dongwa3808 2018-12-22 10:33
浏览 56
已采纳

从扫描仪转换为io.Reader的惯用方式

I recently ran into this issue of how to read from a CSV file, apply some transformation to every line and write to a HTTP request.

The problem I was faced with was how to convert from a line-by-line reader which returns an arbitrary number of bytes (like a Scanner) to a byte reader, which returns a fixed amount of bytes at every call to Read().

The best solution I came up with is to build a custom io.Reader that would read from the Scanner and buffer bytes locally if they wouldn't fit. Then the buffered bytes would be returned on the next call to Read().

This is what I came up with: https://gist.github.com/paulsc/6a0bf30a2a8d898f7a8086aedf6af1e1

Intuitively, this feels like the wrong solution, because the code seems like a fairly low-level solution that might already be in the standard library.

Is there a better way, more idiomatic to do this with standard go components ?

  • 写回答

1条回答 默认 最新

  • douxing9641 2018-12-22 13:06
    关注

    A simple method is using io.Pipe.

    func ScannerToReader(scanner *bufio.Scanner) io.Reader {
        reader, writer := io.Pipe()
    
    
        go func() {
            defer writer.Close()
            for scanner.Scan() {
                writer.Write(scanner.Bytes())
            }
        }()
    
        return reader
    }
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥50 深度学习运行代码直接中断
  • ¥15 关于#单片机#的问题,请各位专家解答!
  • ¥15 关于#单片机#的问题,请各位专家解答!
  • ¥20 需要完整的共散射点成像代码
  • ¥15 编写vba代码实现数据录入工作
  • ¥15 做过TCL海信电视小米电视相关影视会员软件私我
  • ¥15 Mapreduce是正常的,在运行其他jar包时并没有任何问题,只是在做LogCount.jar 时出的问题。如图所示
  • ¥15 ImportError: DLL load failed while importing _iterative: 找不到指定的模块。
  • ¥15 如何通过交互分析得出某高危患者对放疗获益更多
  • ¥15 相关性分析中,p<0.05, r=0.29,怎么评价相关性呢