Rework Host and HostRegexp matchers

Co-authored-by: Simon Delicata <simon.delicata@traefik.io>

docs/content/routing/routers/index.md

@@ -288,6 +288,8 @@ These matchers do not support non-ASCII characters, use punycode encoded values
 
 If no Host is set in the request URL (e.g., it's an IP address), these matchers will look at the `Host` header.
 
+These matchers will match the request's host in lowercase.
+
 !!! example "Examples"
 
     Match requests with `Host` set to `example.com`:

pkg/muxer/http/matcher.go

@@ -75,25 +75,6 @@ func host(route *mux.Route, hosts ...string) error {
 	route.MatcherFunc(func(req *http.Request, _ *mux.RouteMatch) bool {
 		reqHost := requestdecorator.GetCanonizedHost(req.Context())
 		if len(reqHost) == 0 {
-			// If the request is an HTTP/1.0 request, then a Host may not be defined.
-			if req.ProtoAtLeast(1, 1) {
-				log.Ctx(req.Context()).Warn().Str("host", req.Host).Msg("Could not retrieve CanonizedHost, rejecting")
-			}
-
-			return false
-		}
-
-		flatH := requestdecorator.GetCNAMEFlatten(req.Context())
-		if len(flatH) > 0 {
-			if strings.EqualFold(reqHost, host) || strings.EqualFold(flatH, host) {
-				return true
-			}
-
-			log.Ctx(req.Context()).Debug().
-				Str("host", reqHost).
-				Str("flattenHost", flatH).
-				Str("matcher", host).
-				Msg("CNAMEFlattening: resolved Host does not match")
 			return false
 		}
 
@@ -101,6 +82,11 @@ func host(route *mux.Route, hosts ...string) error {
 			return true
 		}
 
+		flatH := requestdecorator.GetCNAMEFlatten(req.Context())
+		if len(flatH) > 0 {
+			return strings.EqualFold(flatH, host)
+		}
+
 		// Check for match on trailing period on host
 		if last := len(host) - 1; last >= 0 && host[last] == '.' {
 			h := host[:last]
@@ -136,7 +122,8 @@ func hostRegexp(route *mux.Route, hosts ...string) error {
 	}
 
 	route.MatcherFunc(func(req *http.Request, _ *mux.RouteMatch) bool {
-		return re.MatchString(req.Host)
+		return re.MatchString(requestdecorator.GetCanonizedHost(req.Context())) ||
+			re.MatchString(requestdecorator.GetCNAMEFlatten(req.Context()))
 	})
 
 	return nil

pkg/muxer/http/matcher_test.go

@@ -198,6 +198,7 @@ func TestHostMatcher(t *testing.T) {
 			rule: "Host(`example.com`)",
 			expected: map[string]int{
 				"https://example.com":      http.StatusOK,
+				"https://example.com:8080": http.StatusOK,
 				"https://example.com/path": http.StatusOK,
 				"https://example.org":      http.StatusNotFound,
 				"https://example.org/path": http.StatusNotFound,
@@ -227,6 +228,16 @@ func TestHostMatcher(t *testing.T) {
 				"https://example.org./path": http.StatusNotFound,
 			},
 		},
+		{
+			desc: "valid Host matcher - matcher with UPPER case",
+			rule: "Host(`EXAMPLE.COM`)",
+			expected: map[string]int{
+				"https://example.com":      http.StatusOK,
+				"https://example.com/path": http.StatusOK,
+				"https://example.org":      http.StatusNotFound,
+				"https://example.org/path": http.StatusNotFound,
+			},
+		},
 		{
 			desc: "valid Host matcher - puny-coded emoji",
 			rule: "Host(`xn--9t9h.com`)",
@@ -258,7 +269,7 @@ func TestHostMatcher(t *testing.T) {
 
 			require.NoError(t, err)
 
-			// RequestDecorator is necessary for the host rule
+			// RequestDecorator is necessary for the Host matcher
 			reqHost := requestdecorator.New(nil)
 
 			results := make(map[string]int)
@@ -312,11 +323,23 @@ func TestHostRegexpMatcher(t *testing.T) {
 			rule: "HostRegexp(`^[a-zA-Z-]+\\.com$`)",
 			expected: map[string]int{
 				"https://example.com":      http.StatusOK,
+				"https://example.com:8080": http.StatusOK,
 				"https://example.com/path": http.StatusOK,
 				"https://example.org":      http.StatusNotFound,
 				"https://example.org/path": http.StatusNotFound,
 			},
 		},
+		{
+			desc: "valid HostRegexp matcher with case sensitive regexp",
+			rule: "HostRegexp(`^[A-Z]+\\.com$`)",
+			expected: map[string]int{
+				"https://example.com":      http.StatusNotFound,
+				"https://EXAMPLE.com":      http.StatusNotFound,
+				"https://example.com/path": http.StatusNotFound,
+				"https://example.org":      http.StatusNotFound,
+				"https://example.org/path": http.StatusNotFound,
+			},
+		},
 		{
 			desc: "valid HostRegexp matcher with Traefik v2 syntax",
 			rule: "HostRegexp(`{domain:[a-zA-Z-]+\\.com}`)",
@@ -343,16 +366,18 @@ func TestHostRegexpMatcher(t *testing.T) {
 				require.Error(t, err)
 				return
 			}
-
 			require.NoError(t, err)
 
+			// RequestDecorator is necessary for the HostRegexp matcher
+			reqHost := requestdecorator.New(nil)
+
 			results := make(map[string]int)
 			for calledURL := range test.expected {
 				w := httptest.NewRecorder()
 
 				req := httptest.NewRequest(http.MethodGet, calledURL, http.NoBody)
 
-				muxer.ServeHTTP(w, req)
+				reqHost.ServeHTTP(w, req, muxer.ServeHTTP)
 				results[calledURL] = w.Code
 			}
 			assert.Equal(t, test.expected, results)