Writing a csv from app, Cocoa error 513 - ios

Question

I am creating an iPhone app that writes to a CSV file. It seems the most simple method of this would be to add to an NSMutableString from an array. The code I have should be working expect I keep getting Cocoa error 513
The code is:
NSArray *firstArray=[NSArray arrayWithObjects:#"A",#"b",nil];
NSMutableString *csv = [NSMutableString stringWithString:#"Strings"];
NSUInteger count = [firstArray count];
for (NSUInteger i=0; i<count; i++ ) {
[csv appendFormat:#"\n %#",
[firstArray objectAtIndex:i]
];
}
NSString *yourFileName = #"leads.csv";
NSError *error;
BOOL res = [csv writeToFile:yourFileName atomically:YES encoding:NSUTF8StringEncoding error:&error];
if (!res) {
NSLog(#"Error %# while writing to file %#", [error localizedDescription], yourFileName );
}
Thank you so much!

Answer 1

It is most likely because you are writing to a file location that you do not have permission to write.
Cocoa error 513 translates to the error NSFileWriteNoPermissionError.
Typically, this occurs when someone tries to write to a file within the applications bundle. You cannot modify the contents of a compiled app's bundle folder. This is because the bundle is a signed, compiled application.
When you eventually distribute the app through the iTunes App Store, the application has a digital signature that validates the contents of the app. This signature is generated at compile time and once signed, Apple does not want anyone tampering with the contents.
Make sure you are writing to an appropriate location, like Documents, Temp and Cache using something like the following:
NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:#"subFolder"];
NSString *filePath = [dataPath stringByAppendingPathComponent:#"fileName.csv"];
if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
{
[[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:&error]; //Create folder
}
BOOL res = [csv writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error];
if (!res) {
NSLog(#"Error %# while writing to file %#", [error localizedDescription], yourFileName );
}
These folders are only accessible to your app. No other app can access the contents of these folders. (Likewise, your app cannot access another app's folders.)