iPhone Dev Resources
Create a temporary file in a safe location
While working on an application to record sounds I was in need for a temporary file location to store the recorded audio in. I wrote a simple method to return an URL to a non existing file in the temporary directory. A file with a name based on the template recording-XXXXXX.caf will be generated in the directory specified by NSTemporaryDirectory(), where XXXXXX will be replaced to create a unique name.
From the mkstemp man pages:
The mktemp() function takes the given file name template and overwrites a portion of it to
create a file name. This file name is guaranteed not to exist at the time of function invocation
and is suit-able suitable able for use by the application.
The file name generated is transformed back to a NSString and then again to a NSURL.
- (NSURL *) tmpFile {
NSString *tempFileTemplate = [NSTemporaryDirectory()
stringByAppendingPathComponent:@"recording-XXXXXX.caf"];
const char *tempFileTemplateCString =
[tempFileTemplate fileSystemRepresentation];
char *tempFileNameCString = (char *)malloc(strlen(tempFileTemplateCString) + 1);
strcpy(tempFileNameCString, tempFileTemplateCString);
int fileDescriptor = mkstemps(tempFileNameCString, 4);
// no need to keep it open
close(fileDescriptor);
if (fileDescriptor == -1) {
NSLog(@"Error while creating tmp file");
return nil;
}
NSString *tempFileName = [[NSFileManager defaultManager]
stringWithFileSystemRepresentation:tempFileNameCString
length:strlen(tempFileNameCString)];
free(tempFileNameCString);
NSLog(@"File path: %@", tempFileName);
return [NSURL fileURLWithPath:tempFileName];
}Inspired by:
http://cocoawithlove.com/2009/07/temporary-files-and-folders-in-cocoa.html
mkstemps man pages
http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man3/mktemp.3.html