forked from TrueCloudLab/distribution
378 lines
10 KiB
Go
378 lines
10 KiB
Go
// Copyright 2013 The Gorilla Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package handlers
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import (
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"bufio"
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"fmt"
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"io"
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"net"
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"net/http"
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"net/url"
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"sort"
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"strconv"
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"strings"
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"time"
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"unicode/utf8"
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)
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// MethodHandler is an http.Handler that dispatches to a handler whose key in the MethodHandler's
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// map matches the name of the HTTP request's method, eg: GET
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//
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// If the request's method is OPTIONS and OPTIONS is not a key in the map then the handler
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// responds with a status of 200 and sets the Allow header to a comma-separated list of
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// available methods.
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//
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// If the request's method doesn't match any of its keys the handler responds with
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// a status of 405, Method not allowed and sets the Allow header to a comma-separated list
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// of available methods.
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type MethodHandler map[string]http.Handler
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func (h MethodHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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if handler, ok := h[req.Method]; ok {
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handler.ServeHTTP(w, req)
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} else {
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allow := []string{}
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for k := range h {
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allow = append(allow, k)
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}
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sort.Strings(allow)
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w.Header().Set("Allow", strings.Join(allow, ", "))
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if req.Method == "OPTIONS" {
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w.WriteHeader(http.StatusOK)
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} else {
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http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
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}
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}
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}
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// loggingHandler is the http.Handler implementation for LoggingHandlerTo and its friends
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type loggingHandler struct {
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writer io.Writer
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handler http.Handler
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}
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// combinedLoggingHandler is the http.Handler implementation for LoggingHandlerTo and its friends
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type combinedLoggingHandler struct {
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writer io.Writer
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handler http.Handler
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}
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func (h loggingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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t := time.Now()
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logger := makeLogger(w)
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url := *req.URL
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h.handler.ServeHTTP(logger, req)
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writeLog(h.writer, req, url, t, logger.Status(), logger.Size())
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}
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func (h combinedLoggingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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t := time.Now()
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logger := makeLogger(w)
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url := *req.URL
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h.handler.ServeHTTP(logger, req)
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writeCombinedLog(h.writer, req, url, t, logger.Status(), logger.Size())
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}
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func makeLogger(w http.ResponseWriter) loggingResponseWriter {
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var logger loggingResponseWriter = &responseLogger{w: w}
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if _, ok := w.(http.Hijacker); ok {
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logger = &hijackLogger{responseLogger{w: w}}
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}
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h, ok1 := logger.(http.Hijacker)
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c, ok2 := w.(http.CloseNotifier)
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if ok1 && ok2 {
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return hijackCloseNotifier{logger, h, c}
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}
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if ok2 {
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return &closeNotifyWriter{logger, c}
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}
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return logger
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}
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type loggingResponseWriter interface {
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http.ResponseWriter
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http.Flusher
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Status() int
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Size() int
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}
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// responseLogger is wrapper of http.ResponseWriter that keeps track of its HTTP status
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// code and body size
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type responseLogger struct {
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w http.ResponseWriter
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status int
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size int
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}
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func (l *responseLogger) Header() http.Header {
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return l.w.Header()
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}
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func (l *responseLogger) Write(b []byte) (int, error) {
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if l.status == 0 {
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// The status will be StatusOK if WriteHeader has not been called yet
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l.status = http.StatusOK
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}
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size, err := l.w.Write(b)
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l.size += size
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return size, err
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}
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func (l *responseLogger) WriteHeader(s int) {
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l.w.WriteHeader(s)
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l.status = s
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}
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func (l *responseLogger) Status() int {
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return l.status
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}
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func (l *responseLogger) Size() int {
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return l.size
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}
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func (l *responseLogger) Flush() {
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f, ok := l.w.(http.Flusher)
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if ok {
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f.Flush()
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}
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}
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type hijackLogger struct {
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responseLogger
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}
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func (l *hijackLogger) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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h := l.responseLogger.w.(http.Hijacker)
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conn, rw, err := h.Hijack()
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if err == nil && l.responseLogger.status == 0 {
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// The status will be StatusSwitchingProtocols if there was no error and WriteHeader has not been called yet
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l.responseLogger.status = http.StatusSwitchingProtocols
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}
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return conn, rw, err
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}
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type closeNotifyWriter struct {
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loggingResponseWriter
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http.CloseNotifier
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}
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type hijackCloseNotifier struct {
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loggingResponseWriter
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http.Hijacker
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http.CloseNotifier
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}
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const lowerhex = "0123456789abcdef"
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func appendQuoted(buf []byte, s string) []byte {
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var runeTmp [utf8.UTFMax]byte
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for width := 0; len(s) > 0; s = s[width:] {
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r := rune(s[0])
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width = 1
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if r >= utf8.RuneSelf {
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r, width = utf8.DecodeRuneInString(s)
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}
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if width == 1 && r == utf8.RuneError {
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buf = append(buf, `\x`...)
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buf = append(buf, lowerhex[s[0]>>4])
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buf = append(buf, lowerhex[s[0]&0xF])
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continue
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}
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if r == rune('"') || r == '\\' { // always backslashed
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buf = append(buf, '\\')
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buf = append(buf, byte(r))
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continue
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}
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if strconv.IsPrint(r) {
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n := utf8.EncodeRune(runeTmp[:], r)
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buf = append(buf, runeTmp[:n]...)
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continue
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}
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switch r {
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case '\a':
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buf = append(buf, `\a`...)
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case '\b':
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buf = append(buf, `\b`...)
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case '\f':
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buf = append(buf, `\f`...)
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case '\n':
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buf = append(buf, `\n`...)
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case '\r':
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buf = append(buf, `\r`...)
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case '\t':
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buf = append(buf, `\t`...)
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case '\v':
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buf = append(buf, `\v`...)
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default:
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switch {
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case r < ' ':
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buf = append(buf, `\x`...)
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buf = append(buf, lowerhex[s[0]>>4])
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buf = append(buf, lowerhex[s[0]&0xF])
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case r > utf8.MaxRune:
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r = 0xFFFD
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fallthrough
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case r < 0x10000:
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buf = append(buf, `\u`...)
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for s := 12; s >= 0; s -= 4 {
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buf = append(buf, lowerhex[r>>uint(s)&0xF])
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}
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default:
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buf = append(buf, `\U`...)
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for s := 28; s >= 0; s -= 4 {
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buf = append(buf, lowerhex[r>>uint(s)&0xF])
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}
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}
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}
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}
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return buf
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}
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// buildCommonLogLine builds a log entry for req in Apache Common Log Format.
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// ts is the timestamp with which the entry should be logged.
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// status and size are used to provide the response HTTP status and size.
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func buildCommonLogLine(req *http.Request, url url.URL, ts time.Time, status int, size int) []byte {
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username := "-"
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if url.User != nil {
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if name := url.User.Username(); name != "" {
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username = name
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}
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}
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host, _, err := net.SplitHostPort(req.RemoteAddr)
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if err != nil {
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host = req.RemoteAddr
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}
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uri := url.RequestURI()
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buf := make([]byte, 0, 3*(len(host)+len(username)+len(req.Method)+len(uri)+len(req.Proto)+50)/2)
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buf = append(buf, host...)
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buf = append(buf, " - "...)
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buf = append(buf, username...)
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buf = append(buf, " ["...)
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buf = append(buf, ts.Format("02/Jan/2006:15:04:05 -0700")...)
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buf = append(buf, `] "`...)
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buf = append(buf, req.Method...)
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buf = append(buf, " "...)
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buf = appendQuoted(buf, uri)
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buf = append(buf, " "...)
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buf = append(buf, req.Proto...)
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buf = append(buf, `" `...)
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buf = append(buf, strconv.Itoa(status)...)
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buf = append(buf, " "...)
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buf = append(buf, strconv.Itoa(size)...)
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return buf
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}
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// writeLog writes a log entry for req to w in Apache Common Log Format.
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// ts is the timestamp with which the entry should be logged.
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// status and size are used to provide the response HTTP status and size.
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func writeLog(w io.Writer, req *http.Request, url url.URL, ts time.Time, status, size int) {
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buf := buildCommonLogLine(req, url, ts, status, size)
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buf = append(buf, '\n')
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w.Write(buf)
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}
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// writeCombinedLog writes a log entry for req to w in Apache Combined Log Format.
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// ts is the timestamp with which the entry should be logged.
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// status and size are used to provide the response HTTP status and size.
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func writeCombinedLog(w io.Writer, req *http.Request, url url.URL, ts time.Time, status, size int) {
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buf := buildCommonLogLine(req, url, ts, status, size)
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buf = append(buf, ` "`...)
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buf = appendQuoted(buf, req.Referer())
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buf = append(buf, `" "`...)
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buf = appendQuoted(buf, req.UserAgent())
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buf = append(buf, '"', '\n')
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w.Write(buf)
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}
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// CombinedLoggingHandler return a http.Handler that wraps h and logs requests to out in
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// Apache Combined Log Format.
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//
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// See http://httpd.apache.org/docs/2.2/logs.html#combined for a description of this format.
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//
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// LoggingHandler always sets the ident field of the log to -
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func CombinedLoggingHandler(out io.Writer, h http.Handler) http.Handler {
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return combinedLoggingHandler{out, h}
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}
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// LoggingHandler return a http.Handler that wraps h and logs requests to out in
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// Apache Common Log Format (CLF).
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//
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// See http://httpd.apache.org/docs/2.2/logs.html#common for a description of this format.
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//
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// LoggingHandler always sets the ident field of the log to -
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func LoggingHandler(out io.Writer, h http.Handler) http.Handler {
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return loggingHandler{out, h}
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}
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// isContentType validates the Content-Type header
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// is contentType. That is, its type and subtype match.
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func isContentType(h http.Header, contentType string) bool {
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ct := h.Get("Content-Type")
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if i := strings.IndexRune(ct, ';'); i != -1 {
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ct = ct[0:i]
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}
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return ct == contentType
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}
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// ContentTypeHandler wraps and returns a http.Handler, validating the request content type
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// is acompatible with the contentTypes list.
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// It writes a HTTP 415 error if that fails.
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//
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// Only PUT, POST, and PATCH requests are considered.
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func ContentTypeHandler(h http.Handler, contentTypes ...string) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if !(r.Method == "PUT" || r.Method == "POST" || r.Method == "PATCH") {
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h.ServeHTTP(w, r)
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return
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}
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for _, ct := range contentTypes {
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if isContentType(r.Header, ct) {
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h.ServeHTTP(w, r)
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return
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}
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}
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http.Error(w, fmt.Sprintf("Unsupported content type %q; expected one of %q", r.Header.Get("Content-Type"), contentTypes), http.StatusUnsupportedMediaType)
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})
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}
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const (
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// HTTPMethodOverrideHeader is a commonly used
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// http header to override a request method.
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HTTPMethodOverrideHeader = "X-HTTP-Method-Override"
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// HTTPMethodOverrideFormKey is a commonly used
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// HTML form key to override a request method.
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HTTPMethodOverrideFormKey = "_method"
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)
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// HTTPMethodOverrideHandler wraps and returns a http.Handler which checks for the X-HTTP-Method-Override header
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// or the _method form key, and overrides (if valid) request.Method with its value.
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//
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// This is especially useful for http clients that don't support many http verbs.
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// It isn't secure to override e.g a GET to a POST, so only POST requests are considered.
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// Likewise, the override method can only be a "write" method: PUT, PATCH or DELETE.
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//
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// Form method takes precedence over header method.
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func HTTPMethodOverrideHandler(h http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if r.Method == "POST" {
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om := r.FormValue(HTTPMethodOverrideFormKey)
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if om == "" {
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om = r.Header.Get(HTTPMethodOverrideHeader)
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}
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if om == "PUT" || om == "PATCH" || om == "DELETE" {
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r.Method = om
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}
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}
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h.ServeHTTP(w, r)
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})
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}
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