Vendor some additional libraries for the tests.

vendor/github.com/gorilla/handlers/LICENSE

@@ -0,0 +1,22 @@
+Copyright (c) 2013 The Gorilla Handlers Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+  Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+  Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/gorilla/handlers/README.md

@@ -0,0 +1,52 @@
+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)
+
+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
+  Format](http://httpd.apache.org/docs/2.2/logs.html#common).
+* `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
+  content types.
+* `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
+  `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 
+  domains (i.e. multiple CNAME aliases).
+
+Other handlers are documented [on the Gorilla
+website](http://www.gorillatoolkit.org/pkg/handlers).
+
+## Example
+
+A simple example using `handlers.LoggingHandler` and `handlers.CompressHandler`:
+
+```go
+import (
+    "net/http"
+    "github.com/gorilla/handlers"
+)
+
+func main() {
+    r := http.NewServeMux()
+
+    // Only log requests to our admin dashboard to stdout
+    r.Handle("/admin", handlers.LoggingHandler(os.Stdout, http.HandlerFunc(ShowAdminDashboard)))
+    r.HandleFunc("/", ShowIndex)
+
+    // Wrap our server with our gzip handler to gzip compress all responses.
+    http.ListenAndServe(":8000", handlers.CompressHandler(r))
+}
+```
+
+## License
+
+BSD licensed. See the included LICENSE file for details.
+

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

@@ -0,0 +1,71 @@
+package handlers
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+type canonical struct {
+	h      http.Handler
+	domain string
+	code   int
+}
+
+// CanonicalHost is HTTP middleware that re-directs requests to the canonical
+// domain. It accepts a domain and a status code (e.g. 301 or 302) and
+// re-directs clients to this domain. The existing request path is maintained.
+//
+// Note: If the provided domain is considered invalid by url.Parse or otherwise
+// returns an empty scheme or host, clients are not re-directed.
+//
+// Example:
+//
+//  r := mux.NewRouter()
+//  canonical := handlers.CanonicalHost("http://www.gorillatoolkit.org", 302)
+//  r.HandleFunc("/route", YourHandler)
+//
+//  log.Fatal(http.ListenAndServe(":7000", canonical(r)))
+//
+func CanonicalHost(domain string, code int) func(h http.Handler) http.Handler {
+	fn := func(h http.Handler) http.Handler {
+		return canonical{h, domain, code}
+	}
+
+	return fn
+}
+
+func (c canonical) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	dest, err := url.Parse(c.domain)
+	if err != nil {
+		// Call the next handler if the provided domain fails to parse.
+		c.h.ServeHTTP(w, r)
+		return
+	}
+
+	if dest.Scheme == "" || dest.Host == "" {
+		// Call the next handler if the scheme or host are empty.
+		// Note that url.Parse won't fail on in this case.
+		c.h.ServeHTTP(w, r)
+		return
+	}
+
+	if !strings.EqualFold(cleanHost(r.Host), dest.Host) {
+		// Re-build the destination URL
+		dest := dest.Scheme + "://" + dest.Host + r.URL.Path
+		http.Redirect(w, r, dest, c.code)
+		return
+	}
+
+	c.h.ServeHTTP(w, r)
+}
+
+// cleanHost cleans invalid Host headers by stripping anything after '/' or ' '.
+// This is backported from Go 1.5 (in response to issue #11206) and attempts to
+// mitigate malformed Host headers that do not match the format in RFC7230.
+func cleanHost(in string) string {
+	if i := strings.IndexAny(in, " /"); i != -1 {
+		return in[:i]
+	}
+	return in
+}

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

@@ -0,0 +1,110 @@
+package handlers
+
+import (
+	"bufio"
+	"bytes"
+	"log"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestCleanHost(t *testing.T) {
+	tests := []struct {
+		in, want string
+	}{
+		{"www.google.com", "www.google.com"},
+		{"www.google.com foo", "www.google.com"},
+		{"www.google.com/foo", "www.google.com"},
+		{" first character is a space", ""},
+	}
+	for _, tt := range tests {
+		got := cleanHost(tt.in)
+		if tt.want != got {
+			t.Errorf("cleanHost(%q) = %q, want %q", tt.in, got, tt.want)
+		}
+	}
+}
+
+func TestCanonicalHost(t *testing.T) {
+	gorilla := "http://www.gorillatoolkit.org"
+
+	rr := httptest.NewRecorder()
+	r := newRequest("GET", "http://www.example.com/")
+
+	testHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})
+
+	// Test a re-direct: should return a 302 Found.
+	CanonicalHost(gorilla, http.StatusFound)(testHandler).ServeHTTP(rr, r)
+
+	if rr.Code != http.StatusFound {
+		t.Fatalf("bad status: got %v want %v", rr.Code, http.StatusFound)
+	}
+
+	if rr.Header().Get("Location") != gorilla+r.URL.Path {
+		t.Fatalf("bad re-direct: got %q want %q", rr.Header().Get("Location"), gorilla+r.URL.Path)
+	}
+
+}
+
+func TestBadDomain(t *testing.T) {
+	rr := httptest.NewRecorder()
+	r := newRequest("GET", "http://www.example.com/")
+
+	testHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})
+
+	// Test a bad domain - should return 200 OK.
+	CanonicalHost("%", http.StatusFound)(testHandler).ServeHTTP(rr, r)
+
+	if rr.Code != http.StatusOK {
+		t.Fatalf("bad status: got %v want %v", rr.Code, http.StatusOK)
+	}
+}
+
+func TestEmptyHost(t *testing.T) {
+	rr := httptest.NewRecorder()
+	r := newRequest("GET", "http://www.example.com/")
+
+	testHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})
+
+	// Test a domain that returns an empty url.Host from url.Parse.
+	CanonicalHost("hello.com", http.StatusFound)(testHandler).ServeHTTP(rr, r)
+
+	if rr.Code != http.StatusOK {
+		t.Fatalf("bad status: got %v want %v", rr.Code, http.StatusOK)
+	}
+}
+
+func TestHeaderWrites(t *testing.T) {
+	gorilla := "http://www.gorillatoolkit.org"
+
+	testHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+	})
+
+	// Catch the log output to ensure we don't write multiple headers.
+	var b bytes.Buffer
+	buf := bufio.NewWriter(&b)
+	tl := log.New(buf, "test: ", log.Lshortfile)
+
+	srv := httptest.NewServer(
+		CanonicalHost(gorilla, http.StatusFound)(testHandler))
+	defer srv.Close()
+	srv.Config.ErrorLog = tl
+
+	_, err := http.Get(srv.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = buf.Flush()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// We rely on the error not changing: net/http does not export it.
+	if strings.Contains(b.String(), "multiple response.WriteHeader calls") {
+		t.Fatalf("re-direct did not return early: multiple header writes")
+	}
+}

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

@@ -0,0 +1,104 @@
+// 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 (
+	"compress/flate"
+	"compress/gzip"
+	"io"
+	"net/http"
+	"strings"
+)
+
+type compressResponseWriter struct {
+	io.Writer
+	http.ResponseWriter
+	http.Hijacker
+}
+
+func (w *compressResponseWriter) WriteHeader(c int) {
+	w.ResponseWriter.Header().Del("Content-Length")
+	w.ResponseWriter.WriteHeader(c)
+}
+
+func (w *compressResponseWriter) Header() http.Header {
+	return w.ResponseWriter.Header()
+}
+
+func (w *compressResponseWriter) Write(b []byte) (int, error) {
+	h := w.ResponseWriter.Header()
+	if h.Get("Content-Type") == "" {
+		h.Set("Content-Type", http.DetectContentType(b))
+	}
+	h.Del("Content-Length")
+
+	return w.Writer.Write(b)
+}
+
+// CompressHandler gzip compresses HTTP responses for clients that support it
+// via the 'Accept-Encoding' header.
+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.NoCompression && (level < gzip.BestSpeed || level > gzip.BestCompression) {
+		level = gzip.DefaultCompression
+	}
+
+	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.NewWriterLevel(w, level)
+				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, level)
+				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
+			}
+		}
+
+		h.ServeHTTP(w, r)
+	})
+}

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

@@ -0,0 +1,90 @@
+// 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/http"
+	"net/http/httptest"
+	"strconv"
+	"testing"
+)
+
+var contentType = "text/plain; charset=utf-8"
+
+func compressedRequest(w *httptest.ResponseRecorder, compression string) {
+	CompressHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Length", strconv.Itoa(9*1024))
+		w.Header().Set("Content-Type", contentType)
+		for i := 0; i < 1024; i++ {
+			io.WriteString(w, "Gorilla!\n")
+		}
+	})).ServeHTTP(w, &http.Request{
+		Method: "GET",
+		Header: http.Header{
+			"Accept-Encoding": []string{compression},
+		},
+	})
+
+}
+
+func TestCompressHandlerNoCompression(t *testing.T) {
+	w := httptest.NewRecorder()
+	compressedRequest(w, "")
+	if enc := w.HeaderMap.Get("Content-Encoding"); enc != "" {
+		t.Errorf("wrong content encoding, got %q want %q", enc, "")
+	}
+	if ct := w.HeaderMap.Get("Content-Type"); ct != contentType {
+		t.Errorf("wrong content type, got %q want %q", ct, contentType)
+	}
+	if w.Body.Len() != 1024*9 {
+		t.Errorf("wrong len, got %d want %d", w.Body.Len(), 1024*9)
+	}
+	if l := w.HeaderMap.Get("Content-Length"); l != "9216" {
+		t.Errorf("wrong content-length. got %q expected %d", l, 1024*9)
+	}
+}
+
+func TestCompressHandlerGzip(t *testing.T) {
+	w := httptest.NewRecorder()
+	compressedRequest(w, "gzip")
+	if w.HeaderMap.Get("Content-Encoding") != "gzip" {
+		t.Errorf("wrong content encoding, got %q want %q", w.HeaderMap.Get("Content-Encoding"), "gzip")
+	}
+	if w.HeaderMap.Get("Content-Type") != "text/plain; charset=utf-8" {
+		t.Errorf("wrong content type, got %s want %s", w.HeaderMap.Get("Content-Type"), "text/plain; charset=utf-8")
+	}
+	if w.Body.Len() != 72 {
+		t.Errorf("wrong len, got %d want %d", w.Body.Len(), 72)
+	}
+	if l := w.HeaderMap.Get("Content-Length"); l != "" {
+		t.Errorf("wrong content-length. got %q expected %q", l, "")
+	}
+}
+
+func TestCompressHandlerDeflate(t *testing.T) {
+	w := httptest.NewRecorder()
+	compressedRequest(w, "deflate")
+	if w.HeaderMap.Get("Content-Encoding") != "deflate" {
+		t.Fatalf("wrong content encoding, got %q want %q", w.HeaderMap.Get("Content-Encoding"), "deflate")
+	}
+	if w.HeaderMap.Get("Content-Type") != "text/plain; charset=utf-8" {
+		t.Fatalf("wrong content type, got %s want %s", w.HeaderMap.Get("Content-Type"), "text/plain; charset=utf-8")
+	}
+	if w.Body.Len() != 54 {
+		t.Fatalf("wrong len, got %d want %d", w.Body.Len(), 54)
+	}
+}
+
+func TestCompressHandlerGzipDeflate(t *testing.T) {
+	w := httptest.NewRecorder()
+	compressedRequest(w, "gzip, deflate ")
+	if w.HeaderMap.Get("Content-Encoding") != "gzip" {
+		t.Fatalf("wrong content encoding, got %q want %q", w.HeaderMap.Get("Content-Encoding"), "gzip")
+	}
+	if w.HeaderMap.Get("Content-Type") != "text/plain; charset=utf-8" {
+		t.Fatalf("wrong content type, got %s want %s", w.HeaderMap.Get("Content-Type"), "text/plain; charset=utf-8")
+	}
+}

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

@@ -0,0 +1,9 @@
+/*
+Package handlers is a collection of handlers (aka "HTTP middleware") for use
+with Go's net/http package (or any framework supporting http.Handler).
+
+The package includes handlers for logging in standardised formats, compressing
+HTTP responses, validating content types and other useful tools for manipulating
+requests and responses.
+*/
+package handlers

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

@@ -0,0 +1,388 @@
+// 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 -
+//
+// 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}
+}
+
+// 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)
+	})
+}

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

@@ -0,0 +1,305 @@
+// 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 (
+	"bytes"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+)
+
+const (
+	ok         = "ok\n"
+	notAllowed = "Method not allowed\n"
+)
+
+var okHandler = http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+	w.Write([]byte(ok))
+})
+
+func newRequest(method, url string) *http.Request {
+	req, err := http.NewRequest(method, url, nil)
+	if err != nil {
+		panic(err)
+	}
+	return req
+}
+
+func TestMethodHandler(t *testing.T) {
+	tests := []struct {
+		req     *http.Request
+		handler http.Handler
+		code    int
+		allow   string // Contents of the Allow header
+		body    string
+	}{
+		// No handlers
+		{newRequest("GET", "/foo"), MethodHandler{}, http.StatusMethodNotAllowed, "", notAllowed},
+		{newRequest("OPTIONS", "/foo"), MethodHandler{}, http.StatusOK, "", ""},
+
+		// A single handler
+		{newRequest("GET", "/foo"), MethodHandler{"GET": okHandler}, http.StatusOK, "", ok},
+		{newRequest("POST", "/foo"), MethodHandler{"GET": okHandler}, http.StatusMethodNotAllowed, "GET", notAllowed},
+
+		// Multiple handlers
+		{newRequest("GET", "/foo"), MethodHandler{"GET": okHandler, "POST": okHandler}, http.StatusOK, "", ok},
+		{newRequest("POST", "/foo"), MethodHandler{"GET": okHandler, "POST": okHandler}, http.StatusOK, "", ok},
+		{newRequest("DELETE", "/foo"), MethodHandler{"GET": okHandler, "POST": okHandler}, http.StatusMethodNotAllowed, "GET, POST", notAllowed},
+		{newRequest("OPTIONS", "/foo"), MethodHandler{"GET": okHandler, "POST": okHandler}, http.StatusOK, "GET, POST", ""},
+
+		// Override OPTIONS
+		{newRequest("OPTIONS", "/foo"), MethodHandler{"OPTIONS": okHandler}, http.StatusOK, "", ok},
+	}
+
+	for i, test := range tests {
+		rec := httptest.NewRecorder()
+		test.handler.ServeHTTP(rec, test.req)
+		if rec.Code != test.code {
+			t.Fatalf("%d: wrong code, got %d want %d", i, rec.Code, test.code)
+		}
+		if allow := rec.HeaderMap.Get("Allow"); allow != test.allow {
+			t.Fatalf("%d: wrong Allow, got %s want %s", i, allow, test.allow)
+		}
+		if body := rec.Body.String(); body != test.body {
+			t.Fatalf("%d: wrong body, got %q want %q", i, body, test.body)
+		}
+	}
+}
+
+func TestWriteLog(t *testing.T) {
+	loc, err := time.LoadLocation("Europe/Warsaw")
+	if err != nil {
+		panic(err)
+	}
+	ts := time.Date(1983, 05, 26, 3, 30, 45, 0, loc)
+
+	// A typical request with an OK response
+	req := newRequest("GET", "http://example.com")
+	req.RemoteAddr = "192.168.100.5"
+
+	buf := new(bytes.Buffer)
+	writeLog(buf, req, *req.URL, ts, http.StatusOK, 100)
+	log := buf.String()
+
+	expected := "192.168.100.5 - - [26/May/1983:03:30:45 +0200] \"GET / HTTP/1.1\" 200 100\n"
+	if log != expected {
+		t.Fatalf("wrong log, got %q want %q", log, expected)
+	}
+
+	// Request with an unauthorized user
+	req = newRequest("GET", "http://example.com")
+	req.RemoteAddr = "192.168.100.5"
+	req.URL.User = url.User("kamil")
+
+	buf.Reset()
+	writeLog(buf, req, *req.URL, ts, http.StatusUnauthorized, 500)
+	log = buf.String()
+
+	expected = "192.168.100.5 - kamil [26/May/1983:03:30:45 +0200] \"GET / HTTP/1.1\" 401 500\n"
+	if log != expected {
+		t.Fatalf("wrong log, got %q want %q", log, expected)
+	}
+
+	// Request with url encoded parameters
+	req = newRequest("GET", "http://example.com/test?abc=hello%20world&a=b%3F")
+	req.RemoteAddr = "192.168.100.5"
+
+	buf.Reset()
+	writeLog(buf, req, *req.URL, ts, http.StatusOK, 100)
+	log = buf.String()
+
+	expected = "192.168.100.5 - - [26/May/1983:03:30:45 +0200] \"GET /test?abc=hello%20world&a=b%3F HTTP/1.1\" 200 100\n"
+	if log != expected {
+		t.Fatalf("wrong log, got %q want %q", log, expected)
+	}
+}
+
+func TestWriteCombinedLog(t *testing.T) {
+	loc, err := time.LoadLocation("Europe/Warsaw")
+	if err != nil {
+		panic(err)
+	}
+	ts := time.Date(1983, 05, 26, 3, 30, 45, 0, loc)
+
+	// A typical request with an OK response
+	req := newRequest("GET", "http://example.com")
+	req.RemoteAddr = "192.168.100.5"
+	req.Header.Set("Referer", "http://example.com")
+	req.Header.Set(
+		"User-Agent",
+		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) AppleWebKit/537.33 "+
+			"(KHTML, like Gecko) Chrome/27.0.1430.0 Safari/537.33",
+	)
+
+	buf := new(bytes.Buffer)
+	writeCombinedLog(buf, req, *req.URL, ts, http.StatusOK, 100)
+	log := buf.String()
+
+	expected := "192.168.100.5 - - [26/May/1983:03:30:45 +0200] \"GET / HTTP/1.1\" 200 100 \"http://example.com\" " +
+		"\"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) " +
+		"AppleWebKit/537.33 (KHTML, like Gecko) Chrome/27.0.1430.0 Safari/537.33\"\n"
+	if log != expected {
+		t.Fatalf("wrong log, got %q want %q", log, expected)
+	}
+
+	// Request with an unauthorized user
+	req.URL.User = url.User("kamil")
+
+	buf.Reset()
+	writeCombinedLog(buf, req, *req.URL, ts, http.StatusUnauthorized, 500)
+	log = buf.String()
+
+	expected = "192.168.100.5 - kamil [26/May/1983:03:30:45 +0200] \"GET / HTTP/1.1\" 401 500 \"http://example.com\" " +
+		"\"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) " +
+		"AppleWebKit/537.33 (KHTML, like Gecko) Chrome/27.0.1430.0 Safari/537.33\"\n"
+	if log != expected {
+		t.Fatalf("wrong log, got %q want %q", log, expected)
+	}
+
+	// Test with remote ipv6 address
+	req.RemoteAddr = "::1"
+
+	buf.Reset()
+	writeCombinedLog(buf, req, *req.URL, ts, http.StatusOK, 100)
+	log = buf.String()
+
+	expected = "::1 - kamil [26/May/1983:03:30:45 +0200] \"GET / HTTP/1.1\" 200 100 \"http://example.com\" " +
+		"\"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) " +
+		"AppleWebKit/537.33 (KHTML, like Gecko) Chrome/27.0.1430.0 Safari/537.33\"\n"
+	if log != expected {
+		t.Fatalf("wrong log, got %q want %q", log, expected)
+	}
+
+	// Test remote ipv6 addr, with port
+	req.RemoteAddr = net.JoinHostPort("::1", "65000")
+
+	buf.Reset()
+	writeCombinedLog(buf, req, *req.URL, ts, http.StatusOK, 100)
+	log = buf.String()
+
+	expected = "::1 - kamil [26/May/1983:03:30:45 +0200] \"GET / HTTP/1.1\" 200 100 \"http://example.com\" " +
+		"\"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) " +
+		"AppleWebKit/537.33 (KHTML, like Gecko) Chrome/27.0.1430.0 Safari/537.33\"\n"
+	if log != expected {
+		t.Fatalf("wrong log, got %q want %q", log, expected)
+	}
+}
+
+func TestLogPathRewrites(t *testing.T) {
+	var buf bytes.Buffer
+
+	handler := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		req.URL.Path = "/" // simulate http.StripPrefix and friends
+		w.WriteHeader(200)
+	})
+	logger := LoggingHandler(&buf, handler)
+
+	logger.ServeHTTP(httptest.NewRecorder(), newRequest("GET", "/subdir/asdf"))
+
+	if !strings.Contains(buf.String(), "GET /subdir/asdf HTTP") {
+		t.Fatalf("Got log %#v, wanted substring %#v", buf.String(), "GET /subdir/asdf HTTP")
+	}
+}
+
+func BenchmarkWriteLog(b *testing.B) {
+	loc, err := time.LoadLocation("Europe/Warsaw")
+	if err != nil {
+		b.Fatalf(err.Error())
+	}
+	ts := time.Date(1983, 05, 26, 3, 30, 45, 0, loc)
+
+	req := newRequest("GET", "http://example.com")
+	req.RemoteAddr = "192.168.100.5"
+
+	b.ResetTimer()
+
+	buf := &bytes.Buffer{}
+	for i := 0; i < b.N; i++ {
+		buf.Reset()
+		writeLog(buf, req, *req.URL, ts, http.StatusUnauthorized, 500)
+	}
+}
+
+func TestContentTypeHandler(t *testing.T) {
+	tests := []struct {
+		Method            string
+		AllowContentTypes []string
+		ContentType       string
+		Code              int
+	}{
+		{"POST", []string{"application/json"}, "application/json", http.StatusOK},
+		{"POST", []string{"application/json", "application/xml"}, "application/json", http.StatusOK},
+		{"POST", []string{"application/json"}, "application/json; charset=utf-8", http.StatusOK},
+		{"POST", []string{"application/json"}, "application/json+xxx", http.StatusUnsupportedMediaType},
+		{"POST", []string{"application/json"}, "text/plain", http.StatusUnsupportedMediaType},
+		{"GET", []string{"application/json"}, "", http.StatusOK},
+		{"GET", []string{}, "", http.StatusOK},
+	}
+	for _, test := range tests {
+		r, err := http.NewRequest(test.Method, "/", nil)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		h := ContentTypeHandler(okHandler, test.AllowContentTypes...)
+		r.Header.Set("Content-Type", test.ContentType)
+		w := httptest.NewRecorder()
+		h.ServeHTTP(w, r)
+		if w.Code != test.Code {
+			t.Errorf("expected %d, got %d", test.Code, w.Code)
+		}
+	}
+}
+
+func TestHTTPMethodOverride(t *testing.T) {
+	var tests = []struct {
+		Method         string
+		OverrideMethod string
+		ExpectedMethod string
+	}{
+		{"POST", "PUT", "PUT"},
+		{"POST", "PATCH", "PATCH"},
+		{"POST", "DELETE", "DELETE"},
+		{"PUT", "DELETE", "PUT"},
+		{"GET", "GET", "GET"},
+		{"HEAD", "HEAD", "HEAD"},
+		{"GET", "PUT", "GET"},
+		{"HEAD", "DELETE", "HEAD"},
+	}
+
+	for _, test := range tests {
+		h := HTTPMethodOverrideHandler(okHandler)
+		reqs := make([]*http.Request, 0, 2)
+
+		rHeader, err := http.NewRequest(test.Method, "/", nil)
+		if err != nil {
+			t.Error(err)
+		}
+		rHeader.Header.Set(HTTPMethodOverrideHeader, test.OverrideMethod)
+		reqs = append(reqs, rHeader)
+
+		f := url.Values{HTTPMethodOverrideFormKey: []string{test.OverrideMethod}}
+		rForm, err := http.NewRequest(test.Method, "/", strings.NewReader(f.Encode()))
+		if err != nil {
+			t.Error(err)
+		}
+		rForm.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+		reqs = append(reqs, rForm)
+
+		for _, r := range reqs {
+			w := httptest.NewRecorder()
+			h.ServeHTTP(w, r)
+			if r.Method != test.ExpectedMethod {
+				t.Errorf("Expected %s, got %s", test.ExpectedMethod, r.Method)
+			}
+		}
+	}
+}

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

@@ -0,0 +1,113 @@
+package handlers
+
+import (
+	"net/http"
+	"regexp"
+	"strings"
+)
+
+var (
+	// De-facto standard header keys.
+	xForwardedFor   = http.CanonicalHeaderKey("X-Forwarded-For")
+	xRealIP         = http.CanonicalHeaderKey("X-Real-IP")
+	xForwardedProto = http.CanonicalHeaderKey("X-Forwarded-Scheme")
+)
+
+var (
+	// RFC7239 defines a new "Forwarded: " header designed to replace the
+	// existing use of X-Forwarded-* headers.
+	// e.g. Forwarded: for=192.0.2.60;proto=https;by=203.0.113.43
+	forwarded = http.CanonicalHeaderKey("Forwarded")
+	// Allows for a sub-match of the first value after 'for=' to the next
+	// comma, semi-colon or space. The match is case-insensitive.
+	forRegex = regexp.MustCompile(`(?i)(?:for=)([^(;|,| )]+)`)
+	// Allows for a sub-match for the first instance of scheme (http|https)
+	// prefixed by 'proto='. The match is case-insensitive.
+	protoRegex = regexp.MustCompile(`(?i)(?:proto=)(https|http)`)
+)
+
+// 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.
+//
+// NOTE: This middleware should only be used when behind a reverse
+// proxy like nginx, HAProxy or Apache. Reverse proxies that don't (or are
+// configured not to) strip these headers from client requests, or where these
+// headers are accepted "as is" from a remote client (e.g. when Go is not behind
+// a proxy), can manifest as a vulnerability if your application uses these
+// headers for validating the 'trustworthiness' of a request.
+func ProxyHeaders(h http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		// Set the remote IP with the value passed from the proxy.
+		if fwd := getIP(r); fwd != "" {
+			r.RemoteAddr = fwd
+		}
+
+		// Set the scheme (proto) with the value passed from the proxy.
+		if scheme := getScheme(r); scheme != "" {
+			r.URL.Scheme = scheme
+		}
+
+		// Call the next handler in the chain.
+		h.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(fn)
+}
+
+// getIP retrieves the IP from the X-Forwarded-For, X-Real-IP and RFC7239
+// Forwarded headers (in that order).
+func getIP(r *http.Request) string {
+	var addr string
+
+	if fwd := r.Header.Get(xForwardedFor); fwd != "" {
+		// Only grab the first (client) address. Note that '192.168.0.1,
+		// 10.1.1.1' is a valid key for X-Forwarded-For where addresses after
+		// the first may represent forwarding proxies earlier in the chain.
+		s := strings.Index(fwd, ", ")
+		if s == -1 {
+			s = len(fwd)
+		}
+		addr = fwd[:s]
+	} else if fwd := r.Header.Get(xRealIP); fwd != "" {
+		// X-Real-IP should only contain one IP address (the client making the
+		// request).
+		addr = fwd
+	} else if fwd := r.Header.Get(forwarded); fwd != "" {
+		// match should contain at least two elements if the protocol was
+		// specified in the Forwarded header. The first element will always be
+		// the 'for=' capture, which we ignore. In the case of multiple IP
+		// addresses (for=8.8.8.8, 8.8.4.4,172.16.1.20 is valid) we only
+		// extract the first, which should be the client IP.
+		if match := forRegex.FindStringSubmatch(fwd); len(match) > 1 {
+			// IPv6 addresses in Forwarded headers are quoted-strings. We strip
+			// these quotes.
+			addr = strings.Trim(match[1], `"`)
+		}
+	}
+
+	return addr
+}
+
+// getScheme retrieves the scheme from the X-Forwarded-Proto and RFC7239
+// Forwarded headers (in that order).
+func getScheme(r *http.Request) string {
+	var scheme 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 != "" {
+		// 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
+		// parameters (invalid) we only extract the first.
+		if match := protoRegex.FindStringSubmatch(proto); len(match) > 1 {
+			scheme = strings.ToLower(match[1])
+		}
+	}
+
+	return scheme
+}

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

@@ -0,0 +1,100 @@
+package handlers
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+type headerTable struct {
+	key      string // header key
+	val      string // header val
+	expected string // expected result
+}
+
+func TestGetIP(t *testing.T) {
+	headers := []headerTable{
+		{xForwardedFor, "8.8.8.8", "8.8.8.8"},                                         // Single address
+		{xForwardedFor, "8.8.8.8, 8.8.4.4", "8.8.8.8"},                                // Multiple
+		{xForwardedFor, "[2001:db8:cafe::17]:4711", "[2001:db8:cafe::17]:4711"},       // IPv6 address
+		{xForwardedFor, "", ""},                                                       // None
+		{xRealIP, "8.8.8.8", "8.8.8.8"},                                               // Single address
+		{xRealIP, "8.8.8.8, 8.8.4.4", "8.8.8.8, 8.8.4.4"},                             // Multiple
+		{xRealIP, "[2001:db8:cafe::17]:4711", "[2001:db8:cafe::17]:4711"},             // IPv6 address
+		{xRealIP, "", ""},                                                             // None
+		{forwarded, `for="_gazonk"`, "_gazonk"},                                       // Hostname
+		{forwarded, `For="[2001:db8:cafe::17]:4711`, `[2001:db8:cafe::17]:4711`},      // IPv6 address
+		{forwarded, `for=192.0.2.60;proto=http;by=203.0.113.43`, `192.0.2.60`},        // Multiple params
+		{forwarded, `for=192.0.2.43, for=198.51.100.17`, "192.0.2.43"},                // Multiple params
+		{forwarded, `for="workstation.local",for=198.51.100.17`, "workstation.local"}, // Hostname
+	}
+
+	for _, v := range headers {
+		req := &http.Request{
+			Header: http.Header{
+				v.key: []string{v.val},
+			}}
+		res := getIP(req)
+		if res != v.expected {
+			t.Fatalf("wrong header for %s: got %s want %s", v.key, res,
+				v.expected)
+		}
+	}
+}
+
+func TestGetScheme(t *testing.T) {
+	headers := []headerTable{
+		{xForwardedProto, "https", "https"},
+		{xForwardedProto, "http", "http"},
+		{xForwardedProto, "HTTP", "http"},
+		{forwarded, `For="[2001:db8:cafe::17]:4711`, ""},                      // No proto
+		{forwarded, `for=192.0.2.43, for=198.51.100.17;proto=https`, "https"}, // Multiple params before proto
+		{forwarded, `for=172.32.10.15; proto=https;by=127.0.0.1`, "https"},    // Space before proto
+		{forwarded, `for=192.0.2.60;proto=http;by=203.0.113.43`, "http"},      // Multiple params
+	}
+
+	for _, v := range headers {
+		req := &http.Request{
+			Header: http.Header{
+				v.key: []string{v.val},
+			},
+		}
+		res := getScheme(req)
+		if res != v.expected {
+			t.Fatalf("wrong header for %s: got %s want %s", v.key, res,
+				v.expected)
+		}
+	}
+}
+
+// Test the middleware end-to-end
+func TestProxyHeaders(t *testing.T) {
+	rr := httptest.NewRecorder()
+	r := newRequest("GET", "/")
+
+	r.Header.Set(xForwardedFor, "8.8.8.8")
+	r.Header.Set(xForwardedProto, "https")
+
+	var addr string
+	var proto string
+	ProxyHeaders(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			addr = r.RemoteAddr
+			proto = r.URL.Scheme
+		})).ServeHTTP(rr, r)
+
+	if rr.Code != http.StatusOK {
+		t.Fatalf("bad status: got %d want %d", rr.Code, http.StatusOK)
+	}
+
+	if addr != r.Header.Get(xForwardedFor) {
+		t.Fatalf("wrong address: got %s want %s", addr,
+			r.Header.Get(xForwardedFor))
+	}
+
+	if proto != r.Header.Get(xForwardedProto) {
+		t.Fatalf("wrong address: got %s want %s", proto,
+			r.Header.Get(xForwardedProto))
+	}
+
+}

vendor/github.com/pmezard/go-difflib/difflib/difflib.go

@@ -0,0 +1,758 @@
+// Package difflib is a partial port of Python difflib module.
+//
+// It provides tools to compare sequences of strings and generate textual diffs.
+//
+// The following class and functions have been ported:
+//
+// - SequenceMatcher
+//
+// - unified_diff
+//
+// - context_diff
+//
+// Getting unified diffs was the main goal of the port. Keep in mind this code
+// is mostly suitable to output text differences in a human friendly way, there
+// are no guarantees generated diffs are consumable by patch(1).
+package difflib
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+)
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func calculateRatio(matches, length int) float64 {
+	if length > 0 {
+		return 2.0 * float64(matches) / float64(length)
+	}
+	return 1.0
+}
+
+type Match struct {
+	A    int
+	B    int
+	Size int
+}
+
+type OpCode struct {
+	Tag byte
+	I1  int
+	I2  int
+	J1  int
+	J2  int
+}
+
+// SequenceMatcher compares sequence of strings. The basic
+// algorithm predates, and is a little fancier than, an algorithm
+// published in the late 1980's by Ratcliff and Obershelp under the
+// hyperbolic name "gestalt pattern matching".  The basic idea is to find
+// the longest contiguous matching subsequence that contains no "junk"
+// elements (R-O doesn't address junk).  The same idea is then applied
+// recursively to the pieces of the sequences to the left and to the right
+// of the matching subsequence.  This does not yield minimal edit
+// sequences, but does tend to yield matches that "look right" to people.
+//
+// SequenceMatcher tries to compute a "human-friendly diff" between two
+// sequences.  Unlike e.g. UNIX(tm) diff, the fundamental notion is the
+// longest *contiguous* & junk-free matching subsequence.  That's what
+// catches peoples' eyes.  The Windows(tm) windiff has another interesting
+// notion, pairing up elements that appear uniquely in each sequence.
+// That, and the method here, appear to yield more intuitive difference
+// reports than does diff.  This method appears to be the least vulnerable
+// to synching up on blocks of "junk lines", though (like blank lines in
+// ordinary text files, or maybe "<P>" lines in HTML files).  That may be
+// because this is the only method of the 3 that has a *concept* of
+// "junk" <wink>.
+//
+// Timing:  Basic R-O is cubic time worst case and quadratic time expected
+// case.  SequenceMatcher is quadratic time for the worst case and has
+// expected-case behavior dependent in a complicated way on how many
+// elements the sequences have in common; best case time is linear.
+type SequenceMatcher struct {
+	a              []string
+	b              []string
+	b2j            map[string][]int
+	IsJunk         func(string) bool
+	autoJunk       bool
+	bJunk          map[string]struct{}
+	matchingBlocks []Match
+	fullBCount     map[string]int
+	bPopular       map[string]struct{}
+	opCodes        []OpCode
+}
+
+func NewMatcher(a, b []string) *SequenceMatcher {
+	m := SequenceMatcher{autoJunk: true}
+	m.SetSeqs(a, b)
+	return &m
+}
+
+func NewMatcherWithJunk(a, b []string, autoJunk bool,
+	isJunk func(string) bool) *SequenceMatcher {
+
+	m := SequenceMatcher{IsJunk: isJunk, autoJunk: autoJunk}
+	m.SetSeqs(a, b)
+	return &m
+}
+
+// Set two sequences to be compared.
+func (m *SequenceMatcher) SetSeqs(a, b []string) {
+	m.SetSeq1(a)
+	m.SetSeq2(b)
+}
+
+// Set the first sequence to be compared. The second sequence to be compared is
+// not changed.
+//
+// SequenceMatcher computes and caches detailed information about the second
+// sequence, so if you want to compare one sequence S against many sequences,
+// use .SetSeq2(s) once and call .SetSeq1(x) repeatedly for each of the other
+// sequences.
+//
+// See also SetSeqs() and SetSeq2().
+func (m *SequenceMatcher) SetSeq1(a []string) {
+	if &a == &m.a {
+		return
+	}
+	m.a = a
+	m.matchingBlocks = nil
+	m.opCodes = nil
+}
+
+// Set the second sequence to be compared. The first sequence to be compared is
+// not changed.
+func (m *SequenceMatcher) SetSeq2(b []string) {
+	if &b == &m.b {
+		return
+	}
+	m.b = b
+	m.matchingBlocks = nil
+	m.opCodes = nil
+	m.fullBCount = nil
+	m.chainB()
+}
+
+func (m *SequenceMatcher) chainB() {
+	// Populate line -> index mapping
+	b2j := map[string][]int{}
+	for i, s := range m.b {
+		indices := b2j[s]
+		indices = append(indices, i)
+		b2j[s] = indices
+	}
+
+	// Purge junk elements
+	m.bJunk = map[string]struct{}{}
+	if m.IsJunk != nil {
+		junk := m.bJunk
+		for s, _ := range b2j {
+			if m.IsJunk(s) {
+				junk[s] = struct{}{}
+			}
+		}
+		for s, _ := range junk {
+			delete(b2j, s)
+		}
+	}
+
+	// Purge remaining popular elements
+	popular := map[string]struct{}{}
+	n := len(m.b)
+	if m.autoJunk && n >= 200 {
+		ntest := n/100 + 1
+		for s, indices := range b2j {
+			if len(indices) > ntest {
+				popular[s] = struct{}{}
+			}
+		}
+		for s, _ := range popular {
+			delete(b2j, s)
+		}
+	}
+	m.bPopular = popular
+	m.b2j = b2j
+}
+
+func (m *SequenceMatcher) isBJunk(s string) bool {
+	_, ok := m.bJunk[s]
+	return ok
+}
+
+// Find longest matching block in a[alo:ahi] and b[blo:bhi].
+//
+// If IsJunk is not defined:
+//
+// Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
+//     alo <= i <= i+k <= ahi
+//     blo <= j <= j+k <= bhi
+// and for all (i',j',k') meeting those conditions,
+//     k >= k'
+//     i <= i'
+//     and if i == i', j <= j'
+//
+// In other words, of all maximal matching blocks, return one that
+// starts earliest in a, and of all those maximal matching blocks that
+// start earliest in a, return the one that starts earliest in b.
+//
+// If IsJunk is defined, first the longest matching block is
+// determined as above, but with the additional restriction that no
+// junk element appears in the block.  Then that block is extended as
+// far as possible by matching (only) junk elements on both sides.  So
+// the resulting block never matches on junk except as identical junk
+// happens to be adjacent to an "interesting" match.
+//
+// If no blocks match, return (alo, blo, 0).
+func (m *SequenceMatcher) findLongestMatch(alo, ahi, blo, bhi int) Match {
+	// CAUTION:  stripping common prefix or suffix would be incorrect.
+	// E.g.,
+	//    ab
+	//    acab
+	// Longest matching block is "ab", but if common prefix is
+	// stripped, it's "a" (tied with "b").  UNIX(tm) diff does so
+	// strip, so ends up claiming that ab is changed to acab by
+	// inserting "ca" in the middle.  That's minimal but unintuitive:
+	// "it's obvious" that someone inserted "ac" at the front.
+	// Windiff ends up at the same place as diff, but by pairing up
+	// the unique 'b's and then matching the first two 'a's.
+	besti, bestj, bestsize := alo, blo, 0
+
+	// find longest junk-free match
+	// during an iteration of the loop, j2len[j] = length of longest
+	// junk-free match ending with a[i-1] and b[j]
+	j2len := map[int]int{}
+	for i := alo; i != ahi; i++ {
+		// look at all instances of a[i] in b; note that because
+		// b2j has no junk keys, the loop is skipped if a[i] is junk
+		newj2len := map[int]int{}
+		for _, j := range m.b2j[m.a[i]] {
+			// a[i] matches b[j]
+			if j < blo {
+				continue
+			}
+			if j >= bhi {
+				break
+			}
+			k := j2len[j-1] + 1
+			newj2len[j] = k
+			if k > bestsize {
+				besti, bestj, bestsize = i-k+1, j-k+1, k
+			}
+		}
+		j2len = newj2len
+	}
+
+	// Extend the best by non-junk elements on each end.  In particular,
+	// "popular" non-junk elements aren't in b2j, which greatly speeds
+	// the inner loop above, but also means "the best" match so far
+	// doesn't contain any junk *or* popular non-junk elements.
+	for besti > alo && bestj > blo && !m.isBJunk(m.b[bestj-1]) &&
+		m.a[besti-1] == m.b[bestj-1] {
+		besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+	}
+	for besti+bestsize < ahi && bestj+bestsize < bhi &&
+		!m.isBJunk(m.b[bestj+bestsize]) &&
+		m.a[besti+bestsize] == m.b[bestj+bestsize] {
+		bestsize += 1
+	}
+
+	// Now that we have a wholly interesting match (albeit possibly
+	// empty!), we may as well suck up the matching junk on each
+	// side of it too.  Can't think of a good reason not to, and it
+	// saves post-processing the (possibly considerable) expense of
+	// figuring out what to do with it.  In the case of an empty
+	// interesting match, this is clearly the right thing to do,
+	// because no other kind of match is possible in the regions.
+	for besti > alo && bestj > blo && m.isBJunk(m.b[bestj-1]) &&
+		m.a[besti-1] == m.b[bestj-1] {
+		besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+	}
+	for besti+bestsize < ahi && bestj+bestsize < bhi &&
+		m.isBJunk(m.b[bestj+bestsize]) &&
+		m.a[besti+bestsize] == m.b[bestj+bestsize] {
+		bestsize += 1
+	}
+
+	return Match{A: besti, B: bestj, Size: bestsize}
+}
+
+// Return list of triples describing matching subsequences.
+//
+// Each triple is of the form (i, j, n), and means that
+// a[i:i+n] == b[j:j+n].  The triples are monotonically increasing in
+// i and in j. It's also guaranteed that if (i, j, n) and (i', j', n') are
+// adjacent triples in the list, and the second is not the last triple in the
+// list, then i+n != i' or j+n != j'. IOW, adjacent triples never describe
+// adjacent equal blocks.
+//
+// The last triple is a dummy, (len(a), len(b), 0), and is the only
+// triple with n==0.
+func (m *SequenceMatcher) GetMatchingBlocks() []Match {
+	if m.matchingBlocks != nil {
+		return m.matchingBlocks
+	}
+
+	var matchBlocks func(alo, ahi, blo, bhi int, matched []Match) []Match
+	matchBlocks = func(alo, ahi, blo, bhi int, matched []Match) []Match {
+		match := m.findLongestMatch(alo, ahi, blo, bhi)
+		i, j, k := match.A, match.B, match.Size
+		if match.Size > 0 {
+			if alo < i && blo < j {
+				matched = matchBlocks(alo, i, blo, j, matched)
+			}
+			matched = append(matched, match)
+			if i+k < ahi && j+k < bhi {
+				matched = matchBlocks(i+k, ahi, j+k, bhi, matched)
+			}
+		}
+		return matched
+	}
+	matched := matchBlocks(0, len(m.a), 0, len(m.b), nil)
+
+	// It's possible that we have adjacent equal blocks in the
+	// matching_blocks list now.
+	nonAdjacent := []Match{}
+	i1, j1, k1 := 0, 0, 0
+	for _, b := range matched {
+		// Is this block adjacent to i1, j1, k1?
+		i2, j2, k2 := b.A, b.B, b.Size
+		if i1+k1 == i2 && j1+k1 == j2 {
+			// Yes, so collapse them -- this just increases the length of
+			// the first block by the length of the second, and the first
+			// block so lengthened remains the block to compare against.
+			k1 += k2
+		} else {
+			// Not adjacent.  Remember the first block (k1==0 means it's
+			// the dummy we started with), and make the second block the
+			// new block to compare against.
+			if k1 > 0 {
+				nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
+			}
+			i1, j1, k1 = i2, j2, k2
+		}
+	}
+	if k1 > 0 {
+		nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
+	}
+
+	nonAdjacent = append(nonAdjacent, Match{len(m.a), len(m.b), 0})
+	m.matchingBlocks = nonAdjacent
+	return m.matchingBlocks
+}
+
+// Return list of 5-tuples describing how to turn a into b.
+//
+// Each tuple is of the form (tag, i1, i2, j1, j2).  The first tuple
+// has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the
+// tuple preceding it, and likewise for j1 == the previous j2.
+//
+// The tags are characters, with these meanings:
+//
+// 'r' (replace):  a[i1:i2] should be replaced by b[j1:j2]
+//
+// 'd' (delete):   a[i1:i2] should be deleted, j1==j2 in this case.
+//
+// 'i' (insert):   b[j1:j2] should be inserted at a[i1:i1], i1==i2 in this case.
+//
+// 'e' (equal):    a[i1:i2] == b[j1:j2]
+func (m *SequenceMatcher) GetOpCodes() []OpCode {
+	if m.opCodes != nil {
+		return m.opCodes
+	}
+	i, j := 0, 0
+	matching := m.GetMatchingBlocks()
+	opCodes := make([]OpCode, 0, len(matching))
+	for _, m := range matching {
+		//  invariant:  we've pumped out correct diffs to change
+		//  a[:i] into b[:j], and the next matching block is
+		//  a[ai:ai+size] == b[bj:bj+size]. So we need to pump
+		//  out a diff to change a[i:ai] into b[j:bj], pump out
+		//  the matching block, and move (i,j) beyond the match
+		ai, bj, size := m.A, m.B, m.Size
+		tag := byte(0)
+		if i < ai && j < bj {
+			tag = 'r'
+		} else if i < ai {
+			tag = 'd'
+		} else if j < bj {
+			tag = 'i'
+		}
+		if tag > 0 {
+			opCodes = append(opCodes, OpCode{tag, i, ai, j, bj})
+		}
+		i, j = ai+size, bj+size
+		// the list of matching blocks is terminated by a
+		// sentinel with size 0
+		if size > 0 {
+			opCodes = append(opCodes, OpCode{'e', ai, i, bj, j})
+		}
+	}
+	m.opCodes = opCodes
+	return m.opCodes
+}
+
+// Isolate change clusters by eliminating ranges with no changes.
+//
+// Return a generator of groups with up to n lines of context.
+// Each group is in the same format as returned by GetOpCodes().
+func (m *SequenceMatcher) GetGroupedOpCodes(n int) [][]OpCode {
+	if n < 0 {
+		n = 3
+	}
+	codes := m.GetOpCodes()
+	if len(codes) == 0 {
+		codes = []OpCode{OpCode{'e', 0, 1, 0, 1}}
+	}
+	// Fixup leading and trailing groups if they show no changes.
+	if codes[0].Tag == 'e' {
+		c := codes[0]
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		codes[0] = OpCode{c.Tag, max(i1, i2-n), i2, max(j1, j2-n), j2}
+	}
+	if codes[len(codes)-1].Tag == 'e' {
+		c := codes[len(codes)-1]
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		codes[len(codes)-1] = OpCode{c.Tag, i1, min(i2, i1+n), j1, min(j2, j1+n)}
+	}
+	nn := n + n
+	groups := [][]OpCode{}
+	group := []OpCode{}
+	for _, c := range codes {
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		// End the current group and start a new one whenever
+		// there is a large range with no changes.
+		if c.Tag == 'e' && i2-i1 > nn {
+			group = append(group, OpCode{c.Tag, i1, min(i2, i1+n),
+				j1, min(j2, j1+n)})
+			groups = append(groups, group)
+			group = []OpCode{}
+			i1, j1 = max(i1, i2-n), max(j1, j2-n)
+		}
+		group = append(group, OpCode{c.Tag, i1, i2, j1, j2})
+	}
+	if len(group) > 0 && !(len(group) == 1 && group[0].Tag == 'e') {
+		groups = append(groups, group)
+	}
+	return groups
+}
+
+// Return a measure of the sequences' similarity (float in [0,1]).
+//
+// Where T is the total number of elements in both sequences, and
+// M is the number of matches, this is 2.0*M / T.
+// Note that this is 1 if the sequences are identical, and 0 if
+// they have nothing in common.
+//
+// .Ratio() is expensive to compute if you haven't already computed
+// .GetMatchingBlocks() or .GetOpCodes(), in which case you may
+// want to try .QuickRatio() or .RealQuickRation() first to get an
+// upper bound.
+func (m *SequenceMatcher) Ratio() float64 {
+	matches := 0
+	for _, m := range m.GetMatchingBlocks() {
+		matches += m.Size
+	}
+	return calculateRatio(matches, len(m.a)+len(m.b))
+}
+
+// Return an upper bound on ratio() relatively quickly.
+//
+// This isn't defined beyond that it is an upper bound on .Ratio(), and
+// is faster to compute.
+func (m *SequenceMatcher) QuickRatio() float64 {
+	// viewing a and b as multisets, set matches to the cardinality
+	// of their intersection; this counts the number of matches
+	// without regard to order, so is clearly an upper bound
+	if m.fullBCount == nil {
+		m.fullBCount = map[string]int{}
+		for _, s := range m.b {
+			m.fullBCount[s] = m.fullBCount[s] + 1
+		}
+	}
+
+	// avail[x] is the number of times x appears in 'b' less the
+	// number of times we've seen it in 'a' so far ... kinda
+	avail := map[string]int{}
+	matches := 0
+	for _, s := range m.a {
+		n, ok := avail[s]
+		if !ok {
+			n = m.fullBCount[s]
+		}
+		avail[s] = n - 1
+		if n > 0 {
+			matches += 1
+		}
+	}
+	return calculateRatio(matches, len(m.a)+len(m.b))
+}
+
+// Return an upper bound on ratio() very quickly.
+//
+// This isn't defined beyond that it is an upper bound on .Ratio(), and
+// is faster to compute than either .Ratio() or .QuickRatio().
+func (m *SequenceMatcher) RealQuickRatio() float64 {
+	la, lb := len(m.a), len(m.b)
+	return calculateRatio(min(la, lb), la+lb)
+}
+
+// Convert range to the "ed" format
+func formatRangeUnified(start, stop int) string {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	beginning := start + 1 // lines start numbering with one
+	length := stop - start
+	if length == 1 {
+		return fmt.Sprintf("%d", beginning)
+	}
+	if length == 0 {
+		beginning -= 1 // empty ranges begin at line just before the range
+	}
+	return fmt.Sprintf("%d,%d", beginning, length)
+}
+
+// Unified diff parameters
+type UnifiedDiff struct {
+	A        []string // First sequence lines
+	FromFile string   // First file name
+	FromDate string   // First file time
+	B        []string // Second sequence lines
+	ToFile   string   // Second file name
+	ToDate   string   // Second file time
+	Eol      string   // Headers end of line, defaults to LF
+	Context  int      // Number of context lines
+}
+
+// Compare two sequences of lines; generate the delta as a unified diff.
+//
+// Unified diffs are a compact way of showing line changes and a few
+// lines of context.  The number of context lines is set by 'n' which
+// defaults to three.
+//
+// By default, the diff control lines (those with ---, +++, or @@) are
+// created with a trailing newline.  This is helpful so that inputs
+// created from file.readlines() result in diffs that are suitable for
+// file.writelines() since both the inputs and outputs have trailing
+// newlines.
+//
+// For inputs that do not have trailing newlines, set the lineterm
+// argument to "" so that the output will be uniformly newline free.
+//
+// The unidiff format normally has a header for filenames and modification
+// times.  Any or all of these may be specified using strings for
+// 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
+// The modification times are normally expressed in the ISO 8601 format.
+func WriteUnifiedDiff(writer io.Writer, diff UnifiedDiff) error {
+	buf := bufio.NewWriter(writer)
+	defer buf.Flush()
+	w := func(format string, args ...interface{}) error {
+		_, err := buf.WriteString(fmt.Sprintf(format, args...))
+		return err
+	}
+
+	if len(diff.Eol) == 0 {
+		diff.Eol = "\n"
+	}
+
+	started := false
+	m := NewMatcher(diff.A, diff.B)
+	for _, g := range m.GetGroupedOpCodes(diff.Context) {
+		if !started {
+			started = true
+			fromDate := ""
+			if len(diff.FromDate) > 0 {
+				fromDate = "\t" + diff.FromDate
+			}
+			toDate := ""
+			if len(diff.ToDate) > 0 {
+				toDate = "\t" + diff.ToDate
+			}
+			err := w("--- %s%s%s", diff.FromFile, fromDate, diff.Eol)
+			if err != nil {
+				return err
+			}
+			err = w("+++ %s%s%s", diff.ToFile, toDate, diff.Eol)
+			if err != nil {
+				return err
+			}
+		}
+		first, last := g[0], g[len(g)-1]
+		range1 := formatRangeUnified(first.I1, last.I2)
+		range2 := formatRangeUnified(first.J1, last.J2)
+		if err := w("@@ -%s +%s @@%s", range1, range2, diff.Eol); err != nil {
+			return err
+		}
+		for _, c := range g {
+			i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+			if c.Tag == 'e' {
+				for _, line := range diff.A[i1:i2] {
+					if err := w(" " + line); err != nil {
+						return err
+					}
+				}
+				continue
+			}
+			if c.Tag == 'r' || c.Tag == 'd' {
+				for _, line := range diff.A[i1:i2] {
+					if err := w("-" + line); err != nil {
+						return err
+					}
+				}
+			}
+			if c.Tag == 'r' || c.Tag == 'i' {
+				for _, line := range diff.B[j1:j2] {
+					if err := w("+" + line); err != nil {
+						return err
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// Like WriteUnifiedDiff but returns the diff a string.
+func GetUnifiedDiffString(diff UnifiedDiff) (string, error) {
+	w := &bytes.Buffer{}
+	err := WriteUnifiedDiff(w, diff)
+	return string(w.Bytes()), err
+}
+
+// Convert range to the "ed" format.
+func formatRangeContext(start, stop int) string {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	beginning := start + 1 // lines start numbering with one
+	length := stop - start
+	if length == 0 {
+		beginning -= 1 // empty ranges begin at line just before the range
+	}
+	if length <= 1 {
+		return fmt.Sprintf("%d", beginning)
+	}
+	return fmt.Sprintf("%d,%d", beginning, beginning+length-1)
+}
+
+type ContextDiff UnifiedDiff
+
+// Compare two sequences of lines; generate the delta as a context diff.
+//
+// Context diffs are a compact way of showing line changes and a few
+// lines of context. The number of context lines is set by diff.Context
+// which defaults to three.
+//
+// By default, the diff control lines (those with *** or ---) are
+// created with a trailing newline.
+//
+// For inputs that do not have trailing newlines, set the diff.Eol
+// argument to "" so that the output will be uniformly newline free.
+//
+// The context diff format normally has a header for filenames and
+// modification times.  Any or all of these may be specified using
+// strings for diff.FromFile, diff.ToFile, diff.FromDate, diff.ToDate.
+// The modification times are normally expressed in the ISO 8601 format.
+// If not specified, the strings default to blanks.
+func WriteContextDiff(writer io.Writer, diff ContextDiff) error {
+	buf := bufio.NewWriter(writer)
+	defer buf.Flush()
+	var diffErr error
+	w := func(format string, args ...interface{}) {
+		_, err := buf.WriteString(fmt.Sprintf(format, args...))
+		if diffErr == nil && err != nil {
+			diffErr = err
+		}
+	}
+
+	if len(diff.Eol) == 0 {
+		diff.Eol = "\n"
+	}
+
+	prefix := map[byte]string{
+		'i': "+ ",
+		'd': "- ",
+		'r': "! ",
+		'e': "  ",
+	}
+
+	started := false
+	m := NewMatcher(diff.A, diff.B)
+	for _, g := range m.GetGroupedOpCodes(diff.Context) {
+		if !started {
+			started = true
+			fromDate := ""
+			if len(diff.FromDate) > 0 {
+				fromDate = "\t" + diff.FromDate
+			}
+			toDate := ""
+			if len(diff.ToDate) > 0 {
+				toDate = "\t" + diff.ToDate
+			}
+			w("*** %s%s%s", diff.FromFile, fromDate, diff.Eol)
+			w("--- %s%s%s", diff.ToFile, toDate, diff.Eol)
+		}
+
+		first, last := g[0], g[len(g)-1]
+		w("***************" + diff.Eol)
+
+		range1 := formatRangeContext(first.I1, last.I2)
+		w("*** %s ****%s", range1, diff.Eol)
+		for _, c := range g {
+			if c.Tag == 'r' || c.Tag == 'd' {
+				for _, cc := range g {
+					if cc.Tag == 'i' {
+						continue
+					}
+					for _, line := range diff.A[cc.I1:cc.I2] {
+						w(prefix[cc.Tag] + line)
+					}
+				}
+				break
+			}
+		}
+
+		range2 := formatRangeContext(first.J1, last.J2)
+		w("--- %s ----%s", range2, diff.Eol)
+		for _, c := range g {
+			if c.Tag == 'r' || c.Tag == 'i' {
+				for _, cc := range g {
+					if cc.Tag == 'd' {
+						continue
+					}
+					for _, line := range diff.B[cc.J1:cc.J2] {
+						w(prefix[cc.Tag] + line)
+					}
+				}
+				break
+			}
+		}
+	}
+	return diffErr
+}
+
+// Like WriteContextDiff but returns the diff a string.
+func GetContextDiffString(diff ContextDiff) (string, error) {
+	w := &bytes.Buffer{}
+	err := WriteContextDiff(w, diff)
+	return string(w.Bytes()), err
+}
+
+// Split a string on "\n" while preserving them. The output can be used
+// as input for UnifiedDiff and ContextDiff structures.
+func SplitLines(s string) []string {
+	lines := strings.SplitAfter(s, "\n")
+	lines[len(lines)-1] += "\n"
+	return lines
+}

vendor/github.com/pmezard/go-difflib/difflib/difflib_test.go

@@ -0,0 +1,352 @@
+package difflib
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func assertAlmostEqual(t *testing.T, a, b float64, places int) {
+	if math.Abs(a-b) > math.Pow10(-places) {
+		t.Errorf("%.7f != %.7f", a, b)
+	}
+}
+
+func assertEqual(t *testing.T, a, b interface{}) {
+	if !reflect.DeepEqual(a, b) {
+		t.Errorf("%v != %v", a, b)
+	}
+}
+
+func splitChars(s string) []string {
+	chars := make([]string, 0, len(s))
+	// Assume ASCII inputs
+	for i := 0; i != len(s); i++ {
+		chars = append(chars, string(s[i]))
+	}
+	return chars
+}
+
+func TestSequenceMatcherRatio(t *testing.T) {
+	s := NewMatcher(splitChars("abcd"), splitChars("bcde"))
+	assertEqual(t, s.Ratio(), 0.75)
+	assertEqual(t, s.QuickRatio(), 0.75)
+	assertEqual(t, s.RealQuickRatio(), 1.0)
+}
+
+func TestGetOptCodes(t *testing.T) {
+	a := "qabxcd"
+	b := "abycdf"
+	s := NewMatcher(splitChars(a), splitChars(b))
+	w := &bytes.Buffer{}
+	for _, op := range s.GetOpCodes() {
+		fmt.Fprintf(w, "%s a[%d:%d], (%s) b[%d:%d] (%s)\n", string(op.Tag),
+			op.I1, op.I2, a[op.I1:op.I2], op.J1, op.J2, b[op.J1:op.J2])
+	}
+	result := string(w.Bytes())
+	expected := `d a[0:1], (q) b[0:0] ()
+e a[1:3], (ab) b[0:2] (ab)
+r a[3:4], (x) b[2:3] (y)
+e a[4:6], (cd) b[3:5] (cd)
+i a[6:6], () b[5:6] (f)
+`
+	if expected != result {
+		t.Errorf("unexpected op codes: \n%s", result)
+	}
+}
+
+func TestGroupedOpCodes(t *testing.T) {
+	a := []string{}
+	for i := 0; i != 39; i++ {
+		a = append(a, fmt.Sprintf("%02d", i))
+	}
+	b := []string{}
+	b = append(b, a[:8]...)
+	b = append(b, " i")
+	b = append(b, a[8:19]...)
+	b = append(b, " x")
+	b = append(b, a[20:22]...)
+	b = append(b, a[27:34]...)
+	b = append(b, " y")
+	b = append(b, a[35:]...)
+	s := NewMatcher(a, b)
+	w := &bytes.Buffer{}
+	for _, g := range s.GetGroupedOpCodes(-1) {
+		fmt.Fprintf(w, "group\n")
+		for _, op := range g {
+			fmt.Fprintf(w, "  %s, %d, %d, %d, %d\n", string(op.Tag),
+				op.I1, op.I2, op.J1, op.J2)
+		}
+	}
+	result := string(w.Bytes())
+	expected := `group
+  e, 5, 8, 5, 8
+  i, 8, 8, 8, 9
+  e, 8, 11, 9, 12
+group
+  e, 16, 19, 17, 20
+  r, 19, 20, 20, 21
+  e, 20, 22, 21, 23
+  d, 22, 27, 23, 23
+  e, 27, 30, 23, 26
+group
+  e, 31, 34, 27, 30
+  r, 34, 35, 30, 31
+  e, 35, 38, 31, 34
+`
+	if expected != result {
+		t.Errorf("unexpected op codes: \n%s", result)
+	}
+}
+
+func ExampleGetUnifiedDiffString() {
+	a := `one
+two
+three
+four`
+	b := `zero
+one
+three
+four`
+	diff := UnifiedDiff{
+		A:        SplitLines(a),
+		B:        SplitLines(b),
+		FromFile: "Original",
+		FromDate: "2005-01-26 23:30:50",
+		ToFile:   "Current",
+		ToDate:   "2010-04-02 10:20:52",
+		Context:  3,
+	}
+	result, _ := GetUnifiedDiffString(diff)
+	fmt.Printf(strings.Replace(result, "\t", " ", -1))
+	// Output:
+	// --- Original 2005-01-26 23:30:50
+	// +++ Current 2010-04-02 10:20:52
+	// @@ -1,4 +1,4 @@
+	// +zero
+	//  one
+	// -two
+	//  three
+	//  four
+}
+
+func ExampleGetContextDiffString() {
+	a := `one
+two
+three
+four`
+	b := `zero
+one
+tree
+four`
+	diff := ContextDiff{
+		A:        SplitLines(a),
+		B:        SplitLines(b),
+		FromFile: "Original",
+		ToFile:   "Current",
+		Context:  3,
+		Eol:      "\n",
+	}
+	result, _ := GetContextDiffString(diff)
+	fmt.Printf(strings.Replace(result, "\t", " ", -1))
+	// Output:
+	// *** Original
+	// --- Current
+	// ***************
+	// *** 1,4 ****
+	//   one
+	// ! two
+	// ! three
+	//   four
+	// --- 1,4 ----
+	// + zero
+	//   one
+	// ! tree
+	//   four
+}
+
+func rep(s string, count int) string {
+	return strings.Repeat(s, count)
+}
+
+func TestWithAsciiOneInsert(t *testing.T) {
+	sm := NewMatcher(splitChars(rep("b", 100)),
+		splitChars("a"+rep("b", 100)))
+	assertAlmostEqual(t, sm.Ratio(), 0.995, 3)
+	assertEqual(t, sm.GetOpCodes(),
+		[]OpCode{{'i', 0, 0, 0, 1}, {'e', 0, 100, 1, 101}})
+	assertEqual(t, len(sm.bPopular), 0)
+
+	sm = NewMatcher(splitChars(rep("b", 100)),
+		splitChars(rep("b", 50)+"a"+rep("b", 50)))
+	assertAlmostEqual(t, sm.Ratio(), 0.995, 3)
+	assertEqual(t, sm.GetOpCodes(),
+		[]OpCode{{'e', 0, 50, 0, 50}, {'i', 50, 50, 50, 51}, {'e', 50, 100, 51, 101}})
+	assertEqual(t, len(sm.bPopular), 0)
+}
+
+func TestWithAsciiOnDelete(t *testing.T) {
+	sm := NewMatcher(splitChars(rep("a", 40)+"c"+rep("b", 40)),
+		splitChars(rep("a", 40)+rep("b", 40)))
+	assertAlmostEqual(t, sm.Ratio(), 0.994, 3)
+	assertEqual(t, sm.GetOpCodes(),
+		[]OpCode{{'e', 0, 40, 0, 40}, {'d', 40, 41, 40, 40}, {'e', 41, 81, 40, 80}})
+}
+
+func TestWithAsciiBJunk(t *testing.T) {
+	isJunk := func(s string) bool {
+		return s == " "
+	}
+	sm := NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
+		splitChars(rep("a", 44)+rep("b", 40)), true, isJunk)
+	assertEqual(t, sm.bJunk, map[string]struct{}{})
+
+	sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
+		splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
+	assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}})
+
+	isJunk = func(s string) bool {
+		return s == " " || s == "b"
+	}
+	sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
+		splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
+	assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}, "b": struct{}{}})
+}
+
+func TestSFBugsRatioForNullSeqn(t *testing.T) {
+	sm := NewMatcher(nil, nil)
+	assertEqual(t, sm.Ratio(), 1.0)
+	assertEqual(t, sm.QuickRatio(), 1.0)
+	assertEqual(t, sm.RealQuickRatio(), 1.0)
+}
+
+func TestSFBugsComparingEmptyLists(t *testing.T) {
+	groups := NewMatcher(nil, nil).GetGroupedOpCodes(-1)
+	assertEqual(t, len(groups), 0)
+	diff := UnifiedDiff{
+		FromFile: "Original",
+		ToFile:   "Current",
+		Context:  3,
+	}
+	result, err := GetUnifiedDiffString(diff)
+	assertEqual(t, err, nil)
+	assertEqual(t, result, "")
+}
+
+func TestOutputFormatRangeFormatUnified(t *testing.T) {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	//
+	// Each <range> field shall be of the form:
+	//   %1d", <beginning line number>  if the range contains exactly one line,
+	// and:
+	//  "%1d,%1d", <beginning line number>, <number of lines> otherwise.
+	// If a range is empty, its beginning line number shall be the number of
+	// the line just before the range, or 0 if the empty range starts the file.
+	fm := formatRangeUnified
+	assertEqual(t, fm(3, 3), "3,0")
+	assertEqual(t, fm(3, 4), "4")
+	assertEqual(t, fm(3, 5), "4,2")
+	assertEqual(t, fm(3, 6), "4,3")
+	assertEqual(t, fm(0, 0), "0,0")
+}
+
+func TestOutputFormatRangeFormatContext(t *testing.T) {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	//
+	// The range of lines in file1 shall be written in the following format
+	// if the range contains two or more lines:
+	//     "*** %d,%d ****\n", <beginning line number>, <ending line number>
+	// and the following format otherwise:
+	//     "*** %d ****\n", <ending line number>
+	// The ending line number of an empty range shall be the number of the preceding line,
+	// or 0 if the range is at the start of the file.
+	//
+	// Next, the range of lines in file2 shall be written in the following format
+	// if the range contains two or more lines:
+	//     "--- %d,%d ----\n", <beginning line number>, <ending line number>
+	// and the following format otherwise:
+	//     "--- %d ----\n", <ending line number>
+	fm := formatRangeContext
+	assertEqual(t, fm(3, 3), "3")
+	assertEqual(t, fm(3, 4), "4")
+	assertEqual(t, fm(3, 5), "4,5")
+	assertEqual(t, fm(3, 6), "4,6")
+	assertEqual(t, fm(0, 0), "0")
+}
+
+func TestOutputFormatTabDelimiter(t *testing.T) {
+	diff := UnifiedDiff{
+		A:        splitChars("one"),
+		B:        splitChars("two"),
+		FromFile: "Original",
+		FromDate: "2005-01-26 23:30:50",
+		ToFile:   "Current",
+		ToDate:   "2010-04-12 10:20:52",
+		Eol:      "\n",
+	}
+	ud, err := GetUnifiedDiffString(diff)
+	assertEqual(t, err, nil)
+	assertEqual(t, SplitLines(ud)[:2], []string{
+		"--- Original\t2005-01-26 23:30:50\n",
+		"+++ Current\t2010-04-12 10:20:52\n",
+	})
+	cd, err := GetContextDiffString(ContextDiff(diff))
+	assertEqual(t, err, nil)
+	assertEqual(t, SplitLines(cd)[:2], []string{
+		"*** Original\t2005-01-26 23:30:50\n",
+		"--- Current\t2010-04-12 10:20:52\n",
+	})
+}
+
+func TestOutputFormatNoTrailingTabOnEmptyFiledate(t *testing.T) {
+	diff := UnifiedDiff{
+		A:        splitChars("one"),
+		B:        splitChars("two"),
+		FromFile: "Original",
+		ToFile:   "Current",
+		Eol:      "\n",
+	}
+	ud, err := GetUnifiedDiffString(diff)
+	assertEqual(t, err, nil)
+	assertEqual(t, SplitLines(ud)[:2], []string{"--- Original\n", "+++ Current\n"})
+
+	cd, err := GetContextDiffString(ContextDiff(diff))
+	assertEqual(t, err, nil)
+	assertEqual(t, SplitLines(cd)[:2], []string{"*** Original\n", "--- Current\n"})
+}
+
+func TestSplitLines(t *testing.T) {
+	allTests := []struct {
+		input string
+		want  []string
+	}{
+		{"foo", []string{"foo\n"}},
+		{"foo\nbar", []string{"foo\n", "bar\n"}},
+		{"foo\nbar\n", []string{"foo\n", "bar\n", "\n"}},
+	}
+	for _, test := range allTests {
+		assertEqual(t, SplitLines(test.input), test.want)
+	}
+}
+
+func benchmarkSplitLines(b *testing.B, count int) {
+	str := strings.Repeat("foo\n", count)
+
+	b.ResetTimer()
+
+	n := 0
+	for i := 0; i < b.N; i++ {
+		n += len(SplitLines(str))
+	}
+}
+
+func BenchmarkSplitLines100(b *testing.B) {
+	benchmarkSplitLines(b, 100)
+}
+
+func BenchmarkSplitLines10000(b *testing.B) {
+	benchmarkSplitLines(b, 10000)
+}

vendor/manifest

@@ -530,6 +530,12 @@
 			"revision": "1c83b3eabd45b6d76072b66b746c20815fb2872d",
 			"branch": "master"
 		},
+		{
+			"importpath": "github.com/gorilla/handlers",
+			"repository": "https://github.com/gorilla/handlers",
+			"revision": "9a8d6fa6e6479b56ec164996e54fa5d7eb3ef544",
+			"branch": "master"
+		},
 		{
 			"importpath": "github.com/gorilla/mux",
 			"repository": "https://github.com/gorilla/mux",
@@ -579,6 +585,13 @@
 			"revision": "cccd189d45f7ac3368a0d127efb7f4d08ae0b655",
 			"branch": "master"
 		},
+		{
+			"importpath": "github.com/pmezard/go-difflib/difflib",
+			"repository": "https://github.com/pmezard/go-difflib",
+			"revision": "f78a839676152fd9f4863704f5d516195c18fc14",
+			"branch": "master",
+			"path": "/difflib"
+		},
 		{
 			"importpath": "github.com/prometheus/client_golang/prometheus",
 			"repository": "https://github.com/prometheus/client_golang",