dashboard: fix a bug that could not handle proxy requests correctly (t…

…ikv#5326)

Signed-off-by: HunDunDM <hundundm@gmail.com>

pkg/dashboard/adapter/redirector.go

@@ -76,7 +76,7 @@ func (h *Redirector) SetAddress(addr string) {
 	defaultDirector := h.proxy.Director
 	h.proxy.Director = func(r *http.Request) {
 		defaultDirector(r)
-		r.Header.Set(proxyHeader, h.name)
+		r.Header.Add(proxyHeader, h.name)
 	}
 
 	if h.tlsConfig != nil {
@@ -118,9 +118,12 @@ func (h *Redirector) ReverseProxy(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if len(r.Header.Get(proxyHeader)) > 0 {
-		w.WriteHeader(http.StatusLoopDetected)
-		return
+	proxySources := r.Header.Values(proxyHeader)
+	for _, proxySource := range proxySources {
+		if proxySource == h.name {
+			w.WriteHeader(http.StatusLoopDetected)
+			return
+		}
 	}
 
 	proxy.ServeHTTP(w, r)

pkg/dashboard/adapter/redirector_test.go

@@ -0,0 +1,111 @@
+// Copyright 2022 TiKV Project Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	. "github.com/pingcap/check"
+)
+
+func TestDashboardAdapter(t *testing.T) {
+	TestingT(t)
+}
+
+var _ = Suite(&testRedirectorSuite{})
+
+type testRedirectorSuite struct {
+	tempText   string
+	tempServer *httptest.Server
+
+	testName   string
+	redirector *Redirector
+
+	noRedirectHTTPClient *http.Client
+}
+
+func (s *testRedirectorSuite) SetUpSuite(c *C) {
+	s.tempText = "temp1"
+	s.tempServer = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = io.WriteString(w, s.tempText)
+	}))
+
+	s.testName = "test1"
+	s.redirector = NewRedirector(s.testName, nil)
+	s.noRedirectHTTPClient = &http.Client{
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			// ErrUseLastResponse can be returned by Client.CheckRedirect hooks to
+			// control how redirects are processed. If returned, the next request
+			// is not sent and the most recent response is returned with its body
+			// unclosed.
+			return http.ErrUseLastResponse
+		},
+	}
+}
+
+func (s *testRedirectorSuite) TearDownSuite(c *C) {
+	s.tempServer.Close()
+	s.noRedirectHTTPClient.CloseIdleConnections()
+}
+
+func (s *testRedirectorSuite) TestReverseProxy(c *C) {
+	redirectorServer := httptest.NewServer(http.HandlerFunc(s.redirector.ReverseProxy))
+	defer redirectorServer.Close()
+
+	s.redirector.SetAddress(s.tempServer.URL)
+	// Test normal forwarding
+	req, err := http.NewRequest(http.MethodGet, redirectorServer.URL, nil)
+	c.Assert(err, IsNil)
+	checkHTTPRequest(c, s.noRedirectHTTPClient, req, http.StatusOK, s.tempText)
+	// Test the requests that are forwarded by others
+	req, err = http.NewRequest(http.MethodGet, redirectorServer.URL, nil)
+	c.Assert(err, IsNil)
+	req.Header.Set(proxyHeader, "other")
+	checkHTTPRequest(c, s.noRedirectHTTPClient, req, http.StatusOK, s.tempText)
+	// Test LoopDetected
+	s.redirector.SetAddress(redirectorServer.URL)
+	req, err = http.NewRequest(http.MethodGet, redirectorServer.URL, nil)
+	c.Assert(err, IsNil)
+	checkHTTPRequest(c, s.noRedirectHTTPClient, req, http.StatusLoopDetected, "")
+}
+
+func (s *testRedirectorSuite) TestTemporaryRedirect(c *C) {
+	redirectorServer := httptest.NewServer(http.HandlerFunc(s.redirector.TemporaryRedirect))
+	defer redirectorServer.Close()
+	s.redirector.SetAddress(s.tempServer.URL)
+	// Test TemporaryRedirect
+	req, err := http.NewRequest(http.MethodGet, redirectorServer.URL, nil)
+	c.Assert(err, IsNil)
+	checkHTTPRequest(c, s.noRedirectHTTPClient, req, http.StatusTemporaryRedirect, "")
+	// Test Response
+	req, err = http.NewRequest(http.MethodGet, redirectorServer.URL, nil)
+	c.Assert(err, IsNil)
+	checkHTTPRequest(c, http.DefaultClient, req, http.StatusOK, s.tempText)
+}
+
+func checkHTTPRequest(c *C, client *http.Client, req *http.Request, expectedCode int, expectedText string) {
+	resp, err := client.Do(req)
+	c.Assert(err, IsNil)
+	defer resp.Body.Close()
+	c.Assert(resp.StatusCode, Equals, expectedCode)
+	if expectedCode >= http.StatusOK && expectedCode <= http.StatusAlreadyReported {
+		text, err := io.ReadAll(resp.Body)
+		c.Assert(err, IsNil)
+		c.Assert(string(text), Equals, expectedText)
+	}
+}