config, apiserver, swaggerserver: fix path prefix handling

cmd/tidb-dashboard/main.go

@@ -273,16 +273,21 @@ func main() {
 	defer s.Stop(context.Background()) //nolint:errcheck
 
 	mux := http.DefaultServeMux
-	uiHandler := http.StripPrefix(strings.TrimRight(config.UIPathPrefix, "/"), uiserver.Handler(assets))
-	mux.Handle("/", http.RedirectHandler(config.UIPathPrefix, http.StatusFound))
-	mux.Handle(config.UIPathPrefix, uiHandler)
-	mux.Handle(config.APIPathPrefix, apiserver.Handler(s))
-	mux.Handle(config.SwaggerPathPrefix, swaggerserver.Handler())
+	uiPathPrefix := cliConfig.CoreConfig.UIPathPrefix()
+	apiPathPrefix := cliConfig.CoreConfig.APIPathPrefix()
+	swaggerPathPrefix := cliConfig.CoreConfig.SwaggerPathPrefix()
+	uiHandler := http.StripPrefix(strings.TrimRight(uiPathPrefix, "/"), uiserver.Handler(assets))
+	if uiPathPrefix != "/" {
+		mux.Handle("/", http.RedirectHandler(uiPathPrefix, http.StatusFound))
+	}
+	mux.Handle(uiPathPrefix, uiHandler)
+	mux.Handle(apiPathPrefix, apiserver.Handler(s))
+	mux.Handle(swaggerPathPrefix, swaggerserver.Handler(cliConfig.CoreConfig))
 
 	log.Info(fmt.Sprintf("Dashboard server is listening at %s", listenAddr))
-	log.Info(fmt.Sprintf("UI:      http://%s/dashboard/", net.JoinHostPort(cliConfig.ListenHost, strconv.Itoa(cliConfig.ListenPort))))
-	log.Info(fmt.Sprintf("API:     http://%s/dashboard/api/", net.JoinHostPort(cliConfig.ListenHost, strconv.Itoa(cliConfig.ListenPort))))
-	log.Info(fmt.Sprintf("Swagger: http://%s/dashboard/api/swagger/", net.JoinHostPort(cliConfig.ListenHost, strconv.Itoa(cliConfig.ListenPort))))
+	log.Info(fmt.Sprintf("UI:      http://%s%s", listenAddr, uiPathPrefix))
+	log.Info(fmt.Sprintf("API:     http://%s%s", listenAddr, apiPathPrefix))
+	log.Info(fmt.Sprintf("Swagger: http://%s%s", listenAddr, swaggerPathPrefix))
 
 	srv := &http.Server{Handler: mux} // nolint:gosec
 	var wg sync.WaitGroup

pkg/apiserver/apiserver.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"io"
 	"net/http"
+	"strings"
 	"sync"
 
 	"github.com/gin-contrib/gzip"
@@ -270,14 +271,14 @@ func (s *Service) provideLocals() (*config.Config, http.FileSystem, *keyvisualre
 	return s.config, s.uiAssetFS, s.customKeyVisualProvider
 }
 
-func newAPIHandlerEngine() (apiHandlerEngine *gin.Engine, endpoint *gin.RouterGroup) {
+func newAPIHandlerEngine(cfg *config.Config) (apiHandlerEngine *gin.Engine, endpoint *gin.RouterGroup) {
 	apiHandlerEngine = gin.New()
 	apiHandlerEngine.Use(gin.Recovery())
 	apiHandlerEngine.Use(cors.AllowAll())
 	apiHandlerEngine.Use(gzip.Gzip(gzip.DefaultCompression))
 	apiHandlerEngine.Use(rest.ErrorHandlerFn())
 
-	endpoint = apiHandlerEngine.Group("/dashboard/api")
+	endpoint = apiHandlerEngine.Group(strings.TrimRight(cfg.APIPathPrefix(), "/"))
 
 	return
 }

pkg/apiserver/apiserver_test.go

@@ -0,0 +1,40 @@
+// Copyright 2026 PingCAP, Inc. Licensed under Apache-2.0.
+
+package apiserver
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/pingcap/tidb-dashboard/pkg/config"
+)
+
+func TestNewAPIHandlerEngineUsesPublicPathPrefix(t *testing.T) {
+	cfg := config.Default()
+	cfg.PublicPathPrefix = "/test"
+	cfg.NormalizePublicPathPrefix()
+
+	engine, endpoint := newAPIHandlerEngine(cfg)
+	endpoint.GET("/ping", func(c *gin.Context) {
+		c.String(http.StatusOK, "pong")
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/test/api/ping", nil)
+	rec := httptest.NewRecorder()
+	engine.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("GET /test/api/ping status = %d, want %d", rec.Code, http.StatusOK)
+	}
+
+	req = httptest.NewRequest(http.MethodGet, "/dashboard/api/ping", nil)
+	rec = httptest.NewRecorder()
+	engine.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusNotFound {
+		t.Fatalf("GET /dashboard/api/ping status = %d, want %d", rec.Code, http.StatusNotFound)
+	}
+}

pkg/config/config.go

@@ -12,13 +12,7 @@ import (
 	"github.com/pingcap/tidb-dashboard/pkg/utils/version"
 )
 
-const (
-	defaultPublicPathPrefix = "/dashboard"
-
-	UIPathPrefix      = "/dashboard/"
-	APIPathPrefix     = "/dashboard/api/"
-	SwaggerPathPrefix = "/dashboard/api/swagger/"
-)
+const defaultPublicPathPrefix = "/dashboard"
 
 type Config struct {
 	DataDir          string
@@ -82,6 +76,24 @@ func (c *Config) NormalizePDEndPoint() error {
 func (c *Config) NormalizePublicPathPrefix() {
 	if c.PublicPathPrefix == "" {
 		c.PublicPathPrefix = defaultPublicPathPrefix
+		return
+	}
+	trimmed := strings.Trim(c.PublicPathPrefix, "/")
+	if trimmed == "" {
+		c.PublicPathPrefix = ""
+		return
 	}
-	c.PublicPathPrefix = strings.TrimRight(c.PublicPathPrefix, "/")
+	c.PublicPathPrefix = "/" + trimmed
+}
+
+func (c *Config) UIPathPrefix() string {
+	return c.PublicPathPrefix + "/"
+}
+
+func (c *Config) APIPathPrefix() string {
+	return c.PublicPathPrefix + "/api/"
+}
+
+func (c *Config) SwaggerPathPrefix() string {
+	return c.PublicPathPrefix + "/api/swagger/"
 }

pkg/config/config_test.go

@@ -0,0 +1,77 @@
+// Copyright 2026 PingCAP, Inc. Licensed under Apache-2.0.
+
+package config
+
+import "testing"
+
+func TestNormalizePublicPathPrefix(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		prefix  string
+		ui      string
+		api     string
+		swagger string
+	}{
+		{
+			name:    "empty uses default",
+			input:   "",
+			prefix:  "/dashboard",
+			ui:      "/dashboard/",
+			api:     "/dashboard/api/",
+			swagger: "/dashboard/api/swagger/",
+		},
+		{
+			name:    "custom with leading slash",
+			input:   "/test",
+			prefix:  "/test",
+			ui:      "/test/",
+			api:     "/test/api/",
+			swagger: "/test/api/swagger/",
+		},
+		{
+			name:    "custom with trailing slash",
+			input:   "/test/",
+			prefix:  "/test",
+			ui:      "/test/",
+			api:     "/test/api/",
+			swagger: "/test/api/swagger/",
+		},
+		{
+			name:    "custom without leading slash",
+			input:   "test",
+			prefix:  "/test",
+			ui:      "/test/",
+			api:     "/test/api/",
+			swagger: "/test/api/swagger/",
+		},
+		{
+			name:    "root prefix",
+			input:   "/",
+			prefix:  "",
+			ui:      "/",
+			api:     "/api/",
+			swagger: "/api/swagger/",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := &Config{PublicPathPrefix: tt.input}
+			cfg.NormalizePublicPathPrefix()
+
+			if cfg.PublicPathPrefix != tt.prefix {
+				t.Fatalf("PublicPathPrefix = %q, want %q", cfg.PublicPathPrefix, tt.prefix)
+			}
+			if cfg.UIPathPrefix() != tt.ui {
+				t.Fatalf("UIPathPrefix() = %q, want %q", cfg.UIPathPrefix(), tt.ui)
+			}
+			if cfg.APIPathPrefix() != tt.api {
+				t.Fatalf("APIPathPrefix() = %q, want %q", cfg.APIPathPrefix(), tt.api)
+			}
+			if cfg.SwaggerPathPrefix() != tt.swagger {
+				t.Fatalf("SwaggerPathPrefix() = %q, want %q", cfg.SwaggerPathPrefix(), tt.swagger)
+			}
+		})
+	}
+}

pkg/swaggerserver/handler.go

@@ -4,12 +4,15 @@ package swaggerserver
 
 import (
 	"net/http"
+	"strings"
 
 	httpSwagger "github.com/swaggo/http-swagger"
-	// Swagger doc.
-	_ "github.com/pingcap/tidb-dashboard/swaggerspec"
+
+	"github.com/pingcap/tidb-dashboard/pkg/config"
+	"github.com/pingcap/tidb-dashboard/swaggerspec"
 )
 
-func Handler() http.Handler {
+func Handler(cfg *config.Config) http.Handler {
+	swaggerspec.SwaggerInfo_swagger.BasePath = strings.TrimRight(cfg.APIPathPrefix(), "/")
 	return httpSwagger.Handler()
 }

pkg/swaggerserver/handler_test.go

@@ -0,0 +1,27 @@
+// Copyright 2026 PingCAP, Inc. Licensed under Apache-2.0.
+
+package swaggerserver
+
+import (
+	"testing"
+
+	"github.com/pingcap/tidb-dashboard/pkg/config"
+	"github.com/pingcap/tidb-dashboard/swaggerspec"
+)
+
+func TestHandlerUpdatesSwaggerBasePath(t *testing.T) {
+	basePath := swaggerspec.SwaggerInfo_swagger.BasePath
+	t.Cleanup(func() {
+		swaggerspec.SwaggerInfo_swagger.BasePath = basePath
+	})
+
+	cfg := config.Default()
+	cfg.PublicPathPrefix = "/test"
+	cfg.NormalizePublicPathPrefix()
+
+	Handler(cfg)
+
+	if swaggerspec.SwaggerInfo_swagger.BasePath != "/test/api" {
+		t.Fatalf("basePath = %q, want %q", swaggerspec.SwaggerInfo_swagger.BasePath, "/test/api")
+	}
+}

ui/packages/tidb-dashboard-for-op/src/utils/publicPathPrefix.ts

@@ -1,9 +1,8 @@
 const DEF_PUBLIC_PATH_PREFIX = '/dashboard'
 
-let prefix =
-  document
-    .querySelector('meta[name="x-public-path-prefix"]')
-    ?.getAttribute('content') || DEF_PUBLIC_PATH_PREFIX
+let prefix = document
+  .querySelector('meta[name="x-public-path-prefix"]')
+  ?.getAttribute('content') ?? DEF_PUBLIC_PATH_PREFIX
 
 if (prefix === '__PUBLIC_PATH_PREFIX__') {
   prefix = DEF_PUBLIC_PATH_PREFIX