Print access logs for rejected requests and warn about new behavior

pkg/server/router/deny_test.go

@@ -0,0 +1,98 @@
+package router
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_denyFragment(t *testing.T) {
+	tests := []struct {
+		name       string
+		url        string
+		wantStatus int
+	}{
+		{
+			name:       "Rejects fragment character",
+			url:        "http://example.com/#",
+			wantStatus: http.StatusBadRequest,
+		},
+		{
+			name:       "Allows without fragment",
+			url:        "http://example.com/",
+			wantStatus: http.StatusOK,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			handler := denyFragment(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+			}))
+
+			req := httptest.NewRequest(http.MethodGet, test.url, nil)
+			res := httptest.NewRecorder()
+
+			handler.ServeHTTP(res, req)
+
+			assert.Equal(t, test.wantStatus, res.Code)
+		})
+	}
+}
+
+func Test_denyEncodedPathCharacters(t *testing.T) {
+	tests := []struct {
+		name       string
+		encoded    map[string]struct{}
+		url        string
+		wantStatus int
+	}{
+		{
+			name: "Rejects disallowed characters",
+			encoded: map[string]struct{}{
+				"%0A": {},
+				"%0D": {},
+			},
+			url:        "http://example.com/foo%0Abar",
+			wantStatus: http.StatusBadRequest,
+		},
+		{
+			name: "Allows valid paths",
+			encoded: map[string]struct{}{
+				"%0A": {},
+				"%0D": {},
+			},
+			url:        "http://example.com/foo%20bar",
+			wantStatus: http.StatusOK,
+		},
+		{
+			name: "Handles empty path",
+			encoded: map[string]struct{}{
+				"%0A": {},
+			},
+			url:        "http://example.com/",
+			wantStatus: http.StatusOK,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			handler := denyEncodedPathCharacters(test.encoded, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+			}))
+
+			req := httptest.NewRequest(http.MethodGet, test.url, nil)
+			res := httptest.NewRecorder()
+
+			handler.ServeHTTP(res, req)
+
+			assert.Equal(t, test.wantStatus, res.Code)
+		})
+	}
+}