Encode/Decode JSON locally from documentDirectory - json

Question

I am fairly new to SWIFT and am trying to use data from a JSON file (financetoday.json) to populate a table and for the user to update and have the data stored on the device. The table has collapsing cells (using XIB) and each cell has an embedded UISlider to update the values. On my initial work, I have the table loading the JSON file successfully from the bundle, populating the table, and the slider changes each value. Now the hard part. In order to save/change the data I need to move the JSON file into the documentDirectory, then have any changes to the data from this file. Once the user starts the app for the first time, I no longer need to use the JSON file in the bundle, just the version in the documentDirectory. I have been unable to get table to read the JSON file in the documentDirectory. Any help would be appreciated.
Here is where I have added a method in AppDelegate to move the JSON file in the document Directory
// Move json file from bundle to documents folder
var finalDatabaseURL:String = String()
func copyDatabaseIfNeeded() {
let fileManager = FileManager.default
let documentsUrl = fileManager.urls(for: .documentDirectory,
in: .userDomainMask)
guard documentsUrl.count != 0 else {
return // Could not find documents URL
}
let finalDatabaseURL = documentsUrl.first!.appendingPathComponent("financetoday.json")
if !( (try? finalDatabaseURL.checkResourceIsReachable()) ?? false) {
print("DB does not exist in documents folder")
let documentsURL = Bundle.main.resourceURL?.appendingPathComponent("financetoday.json")
do {
try fileManager.copyItem(atPath: (documentsURL?.path)!, toPath: finalDatabaseURL.path)
} catch let error as NSError {
print("Couldn't copy file to final location! Error:\(error.description)")
}
} else {
print("Database file found at path: \(finalDatabaseURL.path)")
}
}
Then I added to applicationDidBecomeActive
self.copyDatabaseIfNeeded()
In my data model this is what it looks like loading JSON data from the bundle, but I need to change the code in method dataFromFile to use JSON file in documentDirectory...not the bundle. All my attempts to change results in a blank table. So for now I am pointing to the JSON in the bundle. Any help would be appreciated.
import Foundation
public func dataFromFile(_ filename: String) -> Data? {
#objc class TestClass: NSObject { }
let bundle = Bundle(for: TestClass.self)
if let path = bundle.path(forResource: filename, ofType: "json") {
return (try? Data(contentsOf: URL(fileURLWithPath: path)))
}
return nil
}
class Plan {
var yeardata: Int?
var incomedata = [Income]()
var expensedata = [Expense]()
var assetdata = [Asset]()
var liabilitydata = [Liability]()
var profiledata = [Profile]()
var assumptiondata = [Assumption]()
init?(data: Data) {
do {
if let json = try JSONSerialization.jsonObject(with: data) as? [String: Any], let myplan = json["data"] as? [String: Any] {
if let incomedata = myplan["incomedata"] as? [[String: Any]] {
self.incomedata = incomedata.map { Income(json: $0) }
}
if let expensedata = myplan["expensedata"] as? [[String: Any]] {
self.expensedata = expensedata.map { Expense(json: $0) }
}
if let assetdata = myplan["assetdata"] as? [[String: Any]] {
self.assetdata = assetdata.map { Asset(json: $0) }
}
if let liabilitydata = myplan["liabilitydata"] as? [[String: Any]] {
self.liabilitydata = liabilitydata.map { Liability(json: $0) }
}
if let profiledata = myplan["profiledata"] as? [[String: Any]] {
self.profiledata = profiledata.map { Profile(json: $0) }
}
if let assumptiondata = myplan["assumptiondata"] as? [[String: Any]] {
self.assumptiondata = assumptiondata.map { Assumption(json: $0) }
}
}
} catch {
print("Error deserializing JSON: \(error)")
return nil
}
}
}
class Income {
var key: String?
var value: Any?
init(json: [String: Any]) {
self.key = json["key"] as? String
self.value = json["value"] as Any
}
}
class Expense {
var key: String?
var value: Any?
init(json: [String: Any]) {
self.key = json["key"] as? String
self.value = json["value"] as Any
}
}
class Asset {
var key: String?
var value: Any?
init(json: [String: Any]) {
self.key = json["key"] as? String
self.value = json["value"] as Any
}
}
class Liability {
var key: String?
var value: Any?
init(json: [String: Any]) {
self.key = json["key"] as? String
self.value = json["value"] as Any
}
}
class Profile {
var key: String?
var value: Any?
init(json: [String: Any]) {
self.key = json["key"] as? String
self.value = json["value"] as Any
}
}
class Assumption {
var key: String?
var value: Any?
init(json: [String: Any]) {
self.key = json["key"] as? String
self.value = json["value"] as Any
}
}

Answer 1

This will read in the json. The dictionary conversion I am less familiar with because I have started using the Codable protocol which I highly recommend.
if let path = Bundle.main.path(forResource: "FileName", ofType: "json") {
do {
let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .alwaysMapped)
let jsonString = String(data: value, encoding: .utf8)
print("json as string: \(jsonString)")
let json = try JSONSerialization.data(withJSONObject: data, options: []) as? [String: Any]
print("json as dictionary: \(json)")
} catch let error {
print("parse error: \(error.localizedDescription)")
}
}
How to decode codable Data:
let decoder = JSONDecoder()
do {
let decodableJSON = try decoder.decode(ObjectConformingToCodable.self, from: data)
print(decodableJSON)
} catch let error {
print(error.localizedDescription)
}

Answer 2

not sure if this is relevant but could try:
let documentsDirectoryPathString = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!
let documentsDirectoryPath = NSURL(string: documentsDirectoryPathString)!
let jsonFilePath = documentsDirectoryPath.appendingPathComponent("test.json")
let fileManager = FileManager.default
var isDirectory: ObjCBool = false
// creating a .json file in the Documents folder
if fileManager.fileExists(atPath: (jsonFilePath?.absoluteString)!, isDirectory: &isDirectory) {
print("File exists")
}
I also found: JSONSaveLoad.swift on Gist:
https://gist.github.com/norsez/aa3f11c0e875526e5270e7791f3891fb
I'm sure there are other similar examples on Github