我正在尝试将旧的.js api调用转换为我的swift应用程序。在.js中，我必须发送带有api网址的查询，以决定要接收哪些字段。

例如“ https://api.myapi.com/planner?query=”和content.txt

content.txt

{
    places(
        ids:["ABC:StopPlace:8329","ABC:StopPlace:9237"]
    ) {
        name
        id
        estimatedCalls(timeRange: 72100,numberOfDepartures: 20) {

            realtime
            realtimeState
            expectedDepartureTime
            predictionInaccurate
            destinationDisplay {
                frontText
            }

        }
    }
}

现在我正在尝试：

func loadR(filename: String ) -> String  {

        let url = Bundle.main.url(forResource: filename,withExtension: "txt")!
        let data = try! Data(contentsof: url)
        let string = String(data: data,encoding: .utf8)!
        print(string)

        self.load(q: string)
        return string
}


func load(q: String) {
   var urlQ = "https://api.apisite.com/planner?query=" + q

   let url = URL(string: urlQ)!

   URLSession.shared.dataTask(with: url) {(data,resp,error) in
            do {
                if let d = data {
                    print(data)
                    /*
                    let decodedLists = try JSONDecoder().decode([Weather].self,from: d)
                    DispatchQueue.main.async {
                        self.metroTimes = decodedLists

                    }
                    */
                }else {
                    print("No Data")
                }
            } catch {
                print ("Error")
                print(error)

            }

        }.resume()
}

但是会引发错误： “致命错误：解开可选值时意外发现nil：”

将文件解析为url字符串的正确方法是什么？