Merge ce6939ce4090aa41861cd93daccce4b68f891b25 into 5fad976b372e381312f8de69f0969f1284d229d3

* fix: call updateRouteTrees in ServeHTTP using sync.Once to support literal colon routes in all usage scenarios (#4413)

* chore: fixed golangci-lint issue in test cases for literal colon

* fix: gofumpt formatting issue

* fix: gofumpt issue in gin.go

* chore: updated routeTreesUpdated comments

* chore: removed unused variable and updated TestUpdateRouteTreesCalledOnce testcase

* chore: moved tests from literal_colon_test.go into gin_test.go

---------

Co-authored-by: pawannn <pawan@zenz.tech>

.golangci.yml

@@ -18,15 +18,8 @@ linters:
     - wastedassign
   settings:
     gosec:
-      includes:
-        - G102
-        - G106
-        - G108
-        - G109
-        - G111
-        - G112
-        - G201
-        - G203
+      excludes:
+        - G115
     perfsprint:
       int-conversion: true
       err-error: true

context.go

@@ -55,6 +55,14 @@ const ContextRequestKey ContextKeyType = 0
 // abortIndex represents a typical value used in abort functions.
 const abortIndex int8 = math.MaxInt8 >> 1
 
+// safeInt8 converts int to int8 safely, capping at math.MaxInt8
+func safeInt8(n int) int8 {
+	if n > math.MaxInt8 {
+		return math.MaxInt8
+	}
+	return int8(n)
+}
+
 // Context is the most important part of gin. It allows us to pass variables between middleware,
 // manage the flow, validate the JSON of a request and render a JSON response for example.
 type Context struct {
@@ -186,7 +194,7 @@ func (c *Context) FullPath() string {
 // See example in GitHub.
 func (c *Context) Next() {
 	c.index++
-	for c.index < int8(len(c.handlers)) {
+	for c.index < safeInt8(len(c.handlers)) {
 		if c.handlers[c.index] != nil {
 			c.handlers[c.index](c)
 		}

docs/doc.md

@@ -9,6 +9,7 @@
   - [Using GET, POST, PUT, PATCH, DELETE and OPTIONS](#using-get-post-put-patch-delete-and-options)
   - [Parameters in path](#parameters-in-path)
   - [Querystring parameters](#querystring-parameters)
+  - [Retrieving the path of a registered handler](#retrieving-the-path-of-a-registered-handler)
   - [Multipart/Urlencoded Form](#multiparturlencoded-form)
   - [Another example: query + post form](#another-example-query--post-form)
   - [Map as querystring or postform parameters](#map-as-querystring-or-postform-parameters)
@@ -184,6 +185,29 @@ func main() {
 }
 ```
 
+### Retrieving the path of a registered handler
+
+Once a handler is registered with the router, you can retrieve its path with the `PathFor` method:
+
+```go
+func main() {
+  // Creates a gin router with default middleware:
+  // logger and recovery (crash-free) middleware
+  router := gin.Default()
+
+  getUser := func(c *Context) {
+    // Handle the GET request.
+  }
+  router.GET("/users/:name", getUser)
+  path := router.PathFor(getUser, ":name", "gopher")
+
+  print(path) // Prints /users/gopher
+
+  router.Run()
+}
+router := gin.Default()
+```
+
 ### Multipart/Urlencoded Form
 
 ```go

gin.go

@@ -23,10 +23,12 @@ import (
 	"golang.org/x/net/http2/h2c"
 )
 
-const defaultMultipartMemory = 32 << 20 // 32 MB
-const escapedColon = "\\:"
-const colon = ":"
-const backslash = "\\"
+const (
+	defaultMultipartMemory = 32 << 20 // 32 MB
+	escapedColon           = "\\:"
+	colon                  = ":"
+	backslash              = "\\"
+)
 
 var (
 	default404Body = []byte("404 page not found")
@@ -46,8 +48,10 @@ var defaultTrustedCIDRs = []*net.IPNet{
 	},
 }
 
-var regSafePrefix = regexp.MustCompile("[^a-zA-Z0-9/-]+")
-var regRemoveRepeatedChar = regexp.MustCompile("/{2,}")
+var (
+	regSafePrefix         = regexp.MustCompile("[^a-zA-Z0-9/-]+")
+	regRemoveRepeatedChar = regexp.MustCompile("/{2,}")
+)
 
 // HandlerFunc defines the handler used by gin middleware as return value.
 type HandlerFunc func(*Context)
@@ -94,6 +98,10 @@ const (
 type Engine struct {
 	RouterGroup
 
+	// routeTreesUpdated ensures that the initialization or update of the route trees
+	// (used for routing HTTP requests) happens only once, even if called multiple times concurrently.
+	routeTreesUpdated sync.Once
+
 	// RedirectTrailingSlash enables automatic redirection if the current route can't be matched but a
 	// handler for the path with (without) the trailing slash exists.
 	// For example if /foo/ is requested but a route only exists for /foo, the
@@ -384,6 +392,24 @@ func (engine *Engine) Routes() (routes RoutesInfo) {
 	return routes
 }
 
+// Routes returns a slice of registered routes, including some useful information, such as:
+// the http method, path and the handler name.
+func (engine *Engine) Route(handler HandlerFunc) (route RouteInfo, ok bool) {
+	handlerName := nameOfFunction(handler)
+	routes := RoutesInfo{}
+	for _, tree := range engine.trees {
+		routes = iterate("", tree.method, routes, tree.root)
+
+		for _, route := range routes {
+			if route.Handler == handlerName {
+				return route, true
+			}
+		}
+	}
+
+	return RouteInfo{}, false
+}
+
 func iterate(path, method string, routes RoutesInfo, root *node) RoutesInfo {
 	path += root.path
 	if len(root.handlers) > 0 {
@@ -537,7 +563,11 @@ func (engine *Engine) Run(addr ...string) (err error) {
 	engine.updateRouteTrees()
 	address := resolveAddress(addr)
 	debugPrint("Listening and serving HTTP on %s\n", address)
-	err = http.ListenAndServe(address, engine.Handler())
+	server := &http.Server{ // #nosec G112
+		Addr:    address,
+		Handler: engine.Handler(),
+	}
+	err = server.ListenAndServe()
 	return
 }
 
@@ -553,7 +583,11 @@ func (engine *Engine) RunTLS(addr, certFile, keyFile string) (err error) {
 			"Please check https://github.com/gin-gonic/gin/blob/master/docs/doc.md#dont-trust-all-proxies for details.")
 	}
 
-	err = http.ListenAndServeTLS(addr, certFile, keyFile, engine.Handler())
+	server := &http.Server{ // #nosec G112
+		Addr:    addr,
+		Handler: engine.Handler(),
+	}
+	err = server.ListenAndServeTLS(certFile, keyFile)
 	return
 }
 
@@ -576,7 +610,10 @@ func (engine *Engine) RunUnix(file string) (err error) {
 	defer listener.Close()
 	defer os.Remove(file)
 
-	err = http.Serve(listener, engine.Handler())
+	server := &http.Server{ // #nosec G112
+		Handler: engine.Handler(),
+	}
+	err = server.Serve(listener)
 	return
 }
 
@@ -630,12 +667,19 @@ func (engine *Engine) RunListener(listener net.Listener) (err error) {
 			"Please check https://github.com/gin-gonic/gin/blob/master/docs/doc.md#dont-trust-all-proxies for details.")
 	}
 
-	err = http.Serve(listener, engine.Handler())
+	server := &http.Server{ // #nosec G112
+		Handler: engine.Handler(),
+	}
+	err = server.Serve(listener)
 	return
 }
 
 // ServeHTTP conforms to the http.Handler interface.
 func (engine *Engine) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	engine.routeTreesUpdated.Do(func() {
+		engine.updateRouteTrees()
+	})
+
 	c := engine.pool.Get().(*Context)
 	c.writermem.reset(w)
 	c.Request = req
@@ -659,6 +703,43 @@ func (engine *Engine) HandleContext(c *Context) {
 	c.handlers = oldHandlers
 }
 
+// PathFor returns the path registered for the specified handler function.
+// Route values are passed pair-wise as key value.
+func (engine *Engine) PathFor(handler HandlerFunc, values ...interface{}) string {
+	route, ok := engine.Route(handler)
+
+	if !ok || len(route.Path) == 0 || len(values)%2 != 0 {
+		return ""
+	}
+
+	url := route.Path
+	params := make(map[string]string)
+	if len(values) > 0 {
+		key := ""
+		for k, v := range values {
+			if k%2 == 0 {
+				key = fmt.Sprint(v)
+			} else {
+				params[key] = fmt.Sprint(v)
+			}
+		}
+	}
+	urls := strings.Split(url, "/")
+	for _, v := range urls {
+		if v == "" {
+			continue
+		}
+		if v[0:1] == ":" {
+			if u, ok := params[v]; ok {
+				delete(params, v)
+				url = strings.Replace(url, v, u, 1)
+			}
+		}
+	}
+
+	return url + toQuerystring(params)
+}
+
 func (engine *Engine) handleHTTPRequest(c *Context) {
 	httpMethod := c.Request.Method
 	rPath := c.Request.URL.Path
@@ -787,3 +868,14 @@ func redirectRequest(c *Context) {
 	http.Redirect(c.Writer, req, rURL, code)
 	c.writermem.WriteHeaderNow()
 }
+
+func toQuerystring(params map[string]string) string {
+	if len(params) == 0 {
+		return ""
+	}
+	u := "?"
+	for k, v := range params {
+		u += k + "=" + v + "&"
+	}
+	return strings.TrimRight(u, "&")
+}

gin_test.go

@@ -825,6 +825,25 @@ func TestPrepareTrustedCIRDsWith(t *testing.T) {
 	}
 }
 
+func TestPathFor(t *testing.T) {
+	r := New()
+
+	getIndex := func(c *Context) {}
+	r.GET("/", getIndex)
+
+	users := r.Group("/users")
+
+	postUser := func(c *Context) {}
+	users.POST("", postUser)
+
+	getUser := func(c *Context) {}
+	users.GET("/:name", getUser)
+
+	assert.Equal(t, "/", r.PathFor(getIndex))
+	assert.Equal(t, "/users", r.PathFor(postUser))
+	assert.Equal(t, "/users/gopher", r.PathFor(getUser, ":name", "gopher"))
+}
+
 func parseCIDR(cidr string) *net.IPNet {
 	_, parsedCIDR, err := net.ParseCIDR(cidr)
 	if err != nil {
@@ -913,3 +932,102 @@ func TestMethodNotAllowedNoRoute(t *testing.T) {
 	assert.NotPanics(t, func() { g.ServeHTTP(resp, req) })
 	assert.Equal(t, http.StatusNotFound, resp.Code)
 }
+
+// Test the fix for https://github.com/gin-gonic/gin/pull/4415
+func TestLiteralColonWithRun(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	router.updateRouteTrees()
+
+	w := httptest.NewRecorder()
+
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+}
+
+func TestLiteralColonWithDirectServeHTTP(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+}
+
+func TestLiteralColonWithHandler(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	handler := router.Handler()
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	handler.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+}
+
+func TestLiteralColonWithHTTPServer(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	router.GET("/test/:param", func(c *Context) {
+		c.JSON(http.StatusOK, H{"param": c.Param("param")})
+	})
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+
+	w2 := httptest.NewRecorder()
+	req2, _ := http.NewRequest(http.MethodGet, "/test/foo", nil)
+	router.ServeHTTP(w2, req2)
+
+	assert.Equal(t, http.StatusOK, w2.Code)
+	assert.Contains(t, w2.Body.String(), "foo")
+}
+
+// Test that updateRouteTrees is called only once
+func TestUpdateRouteTreesCalledOnce(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.String(http.StatusOK, "ok")
+	})
+
+	for range 5 {
+		w := httptest.NewRecorder()
+		req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+		router.ServeHTTP(w, req)
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Equal(t, "ok", w.Body.String())
+	}
+}

tree.go

@@ -5,6 +5,7 @@
 package gin
 
 import (
+	"math"
 	"net/url"
 	"strings"
 	"unicode"
@@ -77,14 +78,22 @@ func (n *node) addChild(child *node) {
 	}
 }
 
+// safeUint16 converts int to uint16 safely, capping at math.MaxUint16
+func safeUint16(n int) uint16 {
+	if n > math.MaxUint16 {
+		return math.MaxUint16
+	}
+	return uint16(n)
+}
+
 func countParams(path string) uint16 {
 	colons := strings.Count(path, ":")
 	stars := strings.Count(path, "*")
-	return uint16(colons + stars)
+	return safeUint16(colons + stars)
 }
 
 func countSections(path string) uint16 {
-	return uint16(strings.Count(path, "/"))
+	return safeUint16(strings.Count(path, "/"))
 }
 
 type nodeType uint8