writeToFile in OSX, appending to the file?

Question

I need to write some data from time to time to a file, appending to it.

Right now I have:

BOOL ok = [[NSString stringWithFormat:@\"%f\",raw] writeToF         


        

Answer 1

strcontent may be self when you put this method to a Catagory of NSString.

Answer 2

Here is an NSString category method that will append the receiver to the specified path with the specified encoding (normally NSUTF8StringEncoding).

- (BOOL) appendToFile:(NSString *)path encoding:(NSStringEncoding)enc;
{
    BOOL result = YES;
    NSFileHandle* fh = [NSFileHandle fileHandleForWritingAtPath:path];
    if ( !fh ) {
        [[NSFileManager defaultManager] createFileAtPath:path contents:nil attributes:nil];
        fh = [NSFileHandle fileHandleForWritingAtPath:path];
    }
    if ( !fh ) return NO;
    @try {
        [fh seekToEndOfFile];
        [fh writeData:[self dataUsingEncoding:enc]];
    }
    @catch (NSException * e) {
        result = NO;
    }
    [fh closeFile];
    return result;
}

Answer 3

Li'l edit to Peter N Lewis Answer:

- (BOOL) appendToFile:(NSString *)path encoding:(NSStringEncoding)enc;
{
    BOOL result = YES;
    NSFileHandle* fh = [NSFileHandle fileHandleForWritingAtPath:path];
    if ( !fh ) {
        [[NSFileManager defaultManager] createFileAtPath:path contents:nil attributes:nil];
        fh = [NSFileHandle fileHandleForWritingAtPath:path];
    }
    if ( !fh ) return NO;
    @try {
        [fh seekToEndOfFile];
        [fh writeData:[strcontent dataUsingEncoding:enc]];
    }
    @catch (NSException * e) {
        result = NO;
    }
    [fh closeFile];
    return result;
}

Call Where ever you want

 [self appendToFile:fileName encoding:NSUTF8StringEncoding];

Answer 4

One method would be to obtain a NSFileHandle using fileHandleForWritingAtPath: method, converting your NSString to NSData and then calling writeData: on your NSFileHandle after moving the file pointer to the end of the file.

Answer 5

This is my Swift version, not exactly the same, but it works. I decided not to extend String so that it could be used as an alternate to write(exportFileNameURL: URL, str: String)

fileprivate static func appendToFile(_ exportFileName: String, str: String) -> Bool {
    let result : Bool = true;
    if let fh : FileHandle = FileHandle.init(forWritingAtPath: exportFileName) {
        fh.seekToEndOfFile()
        fh.write(str.data(using: String.Encoding.utf8)!)
        fh.closeFile()
    }
    else {
        FileManager.default.createFile(atPath: exportFileName, contents: nil, attributes: nil)
        if let fh = FileHandle.init(forWritingAtPath: exportFileName) {
            fh.seekToEndOfFile()
            fh.write(str.data(using: String.Encoding.utf8)!)
            fh.closeFile()
        }
        else {
            return false;
        }
    }
    return result
}