minio/internal/http/response-recorder.go

130 lines
3.7 KiB
Go

// Copyright (c) 2015-2022 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package http
import (
"bytes"
"fmt"
"io"
"net/http"
"time"
)
// ResponseRecorder - is a wrapper to trap the http response
// status code and to record the response body
type ResponseRecorder struct {
http.ResponseWriter
StatusCode int
// Log body of 4xx or 5xx responses
LogErrBody bool
// Log body of all responses
LogAllBody bool
TimeToFirstByte time.Duration
StartTime time.Time
// number of bytes written
bytesWritten int
// number of bytes of response headers written
headerBytesWritten int
// Internal recording buffer
headers bytes.Buffer
body bytes.Buffer
// Indicate if headers are written in the log
headersLogged bool
}
// NewResponseRecorder - returns a wrapped response writer to trap
// http status codes for auditing purposes.
func NewResponseRecorder(w http.ResponseWriter) *ResponseRecorder {
return &ResponseRecorder{
ResponseWriter: w,
StatusCode: http.StatusOK,
StartTime: time.Now().UTC(),
}
}
func (lrw *ResponseRecorder) Write(p []byte) (int, error) {
if !lrw.headersLogged {
// We assume the response code to be '200 OK' when WriteHeader() is not called,
// that way following Golang HTTP response behavior.
lrw.WriteHeader(http.StatusOK)
}
n, err := lrw.ResponseWriter.Write(p)
lrw.bytesWritten += n
if lrw.TimeToFirstByte == 0 {
lrw.TimeToFirstByte = time.Now().UTC().Sub(lrw.StartTime)
}
if (lrw.LogErrBody && lrw.StatusCode >= http.StatusBadRequest) || lrw.LogAllBody {
// Always logging error responses.
lrw.body.Write(p)
}
if err != nil {
return n, err
}
return n, err
}
// Write the headers into the given buffer
func (lrw *ResponseRecorder) writeHeaders(w io.Writer, statusCode int, headers http.Header) {
n, _ := fmt.Fprintf(w, "%d %s\n", statusCode, http.StatusText(statusCode))
lrw.headerBytesWritten += n
for k, v := range headers {
n, _ := fmt.Fprintf(w, "%s: %s\n", k, v[0])
lrw.headerBytesWritten += n
}
}
// BodyPlaceHolder returns a dummy body placeholder
var BodyPlaceHolder = []byte("<BODY>")
// Body - Return response body.
func (lrw *ResponseRecorder) Body() []byte {
// If there was an error response or body logging is enabled
// then we return the body contents
if (lrw.LogErrBody && lrw.StatusCode >= http.StatusBadRequest) || lrw.LogAllBody {
return lrw.body.Bytes()
}
// ... otherwise we return the <BODY> place holder
return BodyPlaceHolder
}
// WriteHeader - writes http status code
func (lrw *ResponseRecorder) WriteHeader(code int) {
if !lrw.headersLogged {
lrw.StatusCode = code
lrw.writeHeaders(&lrw.headers, code, lrw.ResponseWriter.Header())
lrw.headersLogged = true
lrw.ResponseWriter.WriteHeader(code)
}
}
// Flush - Calls the underlying Flush.
func (lrw *ResponseRecorder) Flush() {
lrw.ResponseWriter.(http.Flusher).Flush()
}
// Size - returns the number of bytes written
func (lrw *ResponseRecorder) Size() int {
return lrw.bytesWritten
}
// HeaderSize - returns the number of bytes of response headers written
func (lrw *ResponseRecorder) HeaderSize() int {
return lrw.headerBytesWritten
}