e.g. "/path/to/dir". In your case, it is a string URL "file://localhost/path/to/dir", which is wrong.
I assume that folderPathString is created from some NSURL using
folderPathString = [anURL absoluteString];
This is wrong and should be
folderPathString = [anURL path];
It might also be possible to avoid the conversion from URL to string and back to URL
altogether.

Can temporary NSManagedObjectID be archived?

For permanent NSManagedObjectID, I know you can archive their URIRepresentation and get back the NSManagedObjectID later using the persistant store.
NSURL *uriRep = [objectId URIRepresentation];
NSPersistentStoreCoordinator *psc = ...
NSManagedObjectContext *context = ...
NSManagedObjectID *myID = [psc managedObjectIDForURIRepresentation:uriRep];
NSManagedObject *myObj = [context objectWithID:myID];
However, what if the ID is temporary? Is there a way to still turn it into NSString or NSData and get it back later, bypassing the persistent store, and use it directly with the context? This could be useful for some temporary objects.

What do I do with NSData?

I am trying to send email programmatically... I have this line of code:
_mail.AddAttachmentData(nsd,"text/plain", filePath);
and I haven't a clue what goes into NSData... I tried taking the string that I was writing to a file, but apparently that doesn't work either. I believe it is preventing me from doing a good sendmail.
NSData is a class type. See here:
http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSData_Class/Reference/Reference.html
You'll probably want to construct your NSData object using something like this:
NSString *myFilePath = [[NSBundle mainBundle] pathForResource:#"MyFile" ofType:#"txt"];
NSData *myData = [NSData dataWithContentsOfFile:myFilePath];
Then pass that in as the NSData object.

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