fix reaction's name validation with + sign in it (#6221)

api4/api.go

@@ -90,7 +90,7 @@ type Routes struct {
 	Emojis *mux.Router // 'api/v4/emoji'
 	Emoji  *mux.Router // 'api/v4/emoji/{emoji_id:[A-Za-z0-9]+}'
 
-	ReactionByNameForPostForUser *mux.Router // 'api/v4/users/{user_id:[A-Za-z0-9]+}/posts/{post_id:[A-Za-z0-9]+}/reactions/{emoji_name:[A-Za-z0-9_-]+}'
+	ReactionByNameForPostForUser *mux.Router // 'api/v4/users/{user_id:[A-Za-z0-9]+}/posts/{post_id:[A-Za-z0-9]+}/reactions/{emoji_name:[A-Za-z0-9_-+]+}'
 
 	Webrtc *mux.Router // 'api/v4/webrtc'
 }
@@ -170,7 +170,7 @@ func InitApi(full bool) {
 	BaseRoutes.Emojis = BaseRoutes.ApiRoot.PathPrefix("/emoji").Subrouter()
 	BaseRoutes.Emoji = BaseRoutes.Emojis.PathPrefix("/{emoji_id:[A-Za-z0-9]+}").Subrouter()
 
-	BaseRoutes.ReactionByNameForPostForUser = BaseRoutes.PostForUser.PathPrefix("/reactions/{emoji_name:[A-Za-z0-9_-]+}").Subrouter()
+	BaseRoutes.ReactionByNameForPostForUser = BaseRoutes.PostForUser.PathPrefix("/reactions/{emoji_name:[A-Za-z0-9\\_\\-\\+]+}").Subrouter()
 
 	BaseRoutes.Webrtc = BaseRoutes.ApiRoot.PathPrefix("/webrtc").Subrouter()