Permalink
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
114 lines (95 sloc) 2.75 KB
package negroni
import (
"bufio"
"fmt"
"net"
"net/http"
)
// ResponseWriter is a wrapper around http.ResponseWriter that provides extra information about
// the response. It is recommended that middleware handlers use this construct to wrap a responsewriter
// if the functionality calls for it.
type ResponseWriter interface {
http.ResponseWriter
http.Flusher
// Status returns the status code of the response or 0 if the response has
// not been written
Status() int
// Written returns whether or not the ResponseWriter has been written.
Written() bool
// Size returns the size of the response body.
Size() int
// Before allows for a function to be called before the ResponseWriter has been written to. This is
// useful for setting headers or any other operations that must happen before a response has been written.
Before(func(ResponseWriter))
}
type beforeFunc func(ResponseWriter)
// NewResponseWriter creates a ResponseWriter that wraps an http.ResponseWriter
func NewResponseWriter(rw http.ResponseWriter) ResponseWriter {
nrw := &responseWriter{
ResponseWriter: rw,
}
if _, ok := rw.(http.CloseNotifier); ok {
return &responseWriterCloseNotifer{nrw}
}
return nrw
}
type responseWriter struct {
http.ResponseWriter
status int
size int
beforeFuncs []beforeFunc
}
func (rw *responseWriter) WriteHeader(s int) {
rw.status = s
rw.callBefore()
rw.ResponseWriter.WriteHeader(s)
}
func (rw *responseWriter) Write(b []byte) (int, error) {
if !rw.Written() {
// The status will be StatusOK if WriteHeader has not been called yet
rw.WriteHeader(http.StatusOK)
}
size, err := rw.ResponseWriter.Write(b)
rw.size += size
return size, err
}
func (rw *responseWriter) Status() int {
return rw.status
}
func (rw *responseWriter) Size() int {
return rw.size
}
func (rw *responseWriter) Written() bool {
return rw.status != 0
}
func (rw *responseWriter) Before(before func(ResponseWriter)) {
rw.beforeFuncs = append(rw.beforeFuncs, before)
}
func (rw *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
hijacker, ok := rw.ResponseWriter.(http.Hijacker)
if !ok {
return nil, nil, fmt.Errorf("the ResponseWriter doesn't support the Hijacker interface")
}
return hijacker.Hijack()
}
func (rw *responseWriter) callBefore() {
for i := len(rw.beforeFuncs) - 1; i >= 0; i-- {
rw.beforeFuncs[i](rw)
}
}
func (rw *responseWriter) Flush() {
flusher, ok := rw.ResponseWriter.(http.Flusher)
if ok {
if !rw.Written() {
// The status will be StatusOK if WriteHeader has not been called yet
rw.WriteHeader(http.StatusOK)
}
flusher.Flush()
}
}
type responseWriterCloseNotifer struct {
*responseWriter
}
func (rw *responseWriterCloseNotifer) CloseNotify() <-chan bool {
return rw.ResponseWriter.(http.CloseNotifier).CloseNotify()
}