无法将String转换为* net.TCP侦听器类型

Question

i want to put string in net.Listener but i got error :

./server.go:26:23: cannot use mainServer (type interface {}) as type string in argument to net.Listen: need type assertion
./server.go:27:28: cannot use gpServer (type interface {}) as type string in argument to net.Listen: need type assertion

its my code :

  viper.SetConfigFile("config.json")
  viper.AddConfigPath(".")
  viper.SetConfigName("config")
  viper.ReadInConfig()
  fmt.Printf("Using config: %s
", viper.ConfigFileUsed())
  mainServer := viper.Get("mainServer.port")
  gpServer := viper.Get("gpServer.port")

  fmt.Println(mainServer,gpServer)



  fmt.Println("started main server")
  ln, _ := net.Listen("tcp", mainServer)
  gp_conn, _ := net.Listen("tcp", gpServer)

its my config.json :

    "mainServer": {
        "host": "",
        "port": ":2323",
        "enabled": true
    },
    "gpServer": {
        "host": "",
        "port": ":3232",
        "enabled": true
    }
}

can some one explain me how i can convert string to net.TCPListener Type ? tnx

Answer 1

I believe the method viper.GetString would work better than viper.Get based on the documentation: fyi, you can take a look at these things here: https://godoc.org/github.com/spf13/viper

mainServer := viper.GetString("mainServer.port")
gpServer := viper.GetString("gpServer.port")

However, you could assert the type directly... Bear in mind this is ill-advised, you shouldn't do this as it will result in a panic if the type is not a string AND viper has the convenience method used above.

ln, _ := net.Listen("tcp", mainServer.(string))
gp_conn, _ := net.Listen("tcp", gpServer.(string))