Question

Lots of classes have versions that work with NSStrings as a filePath or NSURLs. One example:

- (BOOL)copyItemAtPath:(NSString *)srcPath toPath:(NSString *)dstPath error:(NSError **)error
- (BOOL)copyItemAtURL:(NSURL *)srcURL toURL:(NSURL *)dstURL error:(NSError **)error

Is there an /explicit/ preference to use one over the other? I’m seeking a note in the documentation on the topic.

Answer 1

Its really up to you. However there are a lot of things that only use URL.

You can easily go from NSURL to path. but going the other direction will require some normalization.

using a path for instance with the scheme on it already will give you an improper url.

NSString *pathString = @"file://localhost/etc..../Document.txt";
NSURL *fileURL = [NSURL fileURLWithPath:pathString];// This will not work.

you can however expect the path from a URL to be the correct path if initialized correctly.

NSURL *fileURL = [NSURL URLWithString:pathString];
NSURL *sanePath = fileURL.path;

therefore you can get the correct url with 3 steps

NSURL *fileURL = [NSURL URLWithString:pathString];
NSURL *sanePath = fileURL.path;

// You can at this point use the Path and expect it will be correct.

fileURL = [NSURL fileURLWithPath:sanePath];

// You can at this point use fileURL and know it will be a correct fileURL with file://.

alternatively you can check the scheme to see if it is correct. but this is a problem I ran into with AVAsset because it will not load an NSURL from the path alone. It must be a fileURL

Good luck. 🙂