Swift decode JSON with unknown keys - json

I have a JSON file in my app bundle that looks like this
{
"1": "cat",
"2": "dog",
"3": "elephant"
}
What I'd like is to be able to find the value for the "2" key for example ("dog").
I'm using this extension to decode the json file:
let config = Bundle.main.decode(Config.self, from: "config.json")
And I have this struct defined:
struct Config: Codable {
let id: String
let animal: String
}
But how do I find the animal name for the "2" key?

You seem to be trying to decode your JSON as if it were an array of your Config structs - that would look like this:
[
{
"id": "1",
"animal": "cat"
},
{
"id": "2",
"animal": "dog"
},
{
"id": "3",
"animal": "elephant"
}
]
But your data (config.json) isn't that, it's just a JSON dictionary of String keys with String values.
You can instead "decode" it as just a String: String dictionary like:
let dict = Bundle.main.decode([String: String].self, from: "config.json")
and then dict["2"] would indeed be an optional string, with a value of .some("dog")
Or perhaps you mean your JSON to be an array of Config's, if you change the contents of config.json file to the above, and then decode it with:
let config = Bundle.main.decode([Config].self, from: "config.json")
Then the animal with id of 2 would be, e.g.
config.first(where: { $0.id == "2" })?.animal

Related

Load JSON in SwiftUI with arbitrary keys

I have a pretty simple JSON file I would like to load into a SwiftUI project. The JSON file looks like this:
{
"all": ["foo", "bar", "baz", ...],
"4": ["asd", "qwe", ...],
"25": ["something", "another", ...],
...
"2": ["xxx", "yyy", ...]
}
Pretty simple, a dictionary where each value is a list of strings. The keys are "all" and then an arbitrary number of integers such as "1", "123" and so on. They must not be in order, they can be any number, and there may be any number of them. So I don't know before hand how many keys there are.
I have managed to get this JSON into a variable of type String. But now I am stuck with how to parse this so I can for example fetch the list at key "all", or check if the key "123" exists and if so get that list.
How do I do that in SwiftUI?
Oh, and by the way, the string are Unicode and contain special characters like åäö.
try this approach:
struct ContentView: View {
#State var dataList: [String:[String]] = [:]
var body: some View {
List(Array(dataList.keys), id: \.self) { key in
Section(header: Text(key).foregroundColor(.red).font(.headline)) {
if let values = dataList[key] {
ForEach(values, id: \.self) { item in
Text("\(item)")
}
}
}
}
.onAppear {
let json = """
{
"all": ["foo", "bar", "baz"],
"4": ["asd", "qwe"],
"25": ["something", "another"],
"2": ["xxx", "yyy", "åäö"],
"åäö": ["qwerty", "uiop", "dfghjkh"]
}
"""
if let data = json.data(using: .utf8) {
do {
self.dataList = try JSONDecoder().decode([String: [String]].self, from: data)
} catch {
print("decode error: \(error)")
}
}
}
}
}

Issue Parsing / Decoding JSON from API Endpoint Into Struct Object

I am writing a Swift 5.x app using Alamofire 5 to get a list of files from an API I wrote. The API returns the file list as a JSON Data object. I want to then get this data into a struct I created. I am not able to get this working. Here is an example JSON string that my server sends over when you hit the API endpoint:
[{
"ID": "0d37ee7a-39bf-4eca-b3ec-b3fe840500b5",
"Name": "File01.iso",
"Size": 6148
}, {
"ID": "656e0396-257d-4604-a85c-bdd0593290cd",
"Name": "File02.iso",
"Size": 224917843
}, {
"ID": "275fdf66-3584-4899-8fac-ee387afc2044",
"Name": "File04.iso",
"Size": 5549504
}, {
"ID": "1c73f857-56b5-475b-afe4-955c9d2d87fe",
"Name": "File05.iso",
"Size": 15476866871
}, {
"ID": "bfebbca2-49de-43d7-b5d0-3461b4793b62",
"Name": "File06.iso",
"Size": 37254264
}]
I created the following Data Model in swift to hold this:
struct Files: Decodable {
let root: [File]
}
struct File: Decodable, Identifiable {
var id: UUID
var name: String
var size: Int
}
enum CodingKeys: String, CodingKey {
case id = "ID"
case name = "Name"
case size = "Size"
}
Then I used Alamofire 5.x to call the API endpoint and attempt to decode the JSON and place it into the object in question:
func getPackageFilesJSON() {
AF.request("http://localhost:8080/api/v1/list/pkgs").responseDecodable(of: Files.self) { response in
guard let serverFiles = response.value else {
print("Error Decoding JSON")
return
}
let self.serverFilesList = serverFiles
}
}
This fails. If I debugPrint the response I get this for the result:
[Result]: failure(Alamofire.AFError.responseSerializationFailed(reason: Alamofire.AFError.ResponseSerializationFailureReason.decodingFailed(error: Swift.DecodingError.typeMismatch(Swift.Dictionary<Swift.String, Any>, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Dictionary<String, Any> but found an array instead.", underlyingError: nil)))))
I have never been great at creating these data models and decoding JSON into them. I am sure I am missing something silly. I am hopeful that someone more knowledgable than me, or a second set of eyes can help me get this working.
Thanks,
Ed
There is no key root in the JSON. The root object is an array
Delete
struct Files: Decodable {
let root: [File]
}
and decode
AF.request("http://localhost:8080/api/v1/list/pkgs").responseDecodable(of: [File].self) { response in ...
and move the CodingKeys enum into the File struct
struct File: Decodable, Identifiable {
var id: UUID
var name: String
var size: Int
enum CodingKeys: String, CodingKey {
case id = "ID"
case name = "Name"
case size = "Size"
}
}

Swift : How to create a dictionary dynamically from a json?

I'd like some advice from you. I would like to create a dictionary from a dynamic response fetch from an API and send that dictionary in an Alamofire POST request.
From what I have so far it's working but I'm not satisfied with what i've made and I think the code is really messy.
Here is an example of what I can receive
"content": {
"type": "form",
"fields": [
{
"type": "select",
"label": "Do you have your documents?",
"field": "user.has_docs",
"default": 0,
"choices": [
{
"value": 0,
"name": "Not yet"
},
{
"value": 1,
"name": "I do"
}
]
},
{
"type": "input",
"field": "user.date",
"label": "When do you arrive?",
}
]
}
After parsing the json with the Codable protocol, I have all my data in the Model Field
type: String
label: String
field: String
defaultValue: Int?
choice: [Choice]?
Choice
value: Int
name: String
So I want to create my dictionary and I want the following scheme :
{
"value": {
"user": {
"has_docs": 1,
"date": "29/07/2020"
}
}
}
The key named : "value" is always the same value, but the other one depends of the result from the API. the prefix of the field corresponding of "parent object" and the right part is the child.
Hard coding a dictionary in Swift is not that hard, I would do
let dict = [
"value": [
"user": [
"has_docs": 1,
"date": "29/07/2020"
]
]
]
But the troubles begin, at the attempt of creating a dictionary dynamically. Values inside user keep only the last one and replacing has_docs with date.
I have found a workaround with using flatmap and reduce but it only allows the type [String: String], unfortunately I need to write [String: Int] too in the dictionary.
here is a sample of the code
let flattenedDictionary = [key : dictionaries
.flatMap { $0 }
.reduce([String:String]()) { (dict, tuple) in
var nextDict = dict
nextDict.updateValue(tuple.1 as! String, forKey: tuple.0)
return nextDict
}]
parameters["value"] = flattenedDictionary
Here :
key = "user".
dictionaries = [["has_docs": 1], ["date": "29/07/2020"]]
Feel free to exchange if you need more informations
If you have any clue on how you could helping me, I'll highly appreciate, thanks for reading so far.
I hope I was very understandable.
Edit
From a general view : I'd like to create a dictionary dynamically
[String: [String: [String: Any]]]
A bit unclear if you have a [String: [String: [String: Any]]] or [String: [String: Any]] dictionary, but the concept of creating it dynamically would be rather similar.
var user: [String: Any] = [:]
user["has_docs"] = 1
user["date"] = Date()
let dict = ["value": user]

SWIFT 4 nested JSON Struct - Codable

I'm having issues creating a struct to parse JSON in Swift 4. I'm able to parse small JSONs and JSONDecoder seems to work fine. Just need help to create a struct to parse JSON like that:
{
"main": {
"solutions": [
{
"exersises": [
{
"book_title": "test",
"release_date": "2015-01-12T11:00",
"price": 100,
"additional": [
{
"item1": "test",
"item2": "test",
"number": 1
},
{
"item1": "test2",
"item2": "test2",
"number": 2
}
],
"availability": "Yes",
"item_id": 43534
}
]
}
]
}
}
What kind of struct do I need to get to value of book_title for example?
Its really easy. Your main probem is most likely root element. Let me get first layer or two for you.
let decoded = try JSONDecoder().decode(MainJSON.self, from: data)
class MainJSON: Codable {
var main:SolutionJSON?
}
class SolutionJSON: Codable {
var exercises:[ExercisesJSON]?
}
class ExercisesJSON: Codable {
var bookTitle: String?
var releaseDate: String?
var price: Double?
... etc
enum CodingKeys: String, CodingKey {
case bookTitle = "book_title"
case releaseDate = "release_date"
case price = "price"
}
}
ExerciseJSON also uses Codable interface which lets remap json properties into swift properties if they don't match. Hope this helps.
i prefer to give a general solution not only for this condition
it is very simple just download and run this MACOS APP from GITHUB
run it in your mac by XCODE and but your JSON in it,
it will make Models for any complex JSON
notes
1 if JSON keys have a capital character in the first it will be small
, so after copying model you need to change it like the JSON
2 if two JSON objects have the same structure and the same key names it will be only one model

How to parse JSON in Swift?

I have some JSON data that looks like this which I am trying to parse in Swift.
[
[
{
a: "1",
b: "2"
},
[
{
c: "3",
},
{
d: "4",
}
]
]
]
let json = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments)
if let myArray = json[0] as? [[AnyObject]] {
for myObject in myArray {
print("This works!\(myObject)")
}
}
However nothing I try seems to work - any help would be appreciated.
you can use SwiftyJSON - https://github.com/SwiftyJSON/SwiftyJSON
or create a class based on your JSON scheme try to parse with it.
like:
class object
{
let data = Array<subObject>()
}
class subObject
{
let subData = Array<Dictionary<AnyObject,AnyObject>>()
}
This snippet is not JSON. If it was JSON, the keys would be strings, like this:
[
[
{
"a": "1",
"b": "2"
},
[
{
"c": "3",
},
{
"d": "4",
}
]
]
]
And anyway in your screenshot we see that your JSON has already been parsed!
What you show in the image is not JSON either, but an array containing arrays and dictionaries...
But let's say your JSON is actually valid and the missing quotes are just a copy/paste problem.
Then to achieve your goal you have to cast the result of NSJSONSerialization to the correct JSON format, then you can access the inner objects.
Like this, for example:
do {
if let json = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [[AnyObject]] {
if let myArray = json.first {
for myObject in myArray {
print("This works!\(myObject)")
}
}
}
} catch let error as NSError {
print(error.localizedDescription)
}