Zip from command line - how to trim path elements - cocoa

Question

I'm executing a zip command from within my app using NSTask. It's passed as arguments some paths which point to the files/folders to be zipped.
The problem is that without the -j option, the final zip ends up with absurd filepaths inside the zip, (like "/private/var/folders/A5/A5CusLQaEo4mop-reb-SYE+++TI/-Tmp-/9101A216-5A6A-4CD6-A477-E4B86E007476-51228-00014BCB9514323F/myfile.rtf"). However, if I add the -j option, then I constantly run into name collisions if any file anywhere deep inside a nested folder has
I've tried setting the path before executing the NSTask:
[[NSFileManager defaultManager] changeCurrentDirectoryPath:path];
In the hope that the documentation for zip was telling the truth:
By default, zip will store the full path
(relative to the current directory)
But this did not work as expected. Adjusting settings of -j and -p and -r simply produces the above mentioned problems in different combinations.
QUESTION:
How can I take a set of directories like
/some/long/path/sub1/file1.txt
/some/long/path/sub2/file1.txt
and zip them into a zip whose contents are
/sub1/file1.txt
/sub2/file1.txt
Thanks for any advice on the subtleties of zip.
-----EDIT
One other thing I forgot to add is that the original directory being passed is "path", so the desired outcome is also to my mind the expected outcome.

Answer 1

Instead of
[[NSFileManager defaultManager] changeCurrentDirectoryPath:path];
use -[NSTask setCurrentDirectoryPath:] prior to launching the task. For example:
NSString *targetZipPath = #"/tmp/foo.zip";
NSArray *args = [NSArray arrayWithObjects:#"-r", targetZipPath,
#"sub1", #"sub2", nil];
NSTask *task = [[NSTask alloc] init];
[task setLaunchPath:#"/usr/bin/zip"];
[task setArguments:args];
// set path to be the parent directory of sub1, sub2
[task setCurrentDirectoryPath:path];
…

Answer 2

This is not a universal solution, in that it won't handle multiple directories well, but the solution I'm using for a single directory of unknown contents (ie, mixed files/folders/bundles) is to enumerate the contents of the directory and add them individually as arguments to zip, rather than simply zipping the entire directory at once.
Specifically:
+ (BOOL)zipDirectory:(NSURL *)directoryURL toArchive:(NSString *)archivePath;
{
//Delete existing zip
if ( [[NSFileManager defaultManager] fileExistsAtPath:archivePath] ) {
[[NSFileManager defaultManager] removeItemAtPath:archivePath error:nil];
}
//Specify action
NSString *toolPath = #"/usr/bin/zip";
//Get directory contents
NSArray *pathsArray = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:[directoryURL path] error:nil];
//Add arguments
NSMutableArray *arguments = [[[NSMutableArray alloc] init] autorelease];
[arguments insertObject:#"-r" atIndex:0];
[arguments insertObject:archivePath atIndex:0];
for ( NSString *filePath in pathsArray ) {
[arguments addObject:filePath]; //Maybe this would even work by specifying relative paths with ./ or however that works, since we set the working directory before executing the command
//[arguments insertObject:#"-j" atIndex:0];
}
//Switch to a relative directory for working.
NSString *currentDirectory = [[NSFileManager defaultManager] currentDirectoryPath];
[[NSFileManager defaultManager] changeCurrentDirectoryPath:[directoryURL path]];
//NSLog(#"dir %#", [[NSFileManager defaultManager] currentDirectoryPath]);
//Create
NSTask *task = [[[NSTask alloc] init] autorelease];
[task setLaunchPath:toolPath];
[task setArguments:arguments];
//Run
[task launch];
[task waitUntilExit];
//Restore normal path
[[NSFileManager defaultManager] changeCurrentDirectoryPath:currentDirectory];
//Update filesystem
[[NSWorkspace sharedWorkspace] noteFileSystemChanged:archivePath];
return ([task terminationStatus] == 0);
}
Again, I make no claims this is bulletproof (and would love improvements) but it does work at correctly zipping any single folder.