Xcode + Swift + OS X : How do I read a file?

I’d suggest creating and testing with a command-line tool app and not a GUI tool to start with, as that involves contending with fewer pieces.

Here’s a CSV-related file-reading thread with an example: https://developer.apple.com/forums/thread/90293

XChrisAH wrote:

Etresoft,

NSOpenPanel worked. It appears to pull the document over into the sandbox and allow me to read it.

Implementation was relatively easy.

That's good to hear.

Technically speaking, it doesn't put the document into the sandbox, it pokes a hole into the sandbox, respecting your user's intent, so that your sandboxed app can read the file.

However, I strongly suggest you read my rant about CSV that I just posted in this other thread. It's OK if you are just learning, but you never want to attempt to read CSV on your own. It seems simple, but it is practically impossible in the real world. If you wanted to use something that had real-world utility, I would suggest you save your input file in JSON format instead. JSON is a similar garbage file format, but it is loved by all the hip kids these days. Reading JSON using a strongly typed language like Swift poses some interesting problems.

I don’t think your suggestion, or MrHoffman’s above, will work by default. They both use a full file path. That is the correct solution due to the ambiguous nature of the “current directory” in a GUI app. But the default settings for new projects in Xcode have the Sandbox enabled, which will not allow access to most user paths. Xcode is just not beginner-friendly.

I have found when I save a file that it usually goes into the binary folder for the new application. You can then store files there and they should be found. Note that it has been a while (pre-sandbox) since I tried this.

Keith Barkley wrote:

I have found when I save a file that it usually goes into the binary folder for the new application. You can then store files there and they should be found. Note that it has been a while (pre-sandbox) since I tried this.

To tell you the truth, I'm not even sure about the behaviour of NSOpenPanel with respect to the file-read entitlement. I have an app in the store right now that doesn't have any file-read entitlements, yet it still reads system files. I don't need NSOpenPanel or an entitlement to read them. It's tricky. My primary app right now is on iOS. There too, I can read files (and write) files with no entitlement. It's just the Mac with all these legacy APIs that makes things so tricky. I would not recommend anyone start developing on macOS these days.

You would need to create a document-based app or use an NSOpenPanel to get a URL that you can read.

Your desktop is probably not the current directory. Try a full path. (I have been known to first save a file to see where it goes. Then you know the current directory.)