From b7bb23720f64c9f4256622d5a6927c6f7f6cb25c Mon Sep 17 00:00:00 2001
From: Tim Raymond <tim@timraymond.com>
Date: Tue, 9 May 2017 12:05:10 -0700
Subject: [PATCH 1/2] Fix infinite spinner with /chronograf basepath

When using a basepath of /chronograf, the app would present a
never-ending spinner when visiting the root route. This was because the
prefixingRedirector middleware which is responsible for appending the
basepath to redirects from downstream http.Handlers thought that the
prefix was already appended since it saw `/chronograf/v1`. In reality,
it should have produced a location like `/chronograf/chronograf/v1`.

The solution was to look beyond the first instance of a prefix and check
for the presence of another prefix to detect if a prefix was already
applied by a downstream handler.
---
 server/prefixing_redirector.go      |  3 +-
 server/prefixing_redirector_test.go | 87 +++++++++++++++++++++++++++++
 2 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 server/prefixing_redirector_test.go

diff --git a/server/prefixing_redirector.go b/server/prefixing_redirector.go
index eec4e9fd7..86f957efa 100644
--- a/server/prefixing_redirector.go
+++ b/server/prefixing_redirector.go
@@ -16,7 +16,8 @@ func (i *interceptingResponseWriter) WriteHeader(status int) {
 	if status >= 300 && status < 400 {
 		location := i.ResponseWriter.Header().Get("Location")
 		if u, err := url.Parse(location); err == nil && !u.IsAbs() {
-			if !strings.HasPrefix(location, i.Prefix) {
+			hasPrefix := strings.HasPrefix(u.Path, i.Prefix)
+			if !hasPrefix || (hasPrefix && !strings.HasPrefix(u.Path[len(i.Prefix):], i.Prefix)) {
 				i.ResponseWriter.Header().Set("Location", path.Join(i.Prefix, location)+"/")
 			}
 		}
diff --git a/server/prefixing_redirector_test.go b/server/prefixing_redirector_test.go
new file mode 100644
index 000000000..728c90604
--- /dev/null
+++ b/server/prefixing_redirector_test.go
@@ -0,0 +1,87 @@
+package server
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+var prefixingRedirectTests = []struct {
+	CaseName       string
+	RedirectTarget string
+	Prefix         string
+	Expected       string
+}{
+	{
+		"ChronografBasepath",
+		"/chronograf/v1/",
+		"/chronograf",
+		"/chronograf/chronograf/v1/",
+	},
+	{
+		"DifferentBasepath",
+		"/chronograf/v1/",
+		"/delorean",
+		"/delorean/chronograf/v1/",
+	},
+	{
+		"TrailingSlashPrefix",
+		"/chronograf/v1/",
+		"/delorean/",
+		"/delorean/chronograf/v1/",
+	},
+	{
+		"NoPrefix",
+		"/chronograf/v1/",
+		"",
+		"/chronograf/v1/",
+	},
+	{
+		"SlashPrefix",
+		"/chronograf/v1/",
+		"/",
+		"/chronograf/v1/",
+	},
+	{
+		"AlreadyPrefixed",
+		"/chronograf/chronograf/v1/",
+		"/chronograf",
+		"/chronograf/chronograf/v1/",
+	},
+}
+
+func Test_PrefixingRedirector(t *testing.T) {
+	t.Parallel()
+	for _, p := range prefixingRedirectTests {
+		t.Run(p.CaseName, func(subt *testing.T) {
+			hf := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+				rw.Header().Set("Location", p.RedirectTarget)
+				rw.WriteHeader(http.StatusTemporaryRedirect)
+			})
+			pr := PrefixedRedirect(p.Prefix, hf)
+
+			ts := httptest.NewServer(pr)
+			defer ts.Close()
+
+			hc := http.Client{
+				CheckRedirect: func(req *http.Request, via []*http.Request) error {
+					return http.ErrUseLastResponse
+				},
+			}
+
+			mockBody := strings.NewReader("")
+			req, _ := http.NewRequest("GET", ts.URL, mockBody)
+
+			resp, err := hc.Do(req)
+			if err != nil {
+				subt.Fatal("Unexpected http err:", err)
+			}
+
+			expected := p.Expected
+			if loc := resp.Header.Get("Location"); loc != expected {
+				subt.Fatal("Unexpected redirected location. Expected:", expected, "Actual:", loc)
+			}
+		})
+	}
+}

From 8cae369cb629bbe59ce29ae6769754975d67691c Mon Sep 17 00:00:00 2001
From: Tim Raymond <tim@timraymond.com>
Date: Tue, 9 May 2017 12:24:43 -0700
Subject: [PATCH 2/2] Update CHANGELOG for infinite spinner basepath fix

---
 CHANGELOG.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index aec821865..4bcc1af78 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+## v1.3.1 [unreleased]
+
+### Bug Fixes
+  1. [#1450](https://github.com/influxdata/chronograf/pull/1450): Fix infinite spinner when using "/chronograf" as a basepath
+
+### Features
+
+### UI Improvements
+
 ## v1.3.0 [2017-05-09]
 
 ### Bug Fixes