iOS objectmapper, mapping json with array

Question

I have a simple question: how to convert such a json response to object with usage of Hearst-DD/ObjectMapper

{
   "errors": [
      {
         "code": "404",
         "message": "Wrong id"
      }
    ]
}

With swiftyJson i do

json["errors"][0]["code"]

but how to do it with objectmapper ? i tried this:

map["errors.code"]

and it does not work

EDIT: i did Error and ErrorResponse clasess like suggested, now:

//...
    let fullAddress = mainAddress + additionalAddr
    var parameters = ["email":email]

    manager.GET( fullAddress,
        parameters: parameters,
        success: { (operation: AFHTTPRequestOperation!,responseObject: AnyObject!) in
            //here is success, i got it done with user mapping
            callback(success: true)
        },
        failure: { (operation: AFHTTPRequestOperation!,error: NSError!) in

            let errorResponse = Mapper<ErrorResponse>().map(operation.responseString!)


            println(errorResponse!) //this prints: MyApp.ErrorResponse
            println(errorResponse?.errors!) //this prints: Optional([MyApp.Error]) 
            println(errorResponse?.errors![0]) //this prints:Optional(MyApp.Error)
            println(errorResponse?.errors![0].code) //<- this is nil :(
           // how to get the code mapped ?
            callback(success: false)
     })
}

it gives type of expression is amigous without more context. — Mansuu....
– Mansuu...., Commented Jul 3, 2017 at 14:38

Marcio Duarte · Accepted Answer · 2015-08-04 11:29:08Z

4

Your code doesn't work because the property errors is an array, and ObjectMapper try to convert it to an object.

For the JSON you have provided, the correct answer is as follow:

class Error: Mappable, Printable {
    var code: String?
    var message: String?

    init() {}

    class func newInstance() -> Mappable {
        return Error()
    }

    func mapping(map: Map) {
        self.code <- map["code"]
        self.message <- map["message"]
    }

    var description: String {
        get {
            return Mapper().toJSONString(self, prettyPrint: false)!
        }
    }
}

class ErrorResponse: Mappable, Printable {
    var errors: [Error]?

    init () {}

    class func newInstance() -> Mappable {
        return ErrorResponse()
    }

    func mapping(map: Map) {
        self.errors <- map["errors"]
    }

    var description: String {
        get {
            return Mapper().toJSONString(self, prettyPrint: false)!
        }
    }
}

Test:

    let json = "{\"errors\": [{\"code\": \"404\",\"message\": \"Wrong id\"}]}"

    let errorResponse = Mapper<ErrorResponse>().map(json)

    println("errorResponse: \(errorResponse?.description)")

    if let errors = errorResponse?.errors {
        println("errors: \(errors.description)")
        println("errors[0] \(errors[0])")
        println("errors[0].code \(errors[0].code)")
        println("errors.first!.message \(errors.first!.message)")
    }

Output:

errorResponse: Optional("{\"errors\":[{\"message\":\"Wrong id\",\"code\":\"404\"}]}")
errors: [{"message":"Wrong id","code":"404"}]
errors[0] {"message":"Wrong id","code":"404"}
errors[0].code Optional("404")
errors.first!.message Optional("Wrong id")

edited Aug 4, 2015 at 11:29

answered Aug 3, 2015 at 19:54

Marcio Duarte

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4 Comments

Ammo Over a year ago

It partially works: let errorResponse = Mapper<ErrorResponse>().map(operation.responseString!), then i get object of ErrorResponse, with array of [Error] object as you said. However when i do something like that errorResponse.errors.first.code - then it says nil. Shall i do some additional mapping ?

Marcio Duarte Over a year ago

@Ammo it works for me, btw I added a test to prove that it works

Marcio Duarte Over a year ago

@Ammo I tested your code with println(errorResponse?.errors![0].code) and it works. I think that the response code is nil, or you are missing something

Ammo Over a year ago

yeah thank you for the help, the problem with code was that json was actually like that (code is not passed as a string) : "errors": [ { "code": 404, "message": "Wrong id" } ]

Community · Accepted Answer · 2020-06-20 09:12:55Z

0

Should only pass the JSON-String and not a String you hand wrote to the map function.

From the README:

Once your class implements Mappable, the Mapper class handles everything else for you:

Convert a JSON string to a model object:

let user = Mapper<User>().map(JSONString)

So your scenario could be:

let error = Mapper<Error>().map(json)

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Aug 3, 2015 at 18:58

ezcoding

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