How to retrieve data from json response - ios

Question

I am trying to get data from json response, and the response format is mentioning below. I want to fetch "recipient" dictionary, and need to show in table.each cell contains name and unique id and image. How to get this dictionary to story in local dictionary?
{
"success": 1,
"status": 200,
"data": {
"chat": [
{
"id": 5,
"status": 0,
"created_at": "2019-02-19 13:29:15",
"updated_at": "2019-02-19 13:29:15",
"recipient": {
"id": 5,
"unique_id": "10004",
"name": "Pandu",
"avatar": "https://www.planetzoom.co.in/img/default_avatar_female.png"
},
"conversation": {
"id": 67,
"chat_id": 5,
"user_id": 4,
"type": 0,
"message": "I have sent a msg now",
"status": 0,
"created_at": "2019-02-26 04:02:20"
}
},
{
"id": 3,
"status": 0,
"created_at": "2019-02-19 13:17:49",
"updated_at": "2019-02-19 13:17:49",
"recipient": {
"id": 8,
"unique_id": "10007",
"name": "Mahitha",
"avatar": "https://www.planetzoom.co.in/storage/user/avatar/cZt9yQlBzIEewOdQ1lYZhl3dFiOv2k3bxG7HLOzR.jpeg"
},
"conversation": {
"id": 57,
"chat_id": 3,
"user_id": 4,
"type": 0,
"message": "Hi",
"status": 0,
"created_at": "2019-02-24 13:04:29"
}
},
{
"id": 2,
"status": 0,
"created_at": "2019-02-19 07:59:05",
"updated_at": "2019-02-19 07:59:05",
"recipient": {
"id": 1,
"unique_id": "1111",
"name": "Angadi World Tech",
"avatar": "https://www.planetzoom.co.in/storage/user/avatar/NlVzdUAfmLfIG9677szYZz7NkWyY4ULHAqnlCiiV.png"
},
"conversation": {
"id": 21,
"chat_id": 2,
"user_id": 4,
"type": 0,
"message": "Hi\\uD83D\\uDE0A",
"status": 0,
"created_at": "2019-02-21 10:35:26"
}
}
]
}
}

Answer 1

The best way to decode json in my opinion is to use Codable
I've created a few structs to represent the data and to decode it, please note this json wasn't valid so have had to wrap it in {}
Here's the json:
let jsonString = """
{
"chat": [
{
"id": 12,
"status": 0,
"created_at": "2019-02-22 04:57:12",
"updated_at": "2019-02-22 04:57:12",
"recipient": {
"id": 26,
"unique_id": "10024",
"name": "Kaverinew",
"avatar": "https://www.planetzoom.co.in/storage/user/avatar/1PyI4ceM3zPsG1fxbfatktWUT75sOE2Ttah8ctIp.png"
},
"conversation": {
"id": 65,
"chat_id": 12,
"user_id": 4,
"type": 1,
"message": "https://www.planetzoom.co.in/storage/chat/message/e759KWdSBegwXslAoS2xst0lohbbjNZMdpVnbxQG.png",
"status": 0,
"created_at": "2019-02-25 15:39:24"
}
},
{
"id": 6,
"status": 0,
"created_at": "2019-02-20 07:16:35",
"updated_at": "2019-02-20 07:16:35",
"recipient": {
"id": 7,
"unique_id": "10006",
"name": "Hema",
"avatar": "https://www.planetzoom.co.in/img/default_avatar_female.png"
},
"conversation": {
"id": 44,
"chat_id": 6,
"user_id": 4,
"type": 1,
"message": "https://www.planetzoom.co.in/storage/chat/message/qJjOtCRcBKBuq3UKaKVuVOEIQhaVPeJr3Bd4NoLo.png",
"status": 0,
"created_at": "2019-02-22 10:17:49"
}
}
]
}
Here are the structs:
struct Recipient: Codable {
var identifier: Int
var unique_id: Int
var name: String
var avatar: String
enum CodingKeys: String, CodingKey {
case identifier = "id"
case unique_id = "unique_id"
case name = "name"
case avatar = "avatar"
}
}
struct Conversation: Codable {
var identifier: Int
var chat_id: Int
var user_id: Int
var conversationType: Int
var message: String
var status: Int
var created_at: String
enum CodingKeys: String, CodingKey {
case identifier = "id"
case chat_id = "chat_id"
case user_id = "user_id"
case conversationType = "type"
case message = "message"
case status = "status"
case created_at = "created_at"
}
}
struct Chat: Codable {
var identifier: Int
var status: Int
var created_at: String
var updated_at: String
enum CodingKeys: String, CodingKey {
case identifier = "id"
case status = "status"
case created_at = "created_at"
case updated_at = "updated_at"
}
}
struct RootObject: Codable {
var chats: [Chat]
enum CodingKeys: String, CodingKey {
case chats = "chat"
}
}
And here is how you decode it:
if let jsonData = jsonString.data(using: .utf8) {
do {
let root = try JSONDecoder().decode(RootObject.self, from: jsonData)
} catch {
print(error)
}
}

Answer 2

Assuming you already have a Data object representing your JSON you can use JSONSerialization to convert it to concrete Swift object. Once that is done you simply need to go step by step and extract the data. Something like the following should work nicely:
func retrieveRecipients(jsonData: Data?) throws -> [[String: Any]] {
guard let data = jsonData else { throw NSError(domain: "Parsing Recipients", code: 404, userInfo: ["dev_message": "Null JSON data inserted"]) }
guard let parsedJSON = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) else { throw NSError(domain: "Parsing Recipients", code: 500, userInfo: ["dev_message": "Data could not be parsed as JSON"]) }
guard let object = parsedJSON as? [String: Any] else { throw NSError(domain: "Parsing Recipients", code: 500, userInfo: ["dev_message": "Parsed JSON is not a dictionary"]) }
guard let items = object["chat"] as? [[String: Any]] else { throw NSError(domain: "Parsing Recipients", code: 404, userInfo: ["dev_message": "JSON is missing \"chat\" array"]) }
return items.compactMap { $0["recipient"] as? [String: Any] }
}
This is all the safety enabled. Otherwise you could do it very shortly:
func retreiveRecipientsStrict(jsonData: Data?) -> [[String: Any]] {
return ((try! JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! [String: Any])["chat"] as! [[String: Any]]).compactMap { $0["recipient"] as? [String: Any] }
}
But this will crash if there is a mistake and it will be extremely hard to debug what went wrong.