I have a json response like this
{
"name":"test",
"params":{
"param1":"testA",
"param2":4055,
"param3":9593.34959,
"question":"is this is a test?",
"anything":"testing?",
"random":true
},
"price":103.3
}
My codable struct looks like this
struct:Codable {
var name:String
var params:[String:String]?
var price:Double
}
I have set params to optional because sometimes there are no params but a lot of times there are and codable has an issue because I don't know what types the values in the params dictionary are. I don't even know what the keys are sometimes. I just want to parse them as a dictionary of keys and values with values of type Bool, Int, Double, or String. so a dict like this
let params = ["paramA":1, "param2":"test", "param3":true]
or in the case of the above json this:
let params = ["param1":"testA", "param2":4055, "param3": 9593.34959, "question":"is this is a test?", "anything":"testing?", "random":true]
I am pretty sure I have to create a custom decoder but not exactly sure how to do it.
In your case it's easier to decode json manually like so:
public enum SerializationError: Error {
case wrongRootElement(String)
case missing(String)
case invalid(String, Any)
}
struct YourStruct {
var name:String
var params:[String: String]?
var price:Double
}
extension YourStruct {
public init(json: Any) throws {
guard let jsonDict = json as? [String: Any] else {
throw SerializationError.wrongRootElement("Expected json dictionary not \(json)")
}
guard let name = jsonDict["name"] as? String else {
throw SerializationError.missing("name")
}
let params = jsonDict["params"] as? [String: Any]
let paramsStrs = params?.reduce(into: [String: String]()) { (result, keyValue) in
result[keyValue.key] = String(describing: keyValue.value)
}
guard let price = jsonDict["price"] as? Double else {
throw SerializationError.missing("price")
}
self.init(name: name, params: paramsStrs, price: price)
}
}
let anyYourStruct = try? JSONSerialization.jsonObject(with: jsonData, options: [])
let yourStruct = try? YourStruct(json: anyYourStruct)
Related
I am trying to decode data from a Firebase DataSnapshot so that it can be decoded using JSONDecoder.
I can decode this data fine when I use a URL to access it with a network request (obtaining a Data object).
However, I want to use the Firebase API to directly obtain the data, using observeSingleEvent as described on this page.
But, when I do this, I cannot seem to convert the result into a Data object, which I need to use JSONDecoder.
Is it possible to do the new style of JSON decoding with a DataSnapshot? How is it possible? I can't seem to figure it out.
I have created a library called CodableFirebase that provides Encoders and Decoders that are designed specifically for Firebase.
So for the example above:
import Firebase
import CodableFirebase
let item: GroceryItem = // here you will create an instance of GroceryItem
let data = try! FirebaseEncoder().encode(item)
Database.database().reference().child("pathToGraceryItem").setValue(data)
And here's how you will read the same data:
Database.database().reference().child("pathToGraceryItem").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value else { return }
do {
let item = try FirebaseDecoder().decode(GroceryItem.self, from: value)
print(item)
} catch let error {
print(error)
}
})
I've converted Firebase Snapshots using JSONDecoder by converting snapshots back to JSON in Data format. Your struct needs to conform to Decodable or Codable. I've done this with SwiftyJSON but this example is using JSONSerialization and it still works.
JSONSnapshotPotatoes {
"name": "Potatoes",
"price": 5,
}
JSONSnapshotChicken {
"name": "Chicken",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool? //Use optionals for keys that may or may not exist
}
Database.database().reference().child("grocery_item").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value as? [String: Any] else { return }
do {
let jsonData = try JSONSerialization.data(withJSONObject: value, options: [])
let groceryItem = try JSONDecoder().decode(GroceryItem.self, from: jsonData)
print(groceryItem)
} catch let error {
print(error)
}
})
Please note that if your JSON keys are not the same as your Decodable struct. You'll need to use CodingKeys. Example:
JSONSnapshotSpinach {
"title": "Spinach",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool?
enum CodingKeys: String, CodingKey {
case name = "title"
case price
case onSale
}
}
You can find more information on this using Apple Docs here.
No. Firebase returns a FIRDataSnapshot that can't be decodable. You can use this structure however, which is pretty simple and easy to understand:
struct GroceryItem {
let key: String
let name: String
let addedByUser: String
let ref: FIRDatabaseReference?
var completed: Bool
init(name: String, addedByUser: String, completed: Bool, key: String = "") {
self.key = key
self.name = name
self.addedByUser = addedByUser
self.completed = completed
self.ref = nil
}
init(snapshot: FIRDataSnapshot) {
key = snapshot.key
let snapshotValue = snapshot.value as! [String: AnyObject]
name = snapshotValue["name"] as! String
addedByUser = snapshotValue["addedByUser"] as! String
completed = snapshotValue["completed"] as! Bool
ref = snapshot.ref
}
func toAnyObject() -> Any {
return [
"name": name,
"addedByUser": addedByUser,
"completed": completed
]
}
}
And use toAnyObject() to save your item:
let groceryItemRef = ref.child("items")
groceryItemRef.setValue(groceryItem.toAnyObject())
Source: https://www.raywenderlich.com/139322/firebase-tutorial-getting-started-2
Or you can use this solution for children
extension DatabaseReference {
func makeSimpleRequest<U: Decodable>(completion: #escaping (U) -> Void) {
self.observeSingleEvent(of: .value, with: { snapshot in
guard let object = snapshot.children.allObjects as? [DataSnapshot] else { return }
let dict = object.compactMap { $0.value as? [String: Any] }
do {
let jsonData = try JSONSerialization.data(withJSONObject: dict, options: [])
let parsedObjects = try JSONDecoder().decode(U.self, from: jsonData)
completion(parsedObjects)
} catch let error {
print(error)
}
})
}
}
and use
self.refPriceStatistics.child(productId).makeSimpleRequest { (parsedArray: [YourArray]) in
callback(parsedArray)
}
If your data type is Codable you can use the following solution to decode directly. You do not need any plugin. I used the solution for Cloud Firestore.
import Firebase
import FirebaseFirestoreSwift
let db = Firestore.firestore()
let query = db.collection("CollectionName")
.whereField("id", isEqualTo: "123")
guard let documents = snapshot?.documents, error == nil else {
return
}
if let document = documents.first {
do {
let decodedData = try document.data(as: ModelClass.self)
// ModelClass a Codable Class
}
catch let error {
//
}
}
You can convert the value returned by Firebase to Data, and then decode that.
Add this extension to your project:
extension Collection {
//Designed for use with Dictionary and Array types
var jsonData: Data? {
return try? JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
}
}
Then use it to convert the value of the observed snapshot into data, which can then be decoded:
yourRef.observe(.value) { (snapshot) in
guard snapshot.exists(),
let value = snapshot.value as? [String],
let data = value.jsonData else {
return
}
//cast to expected type
do {
let yourNewObject = try JSONDecoder().decode([YourClass].self, from: data)
} catch let decodeError {
print("decodable error")
}
}
You can use this library CodableFirebase or the following extension can be helpful.
extension JSONDecoder {
func decode<T>(_ type: T.Type, from value: Any) throws -> T where T : Decodable {
do {
let data = try JSONSerialization.data(withJSONObject: value, options: .prettyPrinted)
let decoded = try decode(type, from: data)
return decoded
} catch {
throw error
}
}
I am trying to decode data from a Firebase DataSnapshot so that it can be decoded using JSONDecoder.
I can decode this data fine when I use a URL to access it with a network request (obtaining a Data object).
However, I want to use the Firebase API to directly obtain the data, using observeSingleEvent as described on this page.
But, when I do this, I cannot seem to convert the result into a Data object, which I need to use JSONDecoder.
Is it possible to do the new style of JSON decoding with a DataSnapshot? How is it possible? I can't seem to figure it out.
I have created a library called CodableFirebase that provides Encoders and Decoders that are designed specifically for Firebase.
So for the example above:
import Firebase
import CodableFirebase
let item: GroceryItem = // here you will create an instance of GroceryItem
let data = try! FirebaseEncoder().encode(item)
Database.database().reference().child("pathToGraceryItem").setValue(data)
And here's how you will read the same data:
Database.database().reference().child("pathToGraceryItem").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value else { return }
do {
let item = try FirebaseDecoder().decode(GroceryItem.self, from: value)
print(item)
} catch let error {
print(error)
}
})
I've converted Firebase Snapshots using JSONDecoder by converting snapshots back to JSON in Data format. Your struct needs to conform to Decodable or Codable. I've done this with SwiftyJSON but this example is using JSONSerialization and it still works.
JSONSnapshotPotatoes {
"name": "Potatoes",
"price": 5,
}
JSONSnapshotChicken {
"name": "Chicken",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool? //Use optionals for keys that may or may not exist
}
Database.database().reference().child("grocery_item").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value as? [String: Any] else { return }
do {
let jsonData = try JSONSerialization.data(withJSONObject: value, options: [])
let groceryItem = try JSONDecoder().decode(GroceryItem.self, from: jsonData)
print(groceryItem)
} catch let error {
print(error)
}
})
Please note that if your JSON keys are not the same as your Decodable struct. You'll need to use CodingKeys. Example:
JSONSnapshotSpinach {
"title": "Spinach",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool?
enum CodingKeys: String, CodingKey {
case name = "title"
case price
case onSale
}
}
You can find more information on this using Apple Docs here.
No. Firebase returns a FIRDataSnapshot that can't be decodable. You can use this structure however, which is pretty simple and easy to understand:
struct GroceryItem {
let key: String
let name: String
let addedByUser: String
let ref: FIRDatabaseReference?
var completed: Bool
init(name: String, addedByUser: String, completed: Bool, key: String = "") {
self.key = key
self.name = name
self.addedByUser = addedByUser
self.completed = completed
self.ref = nil
}
init(snapshot: FIRDataSnapshot) {
key = snapshot.key
let snapshotValue = snapshot.value as! [String: AnyObject]
name = snapshotValue["name"] as! String
addedByUser = snapshotValue["addedByUser"] as! String
completed = snapshotValue["completed"] as! Bool
ref = snapshot.ref
}
func toAnyObject() -> Any {
return [
"name": name,
"addedByUser": addedByUser,
"completed": completed
]
}
}
And use toAnyObject() to save your item:
let groceryItemRef = ref.child("items")
groceryItemRef.setValue(groceryItem.toAnyObject())
Source: https://www.raywenderlich.com/139322/firebase-tutorial-getting-started-2
Or you can use this solution for children
extension DatabaseReference {
func makeSimpleRequest<U: Decodable>(completion: #escaping (U) -> Void) {
self.observeSingleEvent(of: .value, with: { snapshot in
guard let object = snapshot.children.allObjects as? [DataSnapshot] else { return }
let dict = object.compactMap { $0.value as? [String: Any] }
do {
let jsonData = try JSONSerialization.data(withJSONObject: dict, options: [])
let parsedObjects = try JSONDecoder().decode(U.self, from: jsonData)
completion(parsedObjects)
} catch let error {
print(error)
}
})
}
}
and use
self.refPriceStatistics.child(productId).makeSimpleRequest { (parsedArray: [YourArray]) in
callback(parsedArray)
}
If your data type is Codable you can use the following solution to decode directly. You do not need any plugin. I used the solution for Cloud Firestore.
import Firebase
import FirebaseFirestoreSwift
let db = Firestore.firestore()
let query = db.collection("CollectionName")
.whereField("id", isEqualTo: "123")
guard let documents = snapshot?.documents, error == nil else {
return
}
if let document = documents.first {
do {
let decodedData = try document.data(as: ModelClass.self)
// ModelClass a Codable Class
}
catch let error {
//
}
}
You can convert the value returned by Firebase to Data, and then decode that.
Add this extension to your project:
extension Collection {
//Designed for use with Dictionary and Array types
var jsonData: Data? {
return try? JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
}
}
Then use it to convert the value of the observed snapshot into data, which can then be decoded:
yourRef.observe(.value) { (snapshot) in
guard snapshot.exists(),
let value = snapshot.value as? [String],
let data = value.jsonData else {
return
}
//cast to expected type
do {
let yourNewObject = try JSONDecoder().decode([YourClass].self, from: data)
} catch let decodeError {
print("decodable error")
}
}
You can use this library CodableFirebase or the following extension can be helpful.
extension JSONDecoder {
func decode<T>(_ type: T.Type, from value: Any) throws -> T where T : Decodable {
do {
let data = try JSONSerialization.data(withJSONObject: value, options: .prettyPrinted)
let decoded = try decode(type, from: data)
return decoded
} catch {
throw error
}
}
I am trying to parse my json data in swift 3.0. I am using Alamofire 4.0+
Here is my json
{
"token":
"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1MDQ0MjgzNzgxMTF9.CNonyvtQbRgaqqkdPO5KwqpVaUmlGrpaTqlBxmvaX80",
"expires": 1504428378111,
"user":
[{"user_id":13,"user_first_name":"Himanshu","user_last_name":"Srivastava","full_name":"Himanshu Srivastava"}]
}
Here is my model class to hold these values
import Foundation
import ObjectMapper
class LoginResult:Mappable{
var token:String?
var expires:Double?
var users:[[String:Any]]?
required init?(map:Map){
}
func mapping(map:Map)->Void{
self.token <- map["token"]
self.expires <- map["expires"]
self.users <- map["user"]
}
}
None of the solution available on internet worked for me. How can I parse this json and map to the model class?
Any help here?
I was mistaken, the value for key user is indeed a regular array.
This is a solution without a third party mapper and with an extra User struct (by the way the value for key expires is an Int rather than Double).
Assuming the user data comes from a database which always sends all fields the user keys are forced unwrapped. If this is not the case use optional binding also for the user data:
struct User {
let firstName : String
let lastName : String
let fullName : String
let userID : Int
}
class LoginResult {
let token : String
let expires : Int
var users = [User]()
init(json : [String:Any]) {
self.token = json["token"] as? String ?? ""
self.expires = json["expires"] as? Int ?? 0
if let users = json["user"] as? [[String:Any]] {
self.users = users.map { User(firstName: $0["user_first_name"] as! String,
lastName: $0["user_last_name"] as! String,
fullName: $0["full_name"] as! String,
userID: $0["user_id"] as! Int)
}
}
}
}
let json = "{\"token\":\"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1MDQ0MjgzNzgxMTF9.CNonyvtQbRgaqqkdPO5KwqpVaUmlGrpaTqlBxmvaX80\",\"expires\":504428378111,\"user\":[{\"user_id\":13,\"user_first_name\":\"Himanshu\",\"user_last_name\":\"Srivastava\",\"full_name\":\"Himanshu Srivastava\"}]}"
let jsonData = json.data(using: .utf8)!
do {
if let userData = try JSONSerialization.jsonObject(with: jsonData) as? [String:Any] {
let loginResult = LoginResult(json: userData)
print(loginResult.users[0])
// do something with loginResult
}
} catch {
print(error)
}
Here is the answer with map replaced by dictionary. Don't forget to handle error or unwrap carefully :)
let str = "{\"token\": \"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1MDQ0MjgzNzgxMTF9.CNonyvtQbRgaqqkdPO5KwqpVaUmlGrpaTqlBxmvaX80\",\"expires\": 1504428378111,\"user\": [{\"user_id\":13,\"user_first_name\":\"Himanshu\",\"user_last_name\":\"Srivastava\",\"full_name\":\"Himanshu Srivastava\"}]}"
let data = str.data(using: .utf8)
do{
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? [String: Any]
//Pass this json into the following function
}catch let error{
}
func mapping(json:[String: Any]?)->Void{
self.token <- json?["token"] as? String
self.expires <- json?["expires"] as? Double
self.users <- json?["user"] as? [[String: Any]]
}
I currently developing an app which list user object by making an request to a webservice, which send a response in JSON in this format :
{
"0":
{
"id":"30",
"title":"galaxys6",
"price":"550",
"description":"neuf",
"addedDate":"2015-07-16 15:04:24",
"user_id":"2",
"user_name":"",
"user_zipCode":"69003",
"category_id":"1",
"category_label":"PHONE",
"subcategory_id":"1",
"subcategory_label":"Phone",
"picture":"",
"bdd":{},
"picture_url":"http:\/\/jdl-barreme-orange.dyndns.org\/WEBSERVICE\/pictures\/galaxy s6.JPG"
},
"1":
{
"id":"31",
"title":"iphone4",
"price":"570",
"description":"neuf",
"addedDate":"2015-07-16 15:14:54",
"user_id":"2",
"user_name":"",
"user_zipCode":"69003",
"category_id":"1",
"category_label":"PHONE",
"subcategory_id":"1",
"subcategory_label":"Phone",
"picture":"",
"bdd":{},
"picture_url":"http:\/\/jdl-barreme-orange.dyndns.org\/WEBSERVICE\/pictures\/iphone.JPG"
},
}
For each object my webservice create a dictionary (0;1;2;3....)
I search a method to retrieve for each dictionary the value title and price and put them in a tableView.
Code I used (tableviewcontroller) :
if let jsonData:NSDictionary = NSJSONSerialization.JSONObjectWithData(urlData!, options:NSJSONReadingOptions.MutableContainers , error: &error) as? NSDictionary{
// 4
if let resp = jsonData["1"] as? [NSDictionary] {
NSLog("%#", resp)
// 5
for item in resp {
repositories.append(Repository(jsonData: item))
}
repository controller :
class Repository {
var name: String?
var description: String?
var html_url: String?
init(jsonData: NSDictionary) {
self.name = jsonData["id"] as? String
self.description = jsonData["description"] as? String
self.html_url = jsonData["title"] as? String
}
}
But it doesn't work, I put a breakpoint, and xcode stop to interpret here :
if let resp = jsonData["1"] as? [NSDictionary] {
NSLog("%#", resp)
What am I doing wrong?
Thank you.
Here's how to get the title and price for your JSON:
if let json = NSJSONSerialization.JSONObjectWithData(urlData!, options: nil, error: nil) as? [String:AnyObject] {
for (_, value) in json {
if let dict = value as? [String:AnyObject] {
if let title = dict["title"] as? String {
println(title)
}
if let price = dict["price"] as? String {
println(price)
}
}
}
}
This can also be used to init your Repository classes if you want:
class Repository {
var name: String?
var description: String?
var html_url: String?
init(jsonData: [String:AnyObject]) {
self.name = jsonData["id"] as? String
self.description = jsonData["description"] as? String
self.html_url = jsonData["title"] as? String
}
}
var repos = [Repository]()
if let json = NSJSONSerialization.JSONObjectWithData(urlData!, options: nil, error: nil) as? [String:AnyObject] {
for (_, value) in json {
if let dict = value as? [String:AnyObject] {
let repo = Repository(jsonData: dict)
repos.append(repo)
}
}
}
for repo in repos {
println(repo.name)
println(repo.description)
println(repo.html_url)
}
In the loop I'm ignoring the key: for (_, value) in json but you can use it if needed of course:
for (key, value) in json {
println(key) // "1", "2", ...
// ...
}
UPDATE:
Following your comment asking how to use this answer if your data format is different: if you want an array of dictionaries, change the typecast of the NSJSONSerialization result to reflect that: [[String:AnyObject]]. Next you can iterate over your array to get each dictionary properties:
if let jsonArray = NSJSONSerialization.JSONObjectWithData(urlData!, options: nil, error: nil) as? [[String:AnyObject]] {
for dict in jsonArray {
if let title = dict["title"] as? String {
println(title)
}
}
}
You are making a mistake here
if let resp = jsonData["1"] as? [NSDictionary]
This should be a NSDictionary not [NSDictionary], (which would be an array of dictionaries).
Also this conditional block
if let reposArray = jsonData["items"] as? [NSDictionary]
will never be executed because jsonData does not contain a key "items".
I guess it is the [NSDictionary]
if let resp = jsonData["1"] as? [NSDictionary]
[NSDictionary] is array of NSDictionary same as Array<NSDictionary>
just remove the brackets [] and change to
if let resp = jsonData["1"] as? NSDictionary
I'm trying to parse a json but I have some difficulties with the data types and notably the AnyObject type + downcasting.
Let's consider the following json (it's an extract of a full json).
{ "weather":
[
{
"id":804,
"main":"Clouds",
"description":"overcast clouds",
"icon":"04d"
}
],
}
To me, the json can be described as follow :
- json: Dictionary of type [String: AnyObject] (or NSDictionary, so = [NSObject, AnyObject] in Xcode 6 b3)
- "weather": Array of type [AnyObject] (or NSArray)
- Dictionary of type [String: AnyObject] (or NSDictionary, so = [NSObject, AnyObject] in Xcode 6 b3)
My json is of type AnyObject! (I use JSONObjectWithData to get the JSON from a URL).
I then want to access the weather Dictionary. Here is the code I wrote.
var localError: NSError?
var json: AnyObject! = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &localError)
if let dict = json as? [String: AnyObject] {
if let weatherDictionary = dict["weather"] as? [AnyObject] {
// Do stuff with the weatherDictionary
}
}
Here is the error I got
Playground execution failed: error: <EXPR>:28:56: error: '[AnyObject]' is not a subtype of '(String, AnyObject)'
if let weatherDictionary = dict["weather"] as? [AnyObject] {
I don't understand why dict["weather"] is compared to a subtype of (String, AnyObject) and not AnyObject.
I declared my dictionary as [String: AnyObject], so I i access a value using the String key, I should have an AnyObject, no ?
If I use NSDictionary instead of [String: AnyObject], it works.
If I use NSArray instead of [AnyObject], it works.
- The Xcode 6 beta 3 release notes tell that "NSDictionary* is now imported from Objective-C APIs as [NSObject : AnyObject].".
- And the Swift book: "When you bridge from an NSArray object to a Swift array, the resulting array is of type [AnyObject]."
EDIT
I forgot to force unwrapping the dict["weather"]!.
if let dict = json as? [String: AnyObject] {
println(dict)
if let weatherDictionary = dict["weather"]! as? [AnyObject] {
println("\nWeather dictionary:\n\n\(weatherDictionary)")
if let descriptionString = weatherDictionary[0]["description"]! as? String {
println("\nDescription of the weather is: \(descriptionString)")
}
}
}
Note that we should double check for the existence of the first Optional.
if let dict = json as? [String: AnyObject] {
for key in ["weather", "traffic"] {
if let dictValue = dict[key] {
if let subArray = dictValue as? [AnyObject] {
println(subArray[0])
}
} else {
println("Key '\(key)' not found")
}
}
}
This works fine for me in the playground and in the terminal using env xcrun swift
UPDATED FOR SWIFT 4 AND CODABLE
Here is a Swift 4 example using the Codable protocol.
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
struct Weather: Codable {
let id: Int
let main: String
let description: String
let icon: String
}
struct Result: Codable {
let weather: [Weather]
}
do {
let weather = try JSONDecoder().decode(Result.self, from: jsonStr.data(using: .utf8)!)
print(weather)
}
catch {
print(error)
}
UPDATED FOR SWIFT 3.0
I have updated the code for Swift 3 and also showed how to wrap the parsed JSON into objects. Thanks for all the up votes!
import Foundation
struct Weather {
let id: Int
let main: String
let description: String
let icon: String
}
extension Weather {
init?(json: [String: Any]) {
guard
let id = json["id"] as? Int,
let main = json["main"] as? String,
let description = json["description"] as? String,
let icon = json["icon"] as? String
else { return nil }
self.id = id
self.main = main
self.description = description
self.icon = icon
}
}
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
enum JSONParseError: Error {
case notADictionary
case missingWeatherObjects
}
var data = jsonStr.data(using: String.Encoding.ascii, allowLossyConversion: false)
do {
var json = try JSONSerialization.jsonObject(with: data!, options: [])
guard let dict = json as? [String: Any] else { throw JSONParseError.notADictionary }
guard let weatherJSON = dict["weather"] as? [[String: Any]] else { throw JSONParseError.missingWeatherObjects }
let weather = weatherJSON.flatMap(Weather.init)
print(weather)
}
catch {
print(error)
}
-- Previous Answer --
import Foundation
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
var data = jsonStr.dataUsingEncoding(NSASCIIStringEncoding, allowLossyConversion: false)
var localError: NSError?
var json: AnyObject! = NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers, error: &localError)
if let dict = json as? [String: AnyObject] {
if let weather = dict["weather"] as? [AnyObject] {
for dict2 in weather {
let id = dict2["id"]
let main = dict2["main"]
let description = dict2["description"]
println(id)
println(main)
println(description)
}
}
}
Since I'm still getting up-votes for this answer, I figured I would revisit it for Swift 2.0:
import Foundation
var jsonStr = "{\"weather\":[{\"id\":804,\"main\":\"Clouds\",\"description\":\"overcast clouds\",\"icon\":\"04d\"}],}"
var data = jsonStr.dataUsingEncoding(NSASCIIStringEncoding, allowLossyConversion: false)
do {
var json = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers)
if let dict = json as? [String: AnyObject] {
if let weather = dict["weather"] as? [AnyObject] {
for dict2 in weather {
let id = dict2["id"] as? Int
let main = dict2["main"] as? String
let description = dict2["description"] as? String
print(id)
print(main)
print(description)
}
}
}
}
catch {
print(error)
}
The biggest difference is that the variable json is no longer an optional type and the do/try/catch syntax. I also went ahead and typed id, main, and description.
Try:
https://github.com/dankogai/swift-json
With it you can go like this:
let obj:[String:AnyObject] = [
"array": [JSON.null, false, 0, "", [], [:]],
"object":[
"null": JSON.null,
"bool": true,
"int": 42,
"double": 3.141592653589793,
"string": "a α\t弾\n𪚲",
"array": [],
"object": [:]
],
"url":"http://blog.livedoor.com/dankogai/"
]
let json = JSON(obj)
json.toString()
json["object"]["null"].asNull // NSNull()
json["object"]["bool"].asBool // true
json["object"]["int"].asInt // 42
json["object"]["double"].asDouble // 3.141592653589793
json["object"]["string"].asString // "a α\t弾\n𪚲"
json["array"][0].asNull // NSNull()
json["array"][1].asBool // false
json["array"][2].asInt // 0
json["array"][3].asString // ""
Using my library (https://github.com/isair/JSONHelper) you can do this with your json variable of type AnyObject:
var weathers = [Weather]() // If deserialization fails, JSONHelper just keeps the old value in a non-optional variable. This lets you assign default values like this.
if let jsonDictionary = json as? JSONDictionary { // JSONDictionary is an alias for [String: AnyObject]
weathers <-- jsonDictionary["weather"]
}
Had your array not been under the key "weather", your code would have been just this:
var weathers = [Weather]()
weathers <-- json
Or if you have a json string in your hands you can just pass it as well, instead of creating a JSON dictionary from the string first. The only setup you need to do is writing a Weather class or struct:
struct Weather: Deserializable {
var id: String?
var name: String?
var description: String?
var icon: String?
init(data: [String: AnyObject]) {
id <-- data["id"]
name <-- data["name"]
description <-- data["description"]
icon <-- data["icon"]
}
}