diff --git a/PULL_REQUEST_TEMPLATE.md b/PULL_REQUEST_TEMPLATE.md
new file mode 100644
index 0000000..fd84126
--- /dev/null
+++ b/PULL_REQUEST_TEMPLATE.md
@@ -0,0 +1,8 @@
+**Describe the PR**
+e.g. add cool parser.
+
+**Relation issue**
+e.g. https://github.com/swaggo/gin-swagger/pull/123/files
+
+**Additional context**
+Add any other context about the problem here.
diff --git a/README.md b/README.md
index 3e8e321..2efc171 100644
--- a/README.md
+++ b/README.md
@@ -147,5 +147,6 @@ func main() {
 | Option                   | Type   | Default    | Description                                                               |
 |--------------------------|--------|------------|---------------------------------------------------------------------------|
 | URL                      | string | "doc.json" | URL pointing to API definition                                            |
-| DeepLinking              | bool   | true       | Swagger deeplinking configuration                                         |
+| DocExpantion             | string | "list"     | Controls the default expansion setting for the operations and tags. It can be 'list' (expands only the tags), 'full' (expands the tags and operations) or 'none' (expands nothing). |
+| DeepLinking              | bool   | true       | If set to true, enables deep linking for tags and operations. See the Deep Linking documentation for more information.|
 | DefaultModelsExpandDepth | int    | 1          | Default expansion depth for models (set to -1 completely hide the models) |
diff --git a/swagger.go b/swagger.go
index bed2193..7fb3462 100644
--- a/swagger.go
+++ b/swagger.go
@@ -4,8 +4,8 @@ import (
 	"html/template"
 	"net/http"
 	"os"
+	"path/filepath"
 	"regexp"
-	"strings"
 	"sync"
 
 	"golang.org/x/net/webdav"
@@ -19,6 +19,7 @@ type Config struct {
 	//The url pointing to API definition (normally swagger.json or swagger.yaml). Default is `doc.json`.
 	URL                      string
 	DeepLinking              bool
+	DocExpansion             string
 	DefaultModelsExpandDepth int
 }
 
@@ -29,6 +30,13 @@ func URL(url string) func(c *Config) {
 	}
 }
 
+// DocExpansion list, full, none.
+func DocExpansion(docExpansion string) func(c *Config) {
+	return func(c *Config) {
+		c.DocExpansion = docExpansion
+	}
+}
+
 // DeepLinking set the swagger deeplinking configuration
 func DeepLinking(deepLinking bool) func(c *Config) {
 	return func(c *Config) {
@@ -49,6 +57,7 @@ func WrapHandler(h *webdav.Handler, confs ...func(c *Config)) gin.HandlerFunc {
 	defaultConfig := &Config{
 		URL:                      "doc.json",
 		DeepLinking:              true,
+		DocExpansion:             "list",
 		DefaultModelsExpandDepth: 1,
 	}
 
@@ -60,52 +69,43 @@ func WrapHandler(h *webdav.Handler, confs ...func(c *Config)) gin.HandlerFunc {
 }
 
 // CustomWrapHandler wraps `http.Handler` into `gin.HandlerFunc`
-func CustomWrapHandler(config *Config, h *webdav.Handler) gin.HandlerFunc {
-	//create a template with name
+func CustomWrapHandler(config *Config, handler *webdav.Handler) gin.HandlerFunc {
+	var once sync.Once
+
+	// create a template with name
 	t := template.New("swagger_index.html")
 	index, _ := t.Parse(swagger_index_templ)
 
 	var rexp = regexp.MustCompile(`(.*)(index\.html|doc\.json|favicon-16x16\.png|favicon-32x32\.png|/oauth2-redirect\.html|swagger-ui\.css|swagger-ui\.css\.map|swagger-ui\.js|swagger-ui\.js\.map|swagger-ui-bundle\.js|swagger-ui-bundle\.js\.map|swagger-ui-standalone-preset\.js|swagger-ui-standalone-preset\.js\.map)[\?|.]*`)
-	var locker sync.RWMutex
 
 	return func(c *gin.Context) {
+		matches := rexp.FindStringSubmatch(c.Request.RequestURI)
 
-		type swaggerUIBundle struct {
-			URL                      string
-			DeepLinking              bool
-			DefaultModelsExpandDepth int
-		}
-
-		var matches []string
-		if matches = rexp.FindStringSubmatch(c.Request.RequestURI); len(matches) != 3 {
+		if len(matches) != 3 {
 			c.Status(404)
-			c.Writer.Write([]byte("404 page not found"))
+			_, _ = c.Writer.Write([]byte("404 page not found"))
 			return
 		}
+
 		path := matches[2]
-		prefix := matches[1]
+		once.Do(func() {
+			handler.Prefix = matches[1]
+		})
 
-		locker.Lock()
-		h.Prefix = prefix
-		locker.Unlock()
-
-		if strings.HasSuffix(path, ".html") {
+		switch filepath.Ext(path) {
+		case ".html":
 			c.Header("Content-Type", "text/html; charset=utf-8")
-		} else if strings.HasSuffix(path, ".css") {
+		case ".css":
 			c.Header("Content-Type", "text/css; charset=utf-8")
-		} else if strings.HasSuffix(path, ".js") {
+		case ".js":
 			c.Header("Content-Type", "application/javascript")
-		} else if strings.HasSuffix(path, ".json") {
+		case ".json":
 			c.Header("Content-Type", "application/json; charset=utf-8")
 		}
 
 		switch path {
 		case "index.html":
-			index.Execute(c.Writer, &swaggerUIBundle{
-				URL:                      config.URL,
-				DeepLinking:              config.DeepLinking,
-				DefaultModelsExpandDepth: config.DefaultModelsExpandDepth,
-			})
+			_ = index.Execute(c.Writer, config)
 		case "doc.json":
 			doc, err := swag.ReadDoc()
 			if err != nil {
@@ -113,11 +113,9 @@ func CustomWrapHandler(config *Config, h *webdav.Handler) gin.HandlerFunc {
 
 				return
 			}
-			c.Writer.Write([]byte(doc))
+			_, _ = c.Writer.Write([]byte(doc))
 		default:
-			locker.RLock()
-			h.ServeHTTP(c.Writer, c.Request)
-			locker.RUnlock()
+			handler.ServeHTTP(c.Writer, c.Request)
 		}
 	}
 }
@@ -238,6 +236,7 @@ window.onload = function() {
       SwaggerUIBundle.plugins.DownloadUrl
     ],
 	layout: "StandaloneLayout",
+    docExpansion: "{{.DocExpansion}}",
 	deepLinking: {{.DeepLinking}},
 	defaultModelsExpandDepth: {{.DefaultModelsExpandDepth}}
   })
diff --git a/swagger_test.go b/swagger_test.go
index 567fc96..aa6a0d1 100644
--- a/swagger_test.go
+++ b/swagger_test.go
@@ -1,13 +1,14 @@
 package ginSwagger
 
 import (
-	"github.com/gin-contrib/gzip"
-	"github.com/swaggo/swag"
-
 	"net/http/httptest"
 	"os"
+	"path/filepath"
 	"testing"
 
+	"github.com/gin-contrib/gzip"
+	"github.com/swaggo/swag"
+
 	"github.com/gin-gonic/gin"
 	"github.com/stretchr/testify/assert"
 	"github.com/swaggo/gin-swagger/swaggerFiles"
@@ -74,7 +75,7 @@ func TestDisablingWrapHandler(t *testing.T) {
 	w4 := performRequest("GET", "/simple/notfound", router)
 	assert.Equal(t, 404, w4.Code)
 
-	os.Setenv(disablingKey, "true")
+	_ = os.Setenv(disablingKey, "true")
 
 	router.GET("/disabling/*any", DisablingWrapHandler(swaggerFiles.Handler, disablingKey))
 
@@ -102,7 +103,7 @@ func TestDisablingCustomWrapHandler(t *testing.T) {
 	w1 := performRequest("GET", "/simple/index.html", router)
 	assert.Equal(t, 200, w1.Code)
 
-	os.Setenv(disablingKey, "true")
+	_ = os.Setenv(disablingKey, "true")
 
 	router.GET("/disabling/*any", DisablingCustomWrapHandler(&Config{}, swaggerFiles.Handler, disablingKey))
 
@@ -143,25 +144,63 @@ func performRequest(method, target string, router *gin.Engine) *httptest.Respons
 }
 
 func TestURL(t *testing.T) {
-	expected := "https://github.com/swaggo/http-swagger"
 	cfg := Config{}
+
+	expected := "https://github.com/swaggo/http-swagger"
 	configFunc := URL(expected)
 	configFunc(&cfg)
 	assert.Equal(t, expected, cfg.URL)
 }
 
-func TestDeepLinking(t *testing.T) {
-	expected := true
-	cfg := Config{}
-	configFunc := DeepLinking(expected)
+func TestDocExpansion(t *testing.T) {
+	var cfg Config
+
+	expected := "list"
+	configFunc := DocExpansion(expected)
 	configFunc(&cfg)
-	assert.Equal(t, expected, cfg.DeepLinking)
+	assert.Equal(t, expected, cfg.DocExpansion)
+
+	expected = "full"
+	configFunc = DocExpansion(expected)
+	configFunc(&cfg)
+	assert.Equal(t, expected, cfg.DocExpansion)
+
+	expected = "none"
+	configFunc = DocExpansion(expected)
+	configFunc(&cfg)
+	assert.Equal(t, expected, cfg.DocExpansion)
+}
+
+func TestDeepLinking(t *testing.T) {
+	var cfg Config
+	assert.Equal(t, false, cfg.DeepLinking)
+
+	configFunc := DeepLinking(true)
+	configFunc(&cfg)
+	assert.Equal(t, true, cfg.DeepLinking)
+
+	configFunc = DeepLinking(false)
+	configFunc(&cfg)
+	assert.Equal(t, false, cfg.DeepLinking)
+
 }
 
 func TestDefaultModelsExpandDepth(t *testing.T) {
+	var cfg Config
+
+	assert.Equal(t, 0, cfg.DefaultModelsExpandDepth)
+
 	expected := -1
-	cfg := Config{}
 	configFunc := DefaultModelsExpandDepth(expected)
 	configFunc(&cfg)
 	assert.Equal(t, expected, cfg.DefaultModelsExpandDepth)
+
+	expected = 1
+	configFunc = DefaultModelsExpandDepth(expected)
+	configFunc(&cfg)
+	assert.Equal(t, expected, cfg.DefaultModelsExpandDepth)
+}
+
+func TestDeepLinking2(t *testing.T) {
+	t.Logf("extension: %s", filepath.Ext("/asas/index.html"))
 }