我想寫一個POST請求到我的本地服務器,這是我的函數:斯威夫特4可解:給定的數據是不是有效的JSON
@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()
}
這些都是用這裏的結構:
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
}
它能夠打印
JSON String : {"data":{"message":{"message":"Hi","timestamp":"2017-10-18 00:50:13","latitude":"1.1","longitude":"2.2"}}}
但一直顯示此錯誤:
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.})))
爲什麼它不是一個有效的JSON?
這裏是我的服務器的API POST請求文檔:
POST
/api/message
{
data: {
message: {
message: 「Hey, a new message!」,
timestamp: 2017-09-10 10:22:33,
latitude: 62.233589156441724,
longitude: 25.735066461654696
}
}
}
我已經做了相當長的一段谷歌搜索,但我在這裏卡住了很長的時間! 任何幫助表示讚賞!
我在Playground中運行了基本的解碼代碼,它工作正常。我可能會建議你將'Data'解碼爲'String'並打印出來,以確保你確切知道你想要解碼什麼,因爲如果它以'POST'開頭,那麼這就是你的問題 – MadProgrammer
打印接收到的數據: '在'decode'行之前打印(數據爲NSData)。第一個字節必須是「7B」。錯誤消息說,它不是。 – vadian
@vadian說什麼。你已經構思了這個問題,好像你認爲你構建數據的方式有問題。沒有。你得到的錯誤信息實際上是一個來自*解碼*一個JSON字符串到Swift對象。當它表示文本必須以數組或對象開頭時,這意味着該字符串必須分別以'['或'{'開頭。可能從服務器的響應不是JSON – JeremyP