在一个地方处理重复的错误情况

huangapple go评论87阅读模式
英文:

Handle repetitive error cases in one place

问题

我正在编写一个函数,将一个包含多个字段的结构体写入TCP连接。有没有一种方法可以像在Java中捕获异常一样,在一个地方处理错误?

我的实现如下:

func writeFrame(frame *Frame, conn net.Conn) error {
    bo := binary.BigEndian
    if err := binary.Write(conn, bo, frame.ype); err != nil {
        return err
    }
    if err := binary.Write(conn, bo, frame.id); err != nil {
        return err
    }
    if err := binary.Write(conn, bo, frame.seq); err != nil {
        return err
    }

    if err := binary.Write(conn, bo, uint32(len(frame.arg1))); err != nil {
        return err
    }
    if err := binary.Write(conn, bo, uint32(len(frame.arg2))); err != nil {
        return err
    }
    if err := binary.Write(conn, bo, uint32(len(frame.arg3))); err != nil {
        return err
    }

    var csum uint32
    if err := binary.Write(conn, bo, csum); err != nil {
        return err
    }

    if _, err := conn.Write(frame.arg1); err != nil {
        return err
    }
    if _, err := conn.Write(frame.arg2); err != nil {
        return err
    }
    if _, err := conn.Write(frame.arg3); err != nil {
        return err
    }
    return nil
}

这段代码的作用是将Frame结构体的多个字段写入TCP连接。如果在写入过程中出现错误,会在相应的位置返回错误。

英文:

I'm writing a function which writes a struct of multiple fields to a TCP connection. Is there a way to handle errors in one place like catching exception in Java?

My implementation looks like,

func writeFrame(frame *Frame, conn net.Conn) error {
bo := binary.BigEndian
if err := binary.Write(conn, bo, frame.ype); err != nil {
return err
}
if err := binary.Write(conn, bo, frame.id); err != nil {
return err
}
if err := binary.Write(conn, bo, frame.seq); err != nil {
return err
}
if err := binary.Write(conn, bo, uint32(len(frame.arg1))); err != nil {
return err
}
if err := binary.Write(conn, bo, uint32(len(frame.arg2))); err != nil {
return err
}
if err := binary.Write(conn, bo, uint32(len(frame.arg3))); err != nil {
return err
}
var csum uint32
if err := binary.Write(conn, bo, csum); err != nil {
return err
}
if _, err := conn.Write(frame.arg1); err != nil {
return err
}
if _, err := conn.Write(frame.arg2); err != nil {
return err
}
if _, err := conn.Write(frame.arg3); err != nil {
return err
}
return nil
}

答案1

得分: 2

你可以创建一个简单的类型,用于存储一系列写操作,并在遇到错误时立即停止执行。

type MyWriter struct {
    W     io.Writer
    O     binary.ByteOrder
    items []interface{}
}

func (w *MyWriter) AddWrite(value interface{}) {
    w.items = append(w.items, value)
}

// PerformWrite 执行通过 AddWrite 添加的所有写操作。
// 在遇到错误时立即中止并返回错误。
func (w *MyWriter) PerformWrites() error {
    for _, item := range w.items {
        if err := binary.Write(w.W, w.O, item); err != nil {
            return err
        }
    }
    return nil
}

有了这个结构,你的 writeFrame 函数可能如下所示:

func Write(conn net.Conn) error {
    w := MyWriter{W: conn, O: binary.BigEndian}
    // 队列化你的写操作(frame.type, frame.id, ...)
    w.AddWrite(int32(1))
    w.AddWrite(int32(2))
    w.AddWrite(int64(3))
    
    if err := w.PerformWrites(); err != nil {
        // 发生错误
        return err
    }
    return nil
}
英文:

You could create a simple type that stores a bunch of writes and executes them all at once, bailing as soon as an error is encountered.

type MyWriter struct {
W     io.Writer
O     binary.ByteOrder
items []interface{}
}
func (w *MyWriter) AddWrite(value interface{}) {
w.items = append(w.items, value)
}
// PerformWrite executes all writes that have been added via AddWrite.
// It aborts as soon as an error is encountered and returns the error.
func (w *MyWriter) PerformWrites() error {
for _, item := range w.items {
if err := binary.Write(w.W, w.O, item); err != nil {
return err
}
}
return nil
}

With this in place, your writeFrame function might look something like this:

func Write(conn net.Conn) error {
w := MyWriter{W: conn, O: binary.BigEndian}
// queue up your writes (frame.type, frame.id, ...)
w.AddWrite(int32(1))
w.AddWrite(int32(2))
w.AddWrite(int64(3))
if err := w.PerformWrites(); err != nil {
// there was an error
return err
}
return nil
}

答案2

得分: 2

你可以使用bufio.Writer来实现这个功能。如果发生任何错误,未来的写入操作将简单地返回相同的错误并被忽略。

func writeFrame(frame *Frame, conn net.Conn) error {
    bo := binary.BigEndian
    
    w := bufio.NewWriter(conn)
    
    binary.Write(w, bo, frame.ype)
    binary.Write(w, bo, frame.id)
    binary.Write(w, bo, frame.seq)
    
    binary.Write(w, bo, uint32(len(frame.arg1)))
    binary.Write(w, bo, uint32(len(frame.arg2)))
    binary.Write(w, bo, uint32(len(frame.arg3)))

    var csum uint32
    binary.Write(w, bo, csum)

    w.Write(frame.arg1)
    w.Write(frame.arg2)
    w.Write(frame.arg3)
    
    // 将未完成的数据写入 conn,并在发生错误时返回错误
    return w.Flush()
}
英文:

You can use a bufio.Writer for this. If any error occurs future Write's will simply return the same error and be ignored.

func writeFrame(frame *Frame, conn net.Conn) error {
bo := binary.BigEndian
w := bufio.NewWriter(conn)
binary.Write(w, bo, frame.ype)
binary.Write(w, bo, frame.id)
binary.Write(w, bo, frame.seq)
binary.Write(w, bo, uint32(len(frame.arg1)))
binary.Write(w, bo, uint32(len(frame.arg2)))
binary.Write(w, bo, uint32(len(frame.arg3)))
var csum uint32
binary.Write(w, bo, csum)
w.Write(frame.arg1)
w.Write(frame.arg2)
w.Write(frame.arg3)
// Write outstanding data to conn and return an error if any occured
return w.Flush()
}

1: http://golang.org/pkg/bufio/#Writer "bufio.Writer"

huangapple
  • 本文由 发表于 2015年1月13日 01:28:29
  • 转载请务必保留本文链接:https://go.coder-hub.com/27907558.html
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