From 4baca884c5e4767b114f3d363188e6570a24e90d Mon Sep 17 00:00:00 2001
From: Tw <tw19881113@gmail.com>
Date: Tue, 11 Oct 2016 17:06:49 +0800
Subject: [PATCH] proxy: preserve path trailing slash if it was there

fix issue #1177

Signed-off-by: Tw <tw19881113@gmail.com>
---
 caddyhttp/proxy/proxy_test.go   | 5 +++++
 caddyhttp/proxy/reverseproxy.go | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/caddyhttp/proxy/proxy_test.go b/caddyhttp/proxy/proxy_test.go
index be55ff566..ccdb068bb 100644
--- a/caddyhttp/proxy/proxy_test.go
+++ b/caddyhttp/proxy/proxy_test.go
@@ -791,6 +791,11 @@ func TestProxyDirectorURL(t *testing.T) {
 			expectURL:  `https://localhost:2021/t?foo%3dbar&t%3dw`,
 			without:    "/test",
 		},
+		{
+			requestURL: `http://localhost:2020/test/`,
+			targetURL:  `https://localhost:2021/t/`,
+			expectURL:  `https://localhost:2021/t/test/`,
+		},
 	} {
 		targetURL, err := url.Parse(c.targetURL)
 		if err != nil {
diff --git a/caddyhttp/proxy/reverseproxy.go b/caddyhttp/proxy/reverseproxy.go
index 1374c08ff..c537f7c98 100644
--- a/caddyhttp/proxy/reverseproxy.go
+++ b/caddyhttp/proxy/reverseproxy.go
@@ -96,7 +96,13 @@ func NewSingleHostReverseProxy(target *url.URL, without string, keepalive int) *
 			}
 		}
 
+		hadTrailingSlash := strings.HasSuffix(req.URL.Path, "/")
 		req.URL.Path = path.Join(target.Path, req.URL.Path)
+		// path.Join will strip off the last /, so put it back if it was there.
+		if hadTrailingSlash && !strings.HasSuffix(req.URL.Path, "/") {
+			req.URL.Path = req.URL.Path + "/"
+		}
+
 		// Trims the path of the socket from the URL path.
 		// This is done because req.URL passed to your proxied service
 		// will have the full path of the socket file prefixed to it.