ios - Swift 4 可解码 : The given data was not valid JSON

Question

我正在尝试向我的本地服务器写入一个 POST 请求，这是我的功能:

@IBAction func postButtonAction(_ sender: UIButton) {

    guard let url = URL(string:"http://localhost:443/api/message") else {return}
    var request = URLRequest(url: url)
    request.httpMethod = "POST"
    request.addValue("application/json", forHTTPHeaderField: "Content-Type")
    print("POSTED")

    let date : Date = Date()
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    let dateTime = dateFormatter.string(from: date)

    let newPost = MessageForPost(message: "Hi", timestamp: dateTime, latitude: "1.1", longitude: "2.2")
    let newData = DataForPost(message: newPost)
    let newPackage = PackageForPost(data: newData)

    do {
        let jsonBody = try JSONEncoder().encode(newPackage)
        request.httpBody = jsonBody
        print("jsonBody:",jsonBody)
        let jsonBodyString = String(data: jsonBody, encoding: .utf8)
        print("JSON String : ", jsonBodyString!)
    } catch let err  {
        print("jsonBody Error: ",err)
    }

    let session = URLSession.shared
    let task = session.dataTask(with: request){ (data,response,err) in

        guard let data = data else {return}

        do{
            let sendPost = try JSONDecoder().decode(PackageForPost.self, from: data)
            print("DATA:\(data)")
        }catch let err{

            print("Session Error: ",err)
        }
    }
    task.resume()
}

这些是这里使用的结构:

struct PackageForPost:Encodable, Decodable{
    let data: DataForPost
}

struct DataForPost:Encodable, Decodable{
    let message: MessageForPost
}

struct MessageForPost:Codable {
    let message: String
    let timestamp: String
    let latitude: String
    let longitude: String
}

它能够打印

JSON String :  {"data":{"message":{"message":"Hi","timestamp":"2017-10-18 00:50:13","latitude":"1.1","longitude":"2.2"}}}

但它一直显示这个错误:

Session Error: dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.})))

为什么它不是有效的 JSON？？？

这是我的服务器的 API POST 请求文档:

POST
/api/message

{
    data: {
        message: {

            message: “Hey, a new message!”,
            timestamp: 2017-09-10 10:22:33,
            latitude: 62.233589156441724,
            longitude: 25.735066461654696
        }
   } 
}

我已经进行了相当多的谷歌搜索，但我被困在这里很长时间了! 任何帮助表示赞赏!

Answer 1

很简单...我遇到了同样的问题。

看你的结构是解码和编码时间戳，纬度和经度，因为字符串和 JSON 是 Double 或 Floating 类型。

struct MessageForPost:Codable {
    let message: String
    let timestamp: String
    let latitude: String
    let longitude: String
}

这里是 JSON

{
    data: {
        message: {
            message: "Hey, a new message!",
            timestamp: 2017-09-10 10:22:33,
            latitude: 62.233589156441724,
            longitude: 25.735066461654696
        }
   } 
}

....我最后修复了它并且......它起作用了......

已编辑 使用相同的数据类型...