From 264e5b7911a7741a01e14c8bc473df253f639309 Mon Sep 17 00:00:00 2001
From: Nimi Wariboko Jr <nimi@channelmeter.com>
Date: Sun, 3 May 2015 13:33:08 -0700
Subject: Use the provided Replacer tools in order to proxy string
 interpolation.

---
 middleware/proxy/proxy.go | 78 +++++++++--------------------------------------
 1 file changed, 14 insertions(+), 64 deletions(-)

diff --git a/middleware/proxy/proxy.go b/middleware/proxy/proxy.go
index cc3b068da..083c27054 100644
--- a/middleware/proxy/proxy.go
+++ b/middleware/proxy/proxy.go
@@ -4,11 +4,8 @@ package proxy
 import (
 	"errors"
 	"github.com/mholt/caddy/middleware"
-	"net"
 	"net/http"
 	"net/url"
-	"regexp"
-	"strings"
 	"sync/atomic"
 	"time"
 )
@@ -34,6 +31,7 @@ type UpstreamHostDownFunc func(*UpstreamHost) bool
 
 // An UpstreamHost represents a single proxy upstream
 type UpstreamHost struct {
+	// The hostname of this upstream host
 	Name         string
 	ReverseProxy *ReverseProxy
 	Conns        int64
@@ -52,81 +50,27 @@ func (uh *UpstreamHost) Down() bool {
 	return uh.CheckDown(uh)
 }
 
-//https://github.com/mgutz/str
-var tRe = regexp.MustCompile(`([\-\[\]()*\s])`)
-var tRe2 = regexp.MustCompile(`\$`)
-var openDelim = tRe2.ReplaceAllString(tRe.ReplaceAllString("{{", "\\$1"), "\\$")
-var closDelim = tRe2.ReplaceAllString(tRe.ReplaceAllString("}}", "\\$1"), "\\$")
-var templateDelim = regexp.MustCompile(openDelim + `(.+?)` + closDelim)
-
-type requestVars struct {
-	Host         string
-	RemoteIp     string
-	Scheme       string
-	Upstream     string
-	UpstreamHost string
-}
-
-func templateWithDelimiters(s string, vars requestVars) string {
-	matches := templateDelim.FindAllStringSubmatch(s, -1)
-	for _, submatches := range matches {
-		match := submatches[0]
-		key := submatches[1]
-		found := true
-		repl := ""
-		switch key {
-		case "http_host":
-			repl = vars.Host
-		case "remote_addr":
-			repl = vars.RemoteIp
-		case "scheme":
-			repl = vars.Scheme
-		case "upstream":
-			repl = vars.Upstream
-		case "upstream_host":
-			repl = vars.UpstreamHost
-		default:
-			found = false
-		}
-		if found {
-			s = strings.Replace(s, match, repl, -1)
-		}
-	}
-	return s
-}
-
 // ServeHTTP satisfies the middleware.Handler interface.
 func (p Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 
 	for _, upstream := range p.Upstreams {
 		if middleware.Path(r.URL.Path).Matches(upstream.From()) {
-			vars := requestVars{
-				Host:   r.Host,
-				Scheme: "http",
-			}
-			if clientIP, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
-				vars.RemoteIp = clientIP
-			}
-			if fFor := r.Header.Get("X-Forwarded-For"); fFor != "" {
-				vars.RemoteIp = fFor
-			}
-			if r.TLS != nil {
-				vars.Scheme = "https"
-			}
+			var replacer middleware.Replacer
+			start := time.Now()
+			requestHost := r.Host
+
 			// Since Select() should give us "up" hosts, keep retrying
 			// hosts until timeout (or until we get a nil host).
-			start := time.Now()
 			for time.Now().Sub(start) < (60 * time.Second) {
 				host := upstream.Select()
 				if host == nil {
 					return http.StatusBadGateway, errUnreachable
 				}
 				proxy := host.ReverseProxy
-				vars.Upstream = host.Name
 				r.Host = host.Name
 
 				if baseUrl, err := url.Parse(host.Name); err == nil {
-					vars.UpstreamHost = baseUrl.Host
+					r.Host = baseUrl.Host
 					if proxy == nil {
 						proxy = NewSingleHostReverseProxy(baseUrl)
 					}
@@ -136,12 +80,18 @@ func (p Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 				var extraHeaders http.Header
 				if host.ExtraHeaders != nil {
 					extraHeaders = make(http.Header)
+					if replacer == nil {
+						rHost := r.Host
+						r.Host = requestHost
+						replacer = middleware.NewReplacer(r, nil)
+						r.Host = rHost
+					}
 					for header, values := range host.ExtraHeaders {
 						for _, value := range values {
 							extraHeaders.Add(header,
-								templateWithDelimiters(value, vars))
+								replacer.Replace(value))
 							if header == "Host" {
-								r.Host = templateWithDelimiters(value, vars)
+								r.Host = replacer.Replace(value)
 							}
 						}
 					}
-- 
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