distribution/vendor/github.com/gorilla/handlers/handlers.go

379 lines
10 KiB
Go
Raw Normal View History

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