Merge pull request #128925 from richabanker/zpages-cleanup

Move zpages common code to an httputil package

staging/src/k8s.io/component-base/zpages/flagz/flagz.go

@@ -23,11 +23,9 @@ import (
 	"math/rand"
 	"net/http"
 	"sort"
-	"strings"
 	"sync"
 
-	"github.com/munnerz/goautoneg"
+	"k8s.io/component-base/zpages/httputil"
-
 	"k8s.io/klog/v2"
 )
 
@@ -40,8 +38,7 @@ Warning: This endpoint is not meant to be machine parseable, has no formatting c
 )
 
 var (
-	flagzSeparators         = []string{":", ": ", "=", " "}
+	delimiters = []string{":", ": ", "=", " "}
-	errUnsupportedMediaType = fmt.Errorf("media type not acceptable, must be: text/plain")
 )
 
 type registry struct {
@@ -64,8 +61,8 @@ func (reg *registry) installHandler(m mux, componentName string, flagReader Read
 
 func (reg *registry) handleFlags(componentName string, flagReader Reader) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		if !acceptableMediaType(r) {
+		if !httputil.AcceptableMediaType(r) {
-			http.Error(w, errUnsupportedMediaType.Error(), http.StatusNotAcceptable)
+			http.Error(w, httputil.ErrUnsupportedMediaType.Error(), http.StatusNotAcceptable)
 			return
 		}
 
@@ -76,8 +73,8 @@ func (reg *registry) handleFlags(componentName string, flagReader Reader) http.H
 				return
 			}
 
-			randomIndex := rand.Intn(len(flagzSeparators))
+			randomIndex := rand.Intn(len(delimiters))
-			separator := flagzSeparators[randomIndex]
+			separator := delimiters[randomIndex]
 			// Randomize the delimiter for printing to prevent scraping of the response.
 			printSortedFlags(&reg.response, flagReader.GetFlagz(), separator)
 		})
@@ -90,29 +87,6 @@ func (reg *registry) handleFlags(componentName string, flagReader Reader) http.H
 	}
 }
 
-func acceptableMediaType(r *http.Request) bool {
-	accepts := goautoneg.ParseAccept(r.Header.Get("Accept"))
-	for _, accept := range accepts {
-		if !mediaTypeMatches(accept) {
-			continue
-		}
-		if len(accept.Params) == 0 {
-			return true
-		}
-		if len(accept.Params) == 1 {
-			if charset, ok := accept.Params["charset"]; ok && strings.EqualFold(charset, "utf-8") {
-				return true
-			}
-		}
-	}
-	return false
-}
-
-func mediaTypeMatches(a goautoneg.Accept) bool {
-	return (a.Type == "text" || a.Type == "*") &&
-		(a.SubType == "plain" || a.SubType == "*")
-}
-
 func printSortedFlags(w io.Writer, flags map[string]string, separator string) {
 	var sortedKeys []string
 	for key := range flags {

staging/src/k8s.io/component-base/zpages/flagz/flagz_test.go

@@ -35,7 +35,7 @@ Warning: This endpoint is not meant to be machine parseable, has no formatting c
 
 func TestFlagz(t *testing.T) {
 	componentName := "test-server"
-	flagzSeparators = []string{"="}
+	delimiters = []string{"="}
 	wantHeaderLines := strings.Split(fmt.Sprintf(wantTmpl, componentName), "\n")
 	tests := []struct {
 		name        string

staging/src/k8s.io/component-base/zpages/httputil/httputil.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2024 The Kubernetes 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 httputil
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/munnerz/goautoneg"
+)
+
+// ErrUnsupportedMediaType is the error returned when the request's
+// Accept header does not contain "text/plain".
+var ErrUnsupportedMediaType = fmt.Errorf("media type not acceptable, must be: text/plain")
+
+// AcceptableMediaType checks if the request's Accept header contains
+// a supported media type with optional "charset=utf-8" parameter.
+func AcceptableMediaType(r *http.Request) bool {
+	accepts := goautoneg.ParseAccept(r.Header.Get("Accept"))
+	for _, accept := range accepts {
+		if !mediaTypeMatches(accept) {
+			continue
+		}
+		if len(accept.Params) == 0 {
+			return true
+		}
+		if len(accept.Params) == 1 {
+			if charset, ok := accept.Params["charset"]; ok && strings.EqualFold(charset, "utf-8") {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func mediaTypeMatches(a goautoneg.Accept) bool {
+	return (a.Type == "text" || a.Type == "*") &&
+		(a.SubType == "plain" || a.SubType == "*")
+}

staging/src/k8s.io/component-base/zpages/httputil/httputil_test.go

@@ -0,0 +1,74 @@
+/*
+Copyright 2024 The Kubernetes 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 httputil
+
+import (
+	"net/http"
+	"testing"
+)
+
+func TestAcceptableMediaTypes(t *testing.T) {
+	tests := []struct {
+		name      string
+		reqHeader string
+		want      bool
+	}{
+		{
+			name:      "valid text/plain header",
+			reqHeader: "text/plain",
+			want:      true,
+		},
+		{
+			name:      "valid text/* header",
+			reqHeader: "text/*",
+			want:      true,
+		},
+		{
+			name:      "valid */plain header",
+			reqHeader: "*/plain",
+			want:      true,
+		},
+		{
+			name:      "valid accept args",
+			reqHeader: "text/plain; charset=utf-8",
+			want:      true,
+		},
+		{
+			name:      "invalid text/foo header",
+			reqHeader: "text/foo",
+			want:      false,
+		},
+		{
+			name:      "invalid text/plain params",
+			reqHeader: "text/plain; foo=bar",
+			want:      false,
+		},
+	}
+	for _, tt := range tests {
+		req, err := http.NewRequest(http.MethodGet, "http://example.com/statusz", nil)
+		if err != nil {
+			t.Fatalf("Unexpected error while creating request: %v", err)
+		}
+
+		req.Header.Set("Accept", tt.reqHeader)
+		got := AcceptableMediaType(req)
+
+		if got != tt.want {
+			t.Errorf("Unexpected response from AcceptableMediaType(), want %v, got = %v", tt.want, got)
+		}
+	}
+}

staging/src/k8s.io/component-base/zpages/statusz/statusz.go

@@ -22,17 +22,14 @@ import (
 	"html/template"
 	"math/rand"
 	"net/http"
-	"strings"
 	"time"
 
-	"github.com/munnerz/goautoneg"
+	"k8s.io/component-base/zpages/httputil"
-
 	"k8s.io/klog/v2"
 )
 
 var (
-	delimiters              = []string{":", ": ", "=", " "}
+	delimiters = []string{":", ": ", "=", " "}
-	errUnsupportedMediaType = fmt.Errorf("media type not acceptable, must be: text/plain")
 )
 
 const DefaultStatuszPath = "/statusz"
@@ -90,8 +87,8 @@ func initializeTemplates() (*template.Template, error) {
 
 func handleStatusz(componentName string, dataTmpl *template.Template, reg statuszRegistry) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		if !acceptableMediaType(r) {
+		if !httputil.AcceptableMediaType(r) {
-			http.Error(w, errUnsupportedMediaType.Error(), http.StatusNotAcceptable)
+			http.Error(w, httputil.ErrUnsupportedMediaType.Error(), http.StatusNotAcceptable)
 			return
 		}
 
@@ -108,30 +105,6 @@ func handleStatusz(componentName string, dataTmpl *template.Template, reg status
 	}
 }
 
-// TODO(richabanker) : Move this to a common place to be reused for all zpages.
-func acceptableMediaType(r *http.Request) bool {
-	accepts := goautoneg.ParseAccept(r.Header.Get("Accept"))
-	for _, accept := range accepts {
-		if !mediaTypeMatches(accept) {
-			continue
-		}
-		if len(accept.Params) == 0 {
-			return true
-		}
-		if len(accept.Params) == 1 {
-			if charset, ok := accept.Params["charset"]; ok && strings.EqualFold(charset, "utf-8") {
-				return true
-			}
-		}
-	}
-	return false
-}
-
-func mediaTypeMatches(a goautoneg.Accept) bool {
-	return (a.Type == "text" || a.Type == "*") &&
-		(a.SubType == "plain" || a.SubType == "*")
-}
-
 func populateStatuszData(tmpl *template.Template, reg statuszRegistry) (string, error) {
 	if tmpl == nil {
 		return "", fmt.Errorf("received nil template")

staging/src/k8s.io/component-base/zpages/statusz/statusz_test.go

@@ -152,58 +152,6 @@ func TestStatusz(t *testing.T) {
 	}
 }
 
-func TestAcceptableMediaTypes(t *testing.T) {
-	tests := []struct {
-		name      string
-		reqHeader string
-		want      bool
-	}{
-		{
-			name:      "valid text/plain header",
-			reqHeader: "text/plain",
-			want:      true,
-		},
-		{
-			name:      "valid text/* header",
-			reqHeader: "text/*",
-			want:      true,
-		},
-		{
-			name:      "valid */plain header",
-			reqHeader: "*/plain",
-			want:      true,
-		},
-		{
-			name:      "valid accept args",
-			reqHeader: "text/plain; charset=utf-8",
-			want:      true,
-		},
-		{
-			name:      "invalid text/foo header",
-			reqHeader: "text/foo",
-			want:      false,
-		},
-		{
-			name:      "invalid text/plain params",
-			reqHeader: "text/plain; foo=bar",
-			want:      false,
-		},
-	}
-	for _, tt := range tests {
-		req, err := http.NewRequest(http.MethodGet, "http://example.com/statusz", nil)
-		if err != nil {
-			t.Fatalf("Unexpected error while creating request: %v", err)
-		}
-
-		req.Header.Set("Accept", tt.reqHeader)
-		got := acceptableMediaType(req)
-
-		if got != tt.want {
-			t.Errorf("Unexpected response from acceptableMediaType(), want %v, got = %v", tt.want, got)
-		}
-	}
-}
-
 func parseVersion(t *testing.T, v string) *version.Version {
 	parsed, err := version.ParseMajorMinor(v)
 	if err != nil {