Response Writer

WrapResponseWriter is for middleware authors.

Use it when middleware needs to inspect the response after the next handler runs.

func measure() zinc.Middleware {
  return func(c *zinc.Context) error {
    base := c.Writer()
    rw := zinc.WrapResponseWriter(base)
    c.SetWriter(rw)
    defer c.SetWriter(base)

    err := c.Next()

    status := rw.Status()
    bytes := rw.BytesWritten()
    written := rw.Written()

    _ = status
    _ = bytes
    _ = written
    return err
  }
}

Interface

type ResponseWriter interface {
  http.ResponseWriter
  Status() int
  BytesWritten() int
  Written() bool
}

Status() returns 200 OK until another status is written. Written() tells you whether headers or body bytes have been sent.

Optional behavior

The wrapper preserves common optional writer behavior when the underlying writer supports it:

• http.Flusher
• http.Hijacker
• io.ReaderFrom
• http.Pusher
• Unwrap() http.ResponseWriter

Use a narrow assertion when integration code needs the original writer.

if unwrapper, ok := rw.(interface{ Unwrap() http.ResponseWriter }); ok {
  base := unwrapper.Unwrap()
  _ = base
}