Bump Gorilla Handlers to v1.5.1.

Signed-off-by: olegburov <oleg.burov@outlook.com>
2020-08-31 20:48:55 -07:00 · 2020-08-31 20:48:55 -07:00 · 03aaf6ab51
commit 03aaf6ab51
parent f4506b517a
24 changed files with 1732 additions and 338 deletions
--- a/vendor/github.com/gorilla/handlers/.travis.yml
+++ b/vendor/github.com/gorilla/handlers/.travis.yml
@ -1,8 +0,0 @@
-language: go
-
-go:
-  - 1.1
-  - 1.2
-  - 1.3
-  - 1.4
-  - tip
--- a/vendor/github.com/gorilla/handlers/README.md
+++ b/vendor/github.com/gorilla/handlers/README.md
@ -1,28 +1,32 @@
 gorilla/handlers
 ================
-[![GoDoc](https://godoc.org/github.com/gorilla/handlers?status.svg)](https://godoc.org/github.com/gorilla/handlers) [![Build Status](https://travis-ci.org/gorilla/handlers.svg?branch=master)](https://travis-ci.org/gorilla/handlers)
+[![GoDoc](https://godoc.org/github.com/gorilla/handlers?status.svg)](https://godoc.org/github.com/gorilla/handlers)
+[![CircleCI](https://circleci.com/gh/gorilla/handlers.svg?style=svg)](https://circleci.com/gh/gorilla/handlers)
+[![Sourcegraph](https://sourcegraph.com/github.com/gorilla/handlers/-/badge.svg)](https://sourcegraph.com/github.com/gorilla/handlers?badge)
+

 Package handlers is a collection of handlers (aka "HTTP middleware") for use
 with Go's `net/http` package (or any framework supporting `http.Handler`), including:

-* `LoggingHandler` for logging HTTP requests in the Apache [Common Log
+* [**LoggingHandler**](https://godoc.org/github.com/gorilla/handlers#LoggingHandler) for logging HTTP requests in the Apache [Common Log
  Format](http://httpd.apache.org/docs/2.2/logs.html#common).
-* `CombinedLoggingHandler` for logging HTTP requests in the Apache [Combined Log
+* [**CombinedLoggingHandler**](https://godoc.org/github.com/gorilla/handlers#CombinedLoggingHandler) for logging HTTP requests in the Apache [Combined Log
  Format](http://httpd.apache.org/docs/2.2/logs.html#combined) commonly used by
  both Apache and nginx.
-* `CompressHandler` for gzipping responses.
-* `ContentTypeHandler` for validating requests against a list of accepted
+* [**CompressHandler**](https://godoc.org/github.com/gorilla/handlers#CompressHandler) for gzipping responses.
+* [**ContentTypeHandler**](https://godoc.org/github.com/gorilla/handlers#ContentTypeHandler) for validating requests against a list of accepted
  content types.
-* `MethodHandler` for matching HTTP methods against handlers in a
+* [**MethodHandler**](https://godoc.org/github.com/gorilla/handlers#MethodHandler) for matching HTTP methods against handlers in a
  `map[string]http.Handler`
-* `ProxyHeaders` for populating `r.RemoteAddr` and `r.URL.Scheme` based on the
+* [**ProxyHeaders**](https://godoc.org/github.com/gorilla/handlers#ProxyHeaders) for populating `r.RemoteAddr` and `r.URL.Scheme` based on the
  `X-Forwarded-For`, `X-Real-IP`, `X-Forwarded-Proto` and RFC7239 `Forwarded`
  headers when running a Go server behind a HTTP reverse proxy.
-* `CanonicalHost` for re-directing to the preferred host when handling multiple 
+* [**CanonicalHost**](https://godoc.org/github.com/gorilla/handlers#CanonicalHost) for re-directing to the preferred host when handling multiple 
  domains (i.e. multiple CNAME aliases).
+* [**RecoveryHandler**](https://godoc.org/github.com/gorilla/handlers#RecoveryHandler) for recovering from unexpected panics.

 Other handlers are documented [on the Gorilla
-website](http://www.gorillatoolkit.org/pkg/handlers).
+website](https://www.gorillatoolkit.org/pkg/handlers).

 ## Example

--- a/vendor/github.com/gorilla/handlers/canonical.go
+++ b/vendor/github.com/gorilla/handlers/canonical.go
@ -18,7 +18,6 @@ type canonical struct {
 //
 // Note: If the provided domain is considered invalid by url.Parse or otherwise
 // returns an empty scheme or host, clients are not re-directed.
-// not re-directed.
 //
 // Example:
 //
@ -54,7 +53,11 @@ func (c canonical) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	if !strings.EqualFold(cleanHost(r.Host), dest.Host) {
 		// Re-build the destination URL
 		dest := dest.Scheme + "://" + dest.Host + r.URL.Path
+		if r.URL.RawQuery != "" {
+			dest += "?" + r.URL.RawQuery
+		}
 		http.Redirect(w, r, dest, c.code)
+		return
 	}

 	c.h.ServeHTTP(w, r)
--- a/vendor/github.com/gorilla/handlers/compress.go
+++ b/vendor/github.com/gorilla/handlers/compress.go
@ -10,75 +10,134 @@ import (
 	"io"
 	"net/http"
 	"strings"
+
+	"github.com/felixge/httpsnoop"
 )

+const acceptEncoding string = "Accept-Encoding"
+
 type compressResponseWriter struct {
-	io.Writer
-	http.ResponseWriter
-	http.Hijacker
+	compressor io.Writer
+	w          http.ResponseWriter
 }

-func (w *compressResponseWriter) Header() http.Header {
-	return w.ResponseWriter.Header()
+func (cw *compressResponseWriter) WriteHeader(c int) {
+	cw.w.Header().Del("Content-Length")
+	cw.w.WriteHeader(c)
 }

-func (w *compressResponseWriter) Write(b []byte) (int, error) {
-	h := w.ResponseWriter.Header()
+func (cw *compressResponseWriter) Write(b []byte) (int, error) {
+	h := cw.w.Header()
 	if h.Get("Content-Type") == "" {
 		h.Set("Content-Type", http.DetectContentType(b))
 	}
+	h.Del("Content-Length")

-	return w.Writer.Write(b)
+	return cw.compressor.Write(b)
+}
+
+func (cw *compressResponseWriter) ReadFrom(r io.Reader) (int64, error) {
+	return io.Copy(cw.compressor, r)
+}
+
+type flusher interface {
+	Flush() error
+}
+
+func (w *compressResponseWriter) Flush() {
+	// Flush compressed data if compressor supports it.
+	if f, ok := w.compressor.(flusher); ok {
+		f.Flush()
+	}
+	// Flush HTTP response.
+	if f, ok := w.w.(http.Flusher); ok {
+		f.Flush()
+	}
 }

 // CompressHandler gzip compresses HTTP responses for clients that support it
 // via the 'Accept-Encoding' header.
+//
+// Compressing TLS traffic may leak the page contents to an attacker if the
+// page contains user input: http://security.stackexchange.com/a/102015/12208
 func CompressHandler(h http.Handler) http.Handler {
+	return CompressHandlerLevel(h, gzip.DefaultCompression)
+}
+
+// CompressHandlerLevel gzip compresses HTTP responses with specified compression level
+// for clients that support it via the 'Accept-Encoding' header.
+//
+// The compression level should be gzip.DefaultCompression, gzip.NoCompression,
+// or any integer value between gzip.BestSpeed and gzip.BestCompression inclusive.
+// gzip.DefaultCompression is used in case of invalid compression level.
+func CompressHandlerLevel(h http.Handler, level int) http.Handler {
+	if level < gzip.DefaultCompression || level > gzip.BestCompression {
+		level = gzip.DefaultCompression
+	}
+
+	const (
+		gzipEncoding  = "gzip"
+		flateEncoding = "deflate"
+	)
+
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-	L:
-		for _, enc := range strings.Split(r.Header.Get("Accept-Encoding"), ",") {
-			switch strings.TrimSpace(enc) {
-			case "gzip":
-				w.Header().Set("Content-Encoding", "gzip")
-				w.Header().Add("Vary", "Accept-Encoding")
-
-				gw := gzip.NewWriter(w)
-				defer gw.Close()
-
-				h, hok := w.(http.Hijacker)
-				if !hok { /* w is not Hijacker... oh well... */
-					h = nil
-				}
-
-				w = &compressResponseWriter{
-					Writer:         gw,
-					ResponseWriter: w,
-					Hijacker:       h,
-				}
-
-				break L
-			case "deflate":
-				w.Header().Set("Content-Encoding", "deflate")
-				w.Header().Add("Vary", "Accept-Encoding")
-
-				fw, _ := flate.NewWriter(w, flate.DefaultCompression)
-				defer fw.Close()
-
-				h, hok := w.(http.Hijacker)
-				if !hok { /* w is not Hijacker... oh well... */
-					h = nil
-				}
-
-				w = &compressResponseWriter{
-					Writer:         fw,
-					ResponseWriter: w,
-					Hijacker:       h,
-				}
-
-				break L
+		// detect what encoding to use
+		var encoding string
+		for _, curEnc := range strings.Split(r.Header.Get(acceptEncoding), ",") {
+			curEnc = strings.TrimSpace(curEnc)
+			if curEnc == gzipEncoding || curEnc == flateEncoding {
+				encoding = curEnc
+				break
 			}
 		}

+		// always add Accept-Encoding to Vary to prevent intermediate caches corruption
+		w.Header().Add("Vary", acceptEncoding)
+
+		// if we weren't able to identify an encoding we're familiar with, pass on the
+		// request to the handler and return
+		if encoding == "" {
+			h.ServeHTTP(w, r)
+			return
+		}
+
+		if r.Header.Get("Upgrade") != "" {
+			h.ServeHTTP(w, r)
+			return
+		}
+
+		// wrap the ResponseWriter with the writer for the chosen encoding
+		var encWriter io.WriteCloser
+		if encoding == gzipEncoding {
+			encWriter, _ = gzip.NewWriterLevel(w, level)
+		} else if encoding == flateEncoding {
+			encWriter, _ = flate.NewWriter(w, level)
+		}
+		defer encWriter.Close()
+
+		w.Header().Set("Content-Encoding", encoding)
+		r.Header.Del(acceptEncoding)
+
+		cw := &compressResponseWriter{
+			w:          w,
+			compressor: encWriter,
+		}
+
+		w = httpsnoop.Wrap(w, httpsnoop.Hooks{
+			Write: func(httpsnoop.WriteFunc) httpsnoop.WriteFunc {
+				return cw.Write
+			},
+			WriteHeader: func(httpsnoop.WriteHeaderFunc) httpsnoop.WriteHeaderFunc {
+				return cw.WriteHeader
+			},
+			Flush: func(httpsnoop.FlushFunc) httpsnoop.FlushFunc {
+				return cw.Flush
+			},
+			ReadFrom: func(rff httpsnoop.ReadFromFunc) httpsnoop.ReadFromFunc {
+				return cw.ReadFrom
+			},
+		})
+
 		h.ServeHTTP(w, r)
 	})
 }
--- a/vendor/github.com/gorilla/handlers/cors.go
+++ b/vendor/github.com/gorilla/handlers/cors.go
@ -0,0 +1,355 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+)
+
+// CORSOption represents a functional option for configuring the CORS middleware.
+type CORSOption func(*cors) error
+
+type cors struct {
+	h                      http.Handler
+	allowedHeaders         []string
+	allowedMethods         []string
+	allowedOrigins         []string
+	allowedOriginValidator OriginValidator
+	exposedHeaders         []string
+	maxAge                 int
+	ignoreOptions          bool
+	allowCredentials       bool
+	optionStatusCode       int
+}
+
+// OriginValidator takes an origin string and returns whether or not that origin is allowed.
+type OriginValidator func(string) bool
+
+var (
+	defaultCorsOptionStatusCode = 200
+	defaultCorsMethods          = []string{"GET", "HEAD", "POST"}
+	defaultCorsHeaders          = []string{"Accept", "Accept-Language", "Content-Language", "Origin"}
+	// (WebKit/Safari v9 sends the Origin header by default in AJAX requests)
+)
+
+const (
+	corsOptionMethod           string = "OPTIONS"
+	corsAllowOriginHeader      string = "Access-Control-Allow-Origin"
+	corsExposeHeadersHeader    string = "Access-Control-Expose-Headers"
+	corsMaxAgeHeader           string = "Access-Control-Max-Age"
+	corsAllowMethodsHeader     string = "Access-Control-Allow-Methods"
+	corsAllowHeadersHeader     string = "Access-Control-Allow-Headers"
+	corsAllowCredentialsHeader string = "Access-Control-Allow-Credentials"
+	corsRequestMethodHeader    string = "Access-Control-Request-Method"
+	corsRequestHeadersHeader   string = "Access-Control-Request-Headers"
+	corsOriginHeader           string = "Origin"
+	corsVaryHeader             string = "Vary"
+	corsOriginMatchAll         string = "*"
+)
+
+func (ch *cors) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	origin := r.Header.Get(corsOriginHeader)
+	if !ch.isOriginAllowed(origin) {
+		if r.Method != corsOptionMethod || ch.ignoreOptions {
+			ch.h.ServeHTTP(w, r)
+		}
+
+		return
+	}
+
+	if r.Method == corsOptionMethod {
+		if ch.ignoreOptions {
+			ch.h.ServeHTTP(w, r)
+			return
+		}
+
+		if _, ok := r.Header[corsRequestMethodHeader]; !ok {
+			w.WriteHeader(http.StatusBadRequest)
+			return
+		}
+
+		method := r.Header.Get(corsRequestMethodHeader)
+		if !ch.isMatch(method, ch.allowedMethods) {
+			w.WriteHeader(http.StatusMethodNotAllowed)
+			return
+		}
+
+		requestHeaders := strings.Split(r.Header.Get(corsRequestHeadersHeader), ",")
+		allowedHeaders := []string{}
+		for _, v := range requestHeaders {
+			canonicalHeader := http.CanonicalHeaderKey(strings.TrimSpace(v))
+			if canonicalHeader == "" || ch.isMatch(canonicalHeader, defaultCorsHeaders) {
+				continue
+			}
+
+			if !ch.isMatch(canonicalHeader, ch.allowedHeaders) {
+				w.WriteHeader(http.StatusForbidden)
+				return
+			}
+
+			allowedHeaders = append(allowedHeaders, canonicalHeader)
+		}
+
+		if len(allowedHeaders) > 0 {
+			w.Header().Set(corsAllowHeadersHeader, strings.Join(allowedHeaders, ","))
+		}
+
+		if ch.maxAge > 0 {
+			w.Header().Set(corsMaxAgeHeader, strconv.Itoa(ch.maxAge))
+		}
+
+		if !ch.isMatch(method, defaultCorsMethods) {
+			w.Header().Set(corsAllowMethodsHeader, method)
+		}
+	} else {
+		if len(ch.exposedHeaders) > 0 {
+			w.Header().Set(corsExposeHeadersHeader, strings.Join(ch.exposedHeaders, ","))
+		}
+	}
+
+	if ch.allowCredentials {
+		w.Header().Set(corsAllowCredentialsHeader, "true")
+	}
+
+	if len(ch.allowedOrigins) > 1 {
+		w.Header().Set(corsVaryHeader, corsOriginHeader)
+	}
+
+	returnOrigin := origin
+	if ch.allowedOriginValidator == nil && len(ch.allowedOrigins) == 0 {
+		returnOrigin = "*"
+	} else {
+		for _, o := range ch.allowedOrigins {
+			// A configuration of * is different than explicitly setting an allowed
+			// origin. Returning arbitrary origin headers in an access control allow
+			// origin header is unsafe and is not required by any use case.
+			if o == corsOriginMatchAll {
+				returnOrigin = "*"
+				break
+			}
+		}
+	}
+	w.Header().Set(corsAllowOriginHeader, returnOrigin)
+
+	if r.Method == corsOptionMethod {
+		w.WriteHeader(ch.optionStatusCode)
+		return
+	}
+	ch.h.ServeHTTP(w, r)
+}
+
+// CORS provides Cross-Origin Resource Sharing middleware.
+// Example:
+//
+//  import (
+//      "net/http"
+//
+//      "github.com/gorilla/handlers"
+//      "github.com/gorilla/mux"
+//  )
+//
+//  func main() {
+//      r := mux.NewRouter()
+//      r.HandleFunc("/users", UserEndpoint)
+//      r.HandleFunc("/projects", ProjectEndpoint)
+//
+//      // Apply the CORS middleware to our top-level router, with the defaults.
+//      http.ListenAndServe(":8000", handlers.CORS()(r))
+//  }
+//
+func CORS(opts ...CORSOption) func(http.Handler) http.Handler {
+	return func(h http.Handler) http.Handler {
+		ch := parseCORSOptions(opts...)
+		ch.h = h
+		return ch
+	}
+}
+
+func parseCORSOptions(opts ...CORSOption) *cors {
+	ch := &cors{
+		allowedMethods:   defaultCorsMethods,
+		allowedHeaders:   defaultCorsHeaders,
+		allowedOrigins:   []string{},
+		optionStatusCode: defaultCorsOptionStatusCode,
+	}
+
+	for _, option := range opts {
+		option(ch)
+	}
+
+	return ch
+}
+
+//
+// Functional options for configuring CORS.
+//
+
+// AllowedHeaders adds the provided headers to the list of allowed headers in a
+// CORS request.
+// This is an append operation so the headers Accept, Accept-Language,
+// and Content-Language are always allowed.
+// Content-Type must be explicitly declared if accepting Content-Types other than
+// application/x-www-form-urlencoded, multipart/form-data, or text/plain.
+func AllowedHeaders(headers []string) CORSOption {
+	return func(ch *cors) error {
+		for _, v := range headers {
+			normalizedHeader := http.CanonicalHeaderKey(strings.TrimSpace(v))
+			if normalizedHeader == "" {
+				continue
+			}
+
+			if !ch.isMatch(normalizedHeader, ch.allowedHeaders) {
+				ch.allowedHeaders = append(ch.allowedHeaders, normalizedHeader)
+			}
+		}
+
+		return nil
+	}
+}
+
+// AllowedMethods can be used to explicitly allow methods in the
+// Access-Control-Allow-Methods header.
+// This is a replacement operation so you must also
+// pass GET, HEAD, and POST if you wish to support those methods.
+func AllowedMethods(methods []string) CORSOption {
+	return func(ch *cors) error {
+		ch.allowedMethods = []string{}
+		for _, v := range methods {
+			normalizedMethod := strings.ToUpper(strings.TrimSpace(v))
+			if normalizedMethod == "" {
+				continue
+			}
+
+			if !ch.isMatch(normalizedMethod, ch.allowedMethods) {
+				ch.allowedMethods = append(ch.allowedMethods, normalizedMethod)
+			}
+		}
+
+		return nil
+	}
+}
+
+// AllowedOrigins sets the allowed origins for CORS requests, as used in the
+// 'Allow-Access-Control-Origin' HTTP header.
+// Note: Passing in a []string{"*"} will allow any domain.
+func AllowedOrigins(origins []string) CORSOption {
+	return func(ch *cors) error {
+		for _, v := range origins {
+			if v == corsOriginMatchAll {
+				ch.allowedOrigins = []string{corsOriginMatchAll}
+				return nil
+			}
+		}
+
+		ch.allowedOrigins = origins
+		return nil
+	}
+}
+
+// AllowedOriginValidator sets a function for evaluating allowed origins in CORS requests, represented by the
+// 'Allow-Access-Control-Origin' HTTP header.
+func AllowedOriginValidator(fn OriginValidator) CORSOption {
+	return func(ch *cors) error {
+		ch.allowedOriginValidator = fn
+		return nil
+	}
+}
+
+// OptionStatusCode sets a custom status code on the OPTIONS requests.
+// Default behaviour sets it to 200 to reflect best practices. This is option is not mandatory
+// and can be used if you need a custom status code (i.e 204).
+//
+// More informations on the spec:
+// https://fetch.spec.whatwg.org/#cors-preflight-fetch
+func OptionStatusCode(code int) CORSOption {
+	return func(ch *cors) error {
+		ch.optionStatusCode = code
+		return nil
+	}
+}
+
+// ExposedHeaders can be used to specify headers that are available
+// and will not be stripped out by the user-agent.
+func ExposedHeaders(headers []string) CORSOption {
+	return func(ch *cors) error {
+		ch.exposedHeaders = []string{}
+		for _, v := range headers {
+			normalizedHeader := http.CanonicalHeaderKey(strings.TrimSpace(v))
+			if normalizedHeader == "" {
+				continue
+			}
+
+			if !ch.isMatch(normalizedHeader, ch.exposedHeaders) {
+				ch.exposedHeaders = append(ch.exposedHeaders, normalizedHeader)
+			}
+		}
+
+		return nil
+	}
+}
+
+// MaxAge determines the maximum age (in seconds) between preflight requests. A
+// maximum of 10 minutes is allowed. An age above this value will default to 10
+// minutes.
+func MaxAge(age int) CORSOption {
+	return func(ch *cors) error {
+		// Maximum of 10 minutes.
+		if age > 600 {
+			age = 600
+		}
+
+		ch.maxAge = age
+		return nil
+	}
+}
+
+// IgnoreOptions causes the CORS middleware to ignore OPTIONS requests, instead
+// passing them through to the next handler. This is useful when your application
+// or framework has a pre-existing mechanism for responding to OPTIONS requests.
+func IgnoreOptions() CORSOption {
+	return func(ch *cors) error {
+		ch.ignoreOptions = true
+		return nil
+	}
+}
+
+// AllowCredentials can be used to specify that the user agent may pass
+// authentication details along with the request.
+func AllowCredentials() CORSOption {
+	return func(ch *cors) error {
+		ch.allowCredentials = true
+		return nil
+	}
+}
+
+func (ch *cors) isOriginAllowed(origin string) bool {
+	if origin == "" {
+		return false
+	}
+
+	if ch.allowedOriginValidator != nil {
+		return ch.allowedOriginValidator(origin)
+	}
+
+	if len(ch.allowedOrigins) == 0 {
+		return true
+	}
+
+	for _, allowedOrigin := range ch.allowedOrigins {
+		if allowedOrigin == origin || allowedOrigin == corsOriginMatchAll {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (ch *cors) isMatch(needle string, haystack []string) bool {
+	for _, v := range haystack {
+		if v == needle {
+			return true
+		}
+	}
+
+	return false
+}
--- a/vendor/github.com/gorilla/handlers/go.mod
+++ b/vendor/github.com/gorilla/handlers/go.mod
@ -0,0 +1,5 @@
+module github.com/gorilla/handlers
+
+go 1.14
+
+require github.com/felixge/httpsnoop v1.0.1
--- a/vendor/github.com/gorilla/handlers/go.sum
+++ b/vendor/github.com/gorilla/handlers/go.sum
@ -0,0 +1,2 @@
+github.com/felixge/httpsnoop v1.0.1 h1:lvB5Jl89CsZtGIWuTcDM1E/vkVs49/Ml7JJe07l8SPQ=
+github.com/felixge/httpsnoop v1.0.1/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
--- a/vendor/github.com/gorilla/handlers/handlers.go
+++ b/vendor/github.com/gorilla/handlers/handlers.go
@ -7,27 +7,22 @@ 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
+// 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 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.
+// If the request's method doesn't match any of its keys the handler responds
+// with a status of HTTP 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) {
@ -48,74 +43,15 @@ func (h MethodHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 }

-// 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
+// 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
@ -134,187 +70,18 @@ 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
+func (l *responseLogger) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	conn, rw, err := l.w.(http.Hijacker).Hijack()
+	if err == nil && l.status == 0 {
+		// The status will be StatusSwitchingProtocols if there was no error and
+		// WriteHeader has not been called yet
+		l.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.
+// isContentType validates the Content-Type header matches the supplied
+// 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 {
@ -323,9 +90,9 @@ func isContentType(h http.Header, contentType string) bool {
 	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.
+// ContentTypeHandler wraps and returns a http.Handler, validating the request
+// content type is compatible 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 {
@ -354,12 +121,14 @@ const (
 	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.
+// 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.
+// 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 {
--- a/vendor/github.com/gorilla/handlers/logging.go
+++ b/vendor/github.com/gorilla/handlers/logging.go
@ -0,0 +1,244 @@
+// 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 (
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"strconv"
+	"time"
+	"unicode/utf8"
+
+	"github.com/felixge/httpsnoop"
+)
+
+// Logging
+
+// LogFormatterParams is the structure any formatter will be handed when time to log comes
+type LogFormatterParams struct {
+	Request    *http.Request
+	URL        url.URL
+	TimeStamp  time.Time
+	StatusCode int
+	Size       int
+}
+
+// LogFormatter gives the signature of the formatter function passed to CustomLoggingHandler
+type LogFormatter func(writer io.Writer, params LogFormatterParams)
+
+// loggingHandler is the http.Handler implementation for LoggingHandlerTo and its
+// friends
+
+type loggingHandler struct {
+	writer    io.Writer
+	handler   http.Handler
+	formatter LogFormatter
+}
+
+func (h loggingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	t := time.Now()
+	logger, w := makeLogger(w)
+	url := *req.URL
+
+	h.handler.ServeHTTP(w, req)
+	if req.MultipartForm != nil {
+		req.MultipartForm.RemoveAll()
+	}
+
+	params := LogFormatterParams{
+		Request:    req,
+		URL:        url,
+		TimeStamp:  t,
+		StatusCode: logger.Status(),
+		Size:       logger.Size(),
+	}
+
+	h.formatter(h.writer, params)
+}
+
+func makeLogger(w http.ResponseWriter) (*responseLogger, http.ResponseWriter) {
+	logger := &responseLogger{w: w, status: http.StatusOK}
+	return logger, httpsnoop.Wrap(w, httpsnoop.Hooks{
+		Write: func(httpsnoop.WriteFunc) httpsnoop.WriteFunc {
+			return logger.Write
+		},
+		WriteHeader: func(httpsnoop.WriteHeaderFunc) httpsnoop.WriteHeaderFunc {
+			return logger.WriteHeader
+		},
+	})
+}
+
+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 := req.RequestURI
+
+	// Requests using the CONNECT method over HTTP/2.0 must use
+	// the authority field (aka r.Host) to identify the target.
+	// Refer: https://httpwg.github.io/specs/rfc7540.html#CONNECT
+	if req.ProtoMajor == 2 && req.Method == "CONNECT" {
+		uri = req.Host
+	}
+	if uri == "" {
+		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(writer io.Writer, params LogFormatterParams) {
+	buf := buildCommonLogLine(params.Request, params.URL, params.TimeStamp, params.StatusCode, params.Size)
+	buf = append(buf, '\n')
+	writer.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(writer io.Writer, params LogFormatterParams) {
+	buf := buildCommonLogLine(params.Request, params.URL, params.TimeStamp, params.StatusCode, params.Size)
+	buf = append(buf, ` "`...)
+	buf = appendQuoted(buf, params.Request.Referer())
+	buf = append(buf, `" "`...)
+	buf = appendQuoted(buf, params.Request.UserAgent())
+	buf = append(buf, '"', '\n')
+	writer.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 loggingHandler{out, h, writeCombinedLog}
+}
+
+// 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 -
+//
+// Example:
+//
+//  r := mux.NewRouter()
+//  r.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+//  	w.Write([]byte("This is a catch-all route"))
+//  })
+//  loggedRouter := handlers.LoggingHandler(os.Stdout, r)
+//  http.ListenAndServe(":1123", loggedRouter)
+//
+func LoggingHandler(out io.Writer, h http.Handler) http.Handler {
+	return loggingHandler{out, h, writeLog}
+}
+
+// CustomLoggingHandler provides a way to supply a custom log formatter
+// while taking advantage of the mechanisms in this package
+func CustomLoggingHandler(out io.Writer, h http.Handler, f LogFormatter) http.Handler {
+	return loggingHandler{out, h, f}
+}
--- a/vendor/github.com/gorilla/handlers/proxy_headers.go
+++ b/vendor/github.com/gorilla/handlers/proxy_headers.go
@ -8,9 +8,11 @@ import (

 var (
 	// De-facto standard header keys.
-	xForwardedFor   = http.CanonicalHeaderKey("X-Forwarded-For")
-	xRealIP         = http.CanonicalHeaderKey("X-Real-IP")
-	xForwardedProto = http.CanonicalHeaderKey("X-Forwarded-Scheme")
+	xForwardedFor    = http.CanonicalHeaderKey("X-Forwarded-For")
+	xForwardedHost   = http.CanonicalHeaderKey("X-Forwarded-Host")
+	xForwardedProto  = http.CanonicalHeaderKey("X-Forwarded-Proto")
+	xForwardedScheme = http.CanonicalHeaderKey("X-Forwarded-Scheme")
+	xRealIP          = http.CanonicalHeaderKey("X-Real-IP")
 )

 var (
@ -28,9 +30,9 @@ var (

 // ProxyHeaders inspects common reverse proxy headers and sets the corresponding
 // fields in the HTTP request struct. These are X-Forwarded-For and X-Real-IP
-// for the remote (client) IP address, X-Forwarded-Proto for the scheme
-// (http|https) and the RFC7239 Forwarded header, which may include both client
-// IPs and schemes.
+// for the remote (client) IP address, X-Forwarded-Proto or X-Forwarded-Scheme
+// for the scheme (http|https), X-Forwarded-Host for the host and the RFC7239
+// Forwarded header, which may include both client IPs and schemes.
 //
 // NOTE: This middleware should only be used when behind a reverse
 // proxy like nginx, HAProxy or Apache. Reverse proxies that don't (or are
@ -49,7 +51,10 @@ func ProxyHeaders(h http.Handler) http.Handler {
 		if scheme := getScheme(r); scheme != "" {
 			r.URL.Scheme = scheme
 		}
-
+		// Set the host with the value passed by the proxy
+		if r.Header.Get(xForwardedHost) != "" {
+			r.Host = r.Header.Get(xForwardedHost)
+		}
 		// Call the next handler in the chain.
 		h.ServeHTTP(w, r)
 	}
@ -99,7 +104,9 @@ func getScheme(r *http.Request) string {
 	// Retrieve the scheme from X-Forwarded-Proto.
 	if proto := r.Header.Get(xForwardedProto); proto != "" {
 		scheme = strings.ToLower(proto)
-	} else if proto := r.Header.Get(forwarded); proto != "" {
+	} else if proto = r.Header.Get(xForwardedScheme); proto != "" {
+		scheme = strings.ToLower(proto)
+	} else if proto = r.Header.Get(forwarded); proto != "" {
 		// match should contain at least two elements if the protocol was
 		// specified in the Forwarded header. The first element will always be
 		// the 'proto=' capture, which we ignore. In the case of multiple proto
--- a/vendor/github.com/gorilla/handlers/recovery.go
+++ b/vendor/github.com/gorilla/handlers/recovery.go
@ -0,0 +1,96 @@
+package handlers
+
+import (
+	"log"
+	"net/http"
+	"runtime/debug"
+)
+
+// RecoveryHandlerLogger is an interface used by the recovering handler to print logs.
+type RecoveryHandlerLogger interface {
+	Println(...interface{})
+}
+
+type recoveryHandler struct {
+	handler    http.Handler
+	logger     RecoveryHandlerLogger
+	printStack bool
+}
+
+// RecoveryOption provides a functional approach to define
+// configuration for a handler; such as setting the logging
+// whether or not to print stack traces on panic.
+type RecoveryOption func(http.Handler)
+
+func parseRecoveryOptions(h http.Handler, opts ...RecoveryOption) http.Handler {
+	for _, option := range opts {
+		option(h)
+	}
+
+	return h
+}
+
+// RecoveryHandler is HTTP middleware that recovers from a panic,
+// logs the panic, writes http.StatusInternalServerError, and
+// continues to the next handler.
+//
+// Example:
+//
+//  r := mux.NewRouter()
+//  r.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+//  	panic("Unexpected error!")
+//  })
+//
+//  http.ListenAndServe(":1123", handlers.RecoveryHandler()(r))
+func RecoveryHandler(opts ...RecoveryOption) func(h http.Handler) http.Handler {
+	return func(h http.Handler) http.Handler {
+		r := &recoveryHandler{handler: h}
+		return parseRecoveryOptions(r, opts...)
+	}
+}
+
+// RecoveryLogger is a functional option to override
+// the default logger
+func RecoveryLogger(logger RecoveryHandlerLogger) RecoveryOption {
+	return func(h http.Handler) {
+		r := h.(*recoveryHandler)
+		r.logger = logger
+	}
+}
+
+// PrintRecoveryStack is a functional option to enable
+// or disable printing stack traces on panic.
+func PrintRecoveryStack(print bool) RecoveryOption {
+	return func(h http.Handler) {
+		r := h.(*recoveryHandler)
+		r.printStack = print
+	}
+}
+
+func (h recoveryHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	defer func() {
+		if err := recover(); err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			h.log(err)
+		}
+	}()
+
+	h.handler.ServeHTTP(w, req)
+}
+
+func (h recoveryHandler) log(v ...interface{}) {
+	if h.logger != nil {
+		h.logger.Println(v...)
+	} else {
+		log.Println(v...)
+	}
+
+	if h.printStack {
+		stack := string(debug.Stack())
+		if h.logger != nil {
+			h.logger.Println(stack)
+		} else {
+			log.Println(stack)
+		}
+	}
+}