Codable for json response getting an error while parsing

Question

After constructed the codable, getting an error.

"msg": {
        "success": [
            "Successfully logged in."
        ]
    },
    "messages": []
}

// Constructed the codable for the parsing response data

    struct Msg:Codable{
   let success: [String]?
    enum CodingKeys: String, CodingKey{
    case success = "succcess"
    }
    init (from decoder: Decoder)throws{
    let value = try decoder.container(keyedBy: CodingKeys.self)
    sucess = try values.decodeIfPresent([String].self, forKey: .success)
    }
   }

I got this error when doing codable

erro typeMismatch(Swift.Dictionary<swift.string, Any>. Swift.DecodingError.Context ( codingPath: [CodingKeys(StringValue:"msg", intValue:nil], debugDescription: Expected to decode Dictionary <String,Any> but found an array instead."underlyingError: nil))

How to resolve this part based on server response.

Your json is not an array which the error message clearly tells you, you need a top level struct for msg, `struct Root: Codable {let msg: Msg}` and then use that when decoding — Joakim Danielson, Aug 07 '20 at 11:35
Be aware that you can omit both `init` methods and also the CodingKeys. And this can’t be the real JSON because it cannot cause this error. And if you’re responsible for the backend consider a better data structure. — vadian, Aug 07 '20 at 12:43
Based on error description its says CodingKeys(StringValue:"msg", intValue:nil]. Never see any intValue to asign — kiran, Aug 07 '20 at 12:47
`intValue` is `nil` because the key cannot be represented by an Int. Anyway the error has nothing to do with `intValue`. — vadian, Aug 07 '20 at 12:51
@JoakimDanielson if forget to add { } the code inside. Its shows valid json! I do not have control on backend side. — kiran, Aug 07 '20 at 12:51
There is no error if you implement the solution below properly so revert your question to its first version and accept the answer below. _Edit: I did the revert for you_ — Joakim Danielson, Aug 07 '20 at 12:51

score 0 · Answer 1 · answered Aug 07 '20 at 11:50

0

This should work for you:

struct Msg: Codable {
    let success: [String]?
}

struct Response: Codable {
    let msg: Msg
}

let json = #"""
{
    "msg": {
        "success": [
            "Successfully logged in."
        ]
    },
    "messages": []
}
"""#

if let response = try? JSONDecoder().decode(Response.self, from: json.data(using: .utf8)!) {
    print(response.msg.success?.first) // Optional("Successfully logged in.")
}

answered Aug 07 '20 at 11:50

iUrii

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1

Always decode using `do-try-catch`. Using `try?` hides all possible errors. – pawello2222 Aug 07 '20 at 11:52

Codable for json response getting an error while parsing

1 Answers1