是否有API可以从读取器读取行，但可以限制返回行的长度？

Question

The prototype would be:

 (reader *Reader) ReadLineWithMaxLength (delim byte, max int) (line []byte, err error)

It returns a line when either the delim is found or max length is reached.

Answer 1

I don't think there is a direct function, but implementing one using io.LimitReader is straightforward.

func ReadLimitedLine(r io.Reader, delim byte, max int64) ([]byte, error) {
    l, err := bufio.NewReader(io.LimitReader(r, max)).ReadBytes(delim)
    if err != nil && err != io.EOF {
        return nil, err
    }

    // ReadBytes includes the delimiter in return value
    return bytes.TrimSuffix(l, []byte{delim}), nil
}