记录 http.ResponseWriter 内容

Question

前提：我发现了一个类似的问题，但在我的案例中不起作用，所以请不要将其标记为重复。

我在 Go 中有一个 HTTP 服务器，我创建了一个 中间件 来记录请求、响应时间，我也想记录响应。

我在包 log 下的一个名为 HTTPRequest 的函数中使用了 httputil.DumpRequest。我怎样才能正确地从 w http.ResponseWriter 获得响应 body 和状态以及 headers 并将它们与其他数据一起记录？

我的问题是：我想拦截响应 Headers、状态和 Body 并与请求和响应时间一起记录

代码如下：

log "core/logger"
...
func RequestLoggerMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        start := time.Now()

        defer func() {
            log.Info(
                fmt.Sprintf(
                    "[Request: %s] [Execution time: %v] [Response: %s]",
                    log.HTTPRequest(r),
                    time.Since(start),
                    // RESPONSE DATA HERE !!!!!!!
                ))
        }()
        next.ServeHTTP(w, r)
    })
}

Answer 1

您需要包装 ResponseWriter 以捕获响应数据。

type ResponseWriterWrapper struct {
  w           http.ResponseWriter
  body        bytes.Buffer
  statusCode  int
}

func (i *ResponseWriterWrapper) Write(buf []byte) (int, error) {
  i.body.Write(buf)
  return i.w.Write(buf)
}

func (i *ResponseWriterWrapper) WriteHeader(statusCode int) {
  i.statusCode = statusCode
  i.w.WriteHeader(statusCode)
}

func (i *ResponseWriterWrapper) String() {
  var buf bytes.Buffer

  buf.WriteString("Response:")

  buf.WriteString("Headers:")
  for k, v := range i.w.Header() {
    buf.WriteString(fmt.Sprintf("%s: %v", k, v))
  }

  buf.WriteString(fmt.Sprintf("Status Code: %d", i.statusCode))

  buf.WriteString("Body")
  buf.WriteString(i.body.String())
}

将包装器传递给 ServeHTTP 并记录捕获的响应数据。

func RequestLoggerMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        start := time.Now()
        rww := ResponseWriterWrapper{ w: w }

        defer func() {
            log.Info(
                fmt.Sprintf(
                    "[Request: %s] [Execution time: %v] [Response: %s]",
                    log.HTTPRequest(r),
                    time.Since(start),
                    log.Info(rww.String())
                ))
        }()
        next.ServeHTTP(rww, r)
    })
}

Answer 2

谢谢，@Sivachandran 的回复。它几乎是完美的，只是它没有实现 http.ResponseWriter 因为指针。

为了完整起见，我post在这里给出了正确的解决方案代码，因为很难找到关于它的任何文档，即使这道题被打了负分。

Whosebug 是交流问题的好地方，在我看来，这是一个 非常好的问题，无论是对于一个中等水平的 Golang 程序员，所以它 根本不值得负分！

这就是解决方案，享受：

// RequestLoggerMiddleware is the middleware layer to log all the HTTP requests
func RequestLoggerMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        start := time.Now()
        rww := NewResponseWriterWrapper(w)
        w.Header()
        defer func() {
            log.Info(
                fmt.Sprintf(
                    "[Request: %s] [Execution time: %v] [Response: %s]",
                    log.HTTPRequest(r),
                    time.Since(start),
                    rww.String(),
                ))
        }()
        next.ServeHTTP(rww, r)
    })
}

// ResponseWriterWrapper struct is used to log the response
type ResponseWriterWrapper struct {
    w          *http.ResponseWriter
    body       *bytes.Buffer
    statusCode *int
}

// NewResponseWriterWrapper static function creates a wrapper for the http.ResponseWriter
func NewResponseWriterWrapper(w http.ResponseWriter) ResponseWriterWrapper {
    var buf bytes.Buffer
    var statusCode int = 200
    return ResponseWriterWrapper{
        w:          &w,
        body:       &buf,
        statusCode: &statusCode,
    }
}

func (rww ResponseWriterWrapper) Write(buf []byte) (int, error) {
    rww.body.Write(buf)
    return (*rww.w).Write(buf)
}

// Header function overwrites the http.ResponseWriter Header() function
func (rww ResponseWriterWrapper) Header() http.Header {
    return (*rww.w).Header()

}

// WriteHeader function overwrites the http.ResponseWriter WriteHeader() function
func (rww ResponseWriterWrapper) WriteHeader(statusCode int) {
    (*rww.statusCode) = statusCode
    (*rww.w).WriteHeader(statusCode)
}

func (rww ResponseWriterWrapper) String() string {
    var buf bytes.Buffer

    buf.WriteString("Response:")

    buf.WriteString("Headers:")
    for k, v := range (*rww.w).Header() {
        buf.WriteString(fmt.Sprintf("%s: %v", k, v))
    }

    buf.WriteString(fmt.Sprintf(" Status Code: %d", *(rww.statusCode)))

    buf.WriteString("Body")
    buf.WriteString(rww.body.String())
    return buf.String()
}

记录 http.ResponseWriter 内容

log http.ResponseWriter content

logging

middleware

go