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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package httptest
import (
"bytes"
"fmt"
"io/ioutil"
"net/http"
"net/textproto"
"strconv"
"strings"
"golang.org/x/net/http/httpguts"
)
// ResponseRecorder is an implementation of http.ResponseWriter that
// records its mutations for later inspection in tests.
type ResponseRecorder struct {
// Code is the HTTP response code set by WriteHeader.
//
// Note that if a Handler never calls WriteHeader or Write,
// this might end up being 0, rather than the implicit
// http.StatusOK. To get the implicit value, use the Result
// method.
Code int
// HeaderMap contains the headers explicitly set by the Handler.
// It is an internal detail.
//
// Deprecated: HeaderMap exists for historical compatibility
// and should not be used. To access the headers returned by a handler,
// use the Response.Header map as returned by the Result method.
HeaderMap http.Header
// Body is the buffer to which the Handler's Write calls are sent.
// If nil, the Writes are silently discarded.
Body *bytes.Buffer
// Flushed is whether the Handler called Flush.
Flushed bool
result *http.Response // cache of Result's return value
snapHeader http.Header // snapshot of HeaderMap at first Write
wroteHeader bool
}
// NewRecorder returns an initialized ResponseRecorder.
func NewRecorder() *ResponseRecorder {
return &ResponseRecorder{
HeaderMap: make(http.Header),
Body: new(bytes.Buffer),
Code: 200,
}
}
// DefaultRemoteAddr is the default remote address to return in RemoteAddr if
// an explicit DefaultRemoteAddr isn't set on ResponseRecorder.
const DefaultRemoteAddr = "1.2.3.4"
// Header implements http.ResponseWriter. It returns the response
// headers to mutate within a handler. To test the headers that were
// written after a handler completes, use the Result method and see
// the returned Response value's Header.
func (rw *ResponseRecorder) Header() http.Header {
m := rw.HeaderMap
if m == nil {
m = make(http.Header)
rw.HeaderMap = m
}
return m
}
// writeHeader writes a header if it was not written yet and
// detects Content-Type if needed.
//
// bytes or str are the beginning of the response body.
// We pass both to avoid unnecessarily generate garbage
// in rw.WriteString which was created for performance reasons.
// Non-nil bytes win.
func (rw *ResponseRecorder) writeHeader(b []byte, str string) {
if rw.wroteHeader {
return
}
if len(str) > 512 {
str = str[:512]
}
m := rw.Header()
_, hasType := m["Content-Type"]
hasTE := m.Get("Transfer-Encoding") != ""
if !hasType && !hasTE {
if b == nil {
b = []byte(str)
}
m.Set("Content-Type", http.DetectContentType(b))
}
rw.WriteHeader(200)
}
// Write implements http.ResponseWriter. The data in buf is written to
// rw.Body, if not nil.
func (rw *ResponseRecorder) Write(buf []byte) (int, error) {
rw.writeHeader(buf, "")
if rw.Body != nil {
rw.Body.Write(buf)
}
return len(buf), nil
}
// WriteString implements io.StringWriter. The data in str is written
// to rw.Body, if not nil.
func (rw *ResponseRecorder) WriteString(str string) (int, error) {
rw.writeHeader(nil, str)
if rw.Body != nil {
rw.Body.WriteString(str)
}
return len(str), nil
}
// WriteHeader implements http.ResponseWriter.
func (rw *ResponseRecorder) WriteHeader(code int) {
if rw.wroteHeader {
return
}
rw.Code = code
rw.wroteHeader = true
if rw.HeaderMap == nil {
rw.HeaderMap = make(http.Header)
}
rw.snapHeader = rw.HeaderMap.Clone()
}
// Flush implements http.Flusher. To test whether Flush was
// called, see rw.Flushed.
func (rw *ResponseRecorder) Flush() {
if !rw.wroteHeader {
rw.WriteHeader(200)
}
rw.Flushed = true
}
// Result returns the response generated by the handler.
//
// The returned Response will have at least its StatusCode,
// Header, Body, and optionally Trailer populated.
// More fields may be populated in the future, so callers should
// not DeepEqual the result in tests.
//
// The Response.Header is a snapshot of the headers at the time of the
// first write call, or at the time of this call, if the handler never
// did a write.
//
// The Response.Body is guaranteed to be non-nil and Body.Read call is
// guaranteed to not return any error other than io.EOF.
//
// Result must only be called after the handler has finished running.
func (rw *ResponseRecorder) Result() *http.Response {
if rw.result != nil {
return rw.result
}
if rw.snapHeader == nil {
rw.snapHeader = rw.HeaderMap.Clone()
}
res := &http.Response{
Proto: "HTTP/1.1",
ProtoMajor: 1,
ProtoMinor: 1,
StatusCode: rw.Code,
Header: rw.snapHeader,
}
rw.result = res
if res.StatusCode == 0 {
res.StatusCode = 200
}
res.Status = fmt.Sprintf("%03d %s", res.StatusCode, http.StatusText(res.StatusCode))
if rw.Body != nil {
res.Body = ioutil.NopCloser(bytes.NewReader(rw.Body.Bytes()))
} else {
res.Body = http.NoBody
}
res.ContentLength = parseContentLength(res.Header.Get("Content-Length"))
if trailers, ok := rw.snapHeader["Trailer"]; ok {
res.Trailer = make(http.Header, len(trailers))
for _, k := range trailers {
k = http.CanonicalHeaderKey(k)
if !httpguts.ValidTrailerHeader(k) {
// Ignore since forbidden by RFC 7230, section 4.1.2.
continue
}
vv, ok := rw.HeaderMap[k]
if !ok {
continue
}
vv2 := make([]string, len(vv))
copy(vv2, vv)
res.Trailer[k] = vv2
}
}
for k, vv := range rw.HeaderMap {
if !strings.HasPrefix(k, http.TrailerPrefix) {
continue
}
if res.Trailer == nil {
res.Trailer = make(http.Header)
}
for _, v := range vv {
res.Trailer.Add(strings.TrimPrefix(k, http.TrailerPrefix), v)
}
}
return res
}
// parseContentLength trims whitespace from s and returns -1 if no value
// is set, or the value if it's >= 0.
//
// This a modified version of same function found in net/http/transfer.go. This
// one just ignores an invalid header.
func parseContentLength(cl string) int64 {
cl = textproto.TrimString(cl)
if cl == "" {
return -1
}
n, err := strconv.ParseUint(cl, 10, 63)
if err != nil {
return -1
}
return int64(n)
}