// 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 . package http import ( "bytes" "errors" "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 io.ReaderFrom 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 { rf, _ := w.(io.ReaderFrom) return &ResponseRecorder{ ResponseWriter: w, ReaderFrom: rf, StatusCode: http.StatusOK, StartTime: time.Now().UTC(), } } // ErrNotImplemented when a functionality is not implemented var ErrNotImplemented = errors.New("not implemented") // ReadFrom implements support for calling internal io.ReaderFrom implementations // returns an error if the underlying ResponseWriter does not implement io.ReaderFrom func (lrw *ResponseRecorder) ReadFrom(r io.Reader) (int64, error) { if lrw.ReaderFrom != nil { return lrw.ReaderFrom.ReadFrom(r) } return 0, ErrNotImplemented } 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) } gzipped := lrw.Header().Get("Content-Encoding") == "gzip" if !gzipped && ((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 } } // blobBody returns a dummy body placeholder for blob (binary stream) var blobBody = []byte("") // gzippedBody returns a dummy body placeholder for gzipped content var gzippedBody = []byte("") // Body - Return response body. func (lrw *ResponseRecorder) Body() []byte { if lrw.Header().Get("Content-Encoding") == "gzip" { // ... otherwise we return the place holder return gzippedBody } // 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 place holder return blobBody } // 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 }