feat(router): add literal colon support (#1432)

gin.go

@@ -24,6 +24,9 @@ import (
 )
 
 const defaultMultipartMemory = 32 << 20 // 32 MB
+const escapedColon = "\\:"
+const colon = ":"
+const backslash = "\\"
 
 var (
 	default404Body = []byte("404 page not found")
@@ -474,6 +477,26 @@ func (engine *Engine) validateHeader(header string) (clientIP string, valid bool
 	return "", false
 }
 
+// updateRouteTree do update to the route tree recursively
+func updateRouteTree(n *node) {
+	n.path = strings.ReplaceAll(n.path, escapedColon, colon)
+	n.fullPath = strings.ReplaceAll(n.fullPath, escapedColon, colon)
+	n.indices = strings.ReplaceAll(n.indices, backslash, colon)
+	if n.children == nil {
+		return
+	}
+	for _, child := range n.children {
+		updateRouteTree(child)
+	}
+}
+
+// updateRouteTrees do update to the route trees
+func (engine *Engine) updateRouteTrees() {
+	for _, tree := range engine.trees {
+		updateRouteTree(tree.root)
+	}
+}
+
 // parseIP parse a string representation of an IP and returns a net.IP with the
 // minimum byte representation or nil if input is invalid.
 func parseIP(ip string) net.IP {
@@ -498,7 +521,7 @@ func (engine *Engine) Run(addr ...string) (err error) {
 		debugPrint("[WARNING] You trusted all proxies, this is NOT safe. We recommend you to set a value.\n" +
 			"Please check https://github.com/gin-gonic/gin/blob/master/docs/doc.md#dont-trust-all-proxies for details.")
 	}
-
+	engine.updateRouteTrees()
 	address := resolveAddress(addr)
 	debugPrint("Listening and serving HTTP on %s\n", address)
 	err = http.ListenAndServe(address, engine.Handler())

gin_integration_test.go

@@ -577,3 +577,28 @@ func TestTreeRunDynamicRouting(t *testing.T) {
 func isWindows() bool {
 	return runtime.GOOS == "windows"
 }
+
+func TestEscapedColon(t *testing.T) {
+	router := New()
+	f := func(u string) {
+		router.GET(u, func(c *Context) { c.String(http.StatusOK, u) })
+	}
+	f("/r/r\\:r")
+	f("/r/r:r")
+	f("/r/r/:r")
+	f("/r/r/\\:r")
+	f("/r/r/r\\:r")
+	assert.Panics(t, func() {
+		f("\\foo:")
+	})
+
+	router.updateRouteTrees()
+	ts := httptest.NewServer(router)
+	defer ts.Close()
+
+	testRequest(t, ts.URL+"/r/r123", "", "/r/r:r")
+	testRequest(t, ts.URL+"/r/r:r", "", "/r/r\\:r")
+	testRequest(t, ts.URL+"/r/r/r123", "", "/r/r/:r")
+	testRequest(t, ts.URL+"/r/r/:r", "", "/r/r/\\:r")
+	testRequest(t, ts.URL+"/r/r/r:r", "", "/r/r/r\\:r")
+}

tree.go

@@ -269,7 +269,19 @@ walk:
 // Returns -1 as index, if no wildcard was found.
 func findWildcard(path string) (wildcard string, i int, valid bool) {
 	// Find start
+	escapeColon := false
 	for start, c := range []byte(path) {
+		if escapeColon {
+			escapeColon = false
+			if c == ':' {
+				continue
+			}
+			panic("invalid escape string in path '" + path + "'")
+		}
+		if c == '\\' {
+			escapeColon = true
+			continue
+		}
 		// A wildcard starts with ':' (param) or '*' (catch-all)
 		if c != ':' && c != '*' {
 			continue

tree_test.go

@@ -192,6 +192,7 @@ func TestTreeWildcard(t *testing.T) {
 		"/get/abc/123abg/:param",
 		"/get/abc/123abf/:param",
 		"/get/abc/123abfff/:param",
+		"/get/abc/escaped_colon/test\\:param",
 	}
 	for _, route := range routes {
 		tree.addRoute(route, fakeHandler(route))
@@ -315,6 +316,7 @@ func TestTreeWildcard(t *testing.T) {
 		{"/get/abc/123abg/test", false, "/get/abc/123abg/:param", Params{Param{Key: "param", Value: "test"}}},
 		{"/get/abc/123abf/testss", false, "/get/abc/123abf/:param", Params{Param{Key: "param", Value: "testss"}}},
 		{"/get/abc/123abfff/te", false, "/get/abc/123abfff/:param", Params{Param{Key: "param", Value: "te"}}},
+		{"/get/abc/escaped_colon/test\\:param", false, "/get/abc/escaped_colon/test\\:param", nil},
 	})
 
 	checkPriorities(t, tree)
@@ -419,6 +421,9 @@ func TestTreeWildcardConflict(t *testing.T) {
 		{"/id/:id", false},
 		{"/static/*file", false},
 		{"/static/", true},
+		{"/escape/test\\:d1", false},
+		{"/escape/test\\:d2", false},
+		{"/escape/test:param", false},
 	}
 	testRoutes(t, routes)
 }
@@ -971,3 +976,20 @@ func TestTreeWildcardConflictEx(t *testing.T) {
 		}
 	}
 }
+
+func TestTreeInvalidEscape(t *testing.T) {
+	routes := map[string]bool{
+		"/r1/r":    true,
+		"/r2/:r":   true,
+		"/r3/\\:r": true,
+	}
+	tree := &node{}
+	for route, valid := range routes {
+		recv := catchPanic(func() {
+			tree.addRoute(route, fakeHandler(route))
+		})
+		if recv == nil != valid {
+			t.Fatalf("%s should be %t but got %v", route, valid, recv)
+		}
+	}
+}