如何正确调试错误消息
Error Domain=NSCocoaErrorDomain Code=3840 "Invalid value around character 0." UserInfo={NSDebugDescription=Invalid value around character 0.}
我在不同的场景中看到这种情况发生,但我总是很难找到真正的原因。 在上面的例子中,我有以下 url,并返回 JSON 响应:
http://SERVERIP/v1/aeds&latitude=48.1848308444472&longitude=11.2527083605633
通过 Postman 进行服务器响应
{
"data": [
{
"deviceReference": "D200",
"owner": "Owner 200",
"latitude": "48.185240",
"longitude": "11.258890",
"street": "StreetName",
"featureTypeId": "1"
},
{
"deviceReference": "D300",
"owner": "Owner 300",
"latitude": "48.179290",
"longitude": "11.253350",
"street": "StreetName",
"featureTypeId": "1"
},
{
"deviceReference": "D100",
"owner": "Owner 100",
"latitude": "48.176226",
"longitude": "11.238890",
"street": "StreetName",
"featureTypeId": "1"
}
],
"meta": {
"Heading 1": "H1",
"Heading 2": "H2"
}
}
在我看来,json 已正确返回,但在通过 Alamofire 调用 URL 并处理它时,我仍然收到消息。
func getAEDInRange(latitude: Double, longitude: Double, completionHandler: (Result<[AED], NSError>) -> Void) {
Alamofire.request(Router.GetAEDInRange("?latitude=\(latitude)&longitude=\(longitude)")).responseArray { (response: Response<[AED], NSError>) -> Void in
print(response.result)
}
}
responseArray方法
public func responseArray<T: ResponseJSONObjectSerializable>(completionHandler: Response<[T], NSError> -> Void) -> Self {
let serializer = ResponseSerializer<[T], NSError> { request, response, data, error in
guard error == nil else {
return .Failure(error!)
}
guard let responseData = data else {
let failureReason = "Array could not be serialized because input data was nil."
let error = Error.errorWithCode(.DataSerializationFailed, failureReason: failureReason)
return .Failure(error)
}
let JSONResponseSerializer = Request.JSONResponseSerializer(options: .AllowFragments)
let result = JSONResponseSerializer.serializeResponse(request, response, responseData, error)
switch result {
case .Success(let value):
let json = SwiftyJSON.JSON(value)
// Get Data content of JSON
let jsonData = json["data"]
var objects: [T] = []
for (_, item) in jsonData {
if let object = T(json: item) {
objects.append(object)
}
}
return .Success(objects)
case .Failure(let error):
return .Failure(error)
}
}
return response(responseSerializer: serializer, completionHandler: completionHandler)
}
浏览器中返回的文字 URL:
{"data":[{"deviceReference":"D200","owner":"Owner 200","latitude":"48.185240","longitude":"11.258890","street":"StreetName","featureTypeId":"1"},{"deviceReference":"D300","owner":"Owner 300","latitude":"48.179290","longitude":"11.253350","street":"StreetName","featureTypeId":"1"},{"deviceReference":"D100","owner":"Owner 100","latitude":"48.176226","longitude":"11.238890","street":"StreetName","featureTypeId":"1"}],"meta":{"Heading 1":"H1","Heading 2":"H2"}}
最佳答案
如果您的 JSON 文档看起来不错,但无法解析(“字符 0 周围的错误”),则原因有两种明显的可能性:一是看起来不错的 JSON 文档不是您想要的文档正在尝试解析。第二,看起来不错,但其实并不好。例如,如果数据中有零字节会转换为不可见字符。
当错误发生时,将 NSData 的第一个字节记录为字节并检查实际情况。并在错误发生的确切时间记录转换为字符串的解析数据。
将AllowFragments 作为参数传递是无意义的。你并不期待一个片段。您不知道如何处理片段。如果有片段,那对您来说就是一个错误。那么为什么允许呢?充其量它会导致困惑(因为解析的响应现在可以像通常一样是字典或数组,但也可以是数字、字符串或 null)。
BOM(字节顺序标记)实际上允许出现在文档的开头,但不能出现在文档内部 - 如果文档中间出现错误,则需要查找该内容。 “字节 0 处的错误”通常是零字节。
关于JSON 字符 0 周围值无效调试,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35536024/