在go中读取US-ASCII文件

currently I try to read a us-ascii file into golang, but everytime I do so, every special sign, like Ä Ö Ü ß gets replaced with a ? or on my database with the special sign ?.

Is there anything I could do to prevent it?

Here is how I read my file:

file, err := os.Open(path)
if err != nil {
    return err
}
var lines []string
r := bufio.NewReader(file)
for {
    line, err := r.ReadBytes('
')
    if err != nil {
        break
    }
    lines = append(lines, string(line))
}
fmt.Println(strings.Join(lines, ""))
index.Content = strings.Join(lines, "")

Since the letters Ä Ö Ü ß doesn't exist in US-ASCII, I would make an educated guess that you are actually dealing with the Latin-1 (ISO-8859-1) encoding.

Converting from Latin-1 can be done like this:

runes := make([]rune, len(line))
for i, b := range line {
    runes[i] = rune(b)
}
lines = append(lines, string(runes))

Edit:

The example is not optimized, but it shows how a Latin-1 byte can be stored in a rune as the values of Latin-1 corresponds directly to the Unicode code point. The actual encoding into UTF-8 is then done when converting []rune to string.