ios - Swift - 调用中参数 'host' 缺少参数

Question

这是我的代码:

func submitLacunaRequest (#module: String, method: String, parameters: AnyObject, completion: (responseObject: AnyObject!, error: NSError!) -> (Void)) -> NSURLSessionTask? {
        let session = NSURLSession.sharedSession()
        let url = NSURL(string: "https://us1.lacunaexpanse.com").URLByAppendingPathComponent(module)
        let request = NSMutableURLRequest(URL: url)
        request.HTTPMethod = "POST"
        request.setValue("application/json-rpc", forHTTPHeaderField: "Content-Type")

调用中缺少参数“host”的参数。它发生在这条线上。

 let url = NSURL(string: "https://us1.lacunaexpanse.com").URLByAppendingPathComponent(module)

有什么解决办法吗？

谢谢!

Answer 1

该错误具有误导性。问题不是缺少参数，而是您如何访问 NSURL。您要么必须添加一个 ? 来访问可选的，因为 NSURL 可以为 null，要么您解包它:

//First option:
let url = NSURL(string: "https://us1.lacunaexpanse.com")?.URLByAppendingPathComponent(module)

//Unwrapping
if let url = NSURL(string: "https://us1.lacunaexpanse.com")?.URLByAppendingPathComponent(module){
    let request = NSMutableURLRequest(URL: url)
    request.HTTPMethod = "POST"
    request.setValue("application/json-rpc", forHTTPHeaderField: "Content-Type")
}