Swift JSONDecoder typeMismatch error
I'm trying to use JSONDecoder to convert a JSON to Structs in Swift, so I wrote all the Structs, revised them for hours, and it still gives me this error. I don't know if there is a way to see the line that gives this. I'll post my struct below and the Json File links right after.
The complete error description is:
typeMismatch(Swift.Dictionary<Swift.String, Any>, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Dictionary<String, Any> but found an array instead.", underlyingError: nil))
// Created by Breno Ramos on 28/12/17.
// Copyright © 2017 brenor2. All rights reserved.
//
import Foundation
struct Owner:Decodable {
let login : String?
let id : Double?
let avatar_url : String?
let gravatar_id : String?
let url : String?
let html_url : String?
let followers_url : String?
let following_url : String?
let gists_url : String?
let starred_url : String?
let subscriptions_url : String?
let organizations_url : String?
let repos_url : String?
let events_url : String?
let received_events_url : String?
let type : String?
let site_admin : Bool?
}
struct License:Decodable {
let key : String?
let name : String?
let spdx_id : String?
let url : String?
}
struct Repo:Decodable {
let id : Double?
let name : String?
let full_name : String?
let owner : Owner?
let `private` : Bool?
let html_url : String?
let description : String?
let fork : Bool?
let url : String?
let forks_url : String?
let keys_url : String?
let collaborators_url : String?
let teams_url : String?
let hooks_url : String?
let issue_events_url : String?
let events_url : String?
let assignees_url : String?
let branches_url : String?
let tags_url : String?
let blobs_url : String?
let git_tags_url : String?
let git_refs_url : String?
let trees_url : String?
let statuses_url : String?
let languages_url : String?
let stargazers_url : String?
let contributors_url : String?
let subscribers_url : String?
let subscription_url : String?
let commits_url : String?
let git_commits_url : String?
let comments_url : String?
let issue_comment_url : String?
let contents_url : String?
let compare_url : String?
let merges_url : String?
let archive_url : String?
let downloads_url : String?
let issues_url : String?
let pulls_url : String?
let milestones_url : String?
let notifications_url : String?
let labels_url : String?
let releases_url : String?
let deployments_url : String?
let created_at : String?
let updated_at : String?
let pushed_at : String?
let git_url : String?
let ssh_url : String?
let clone_url : String?
let svn_url : String?
let homepage : String?
let size : Double?
let stargazers_count : Double?
let watchers_count : Double?
let language : String?
let has_issues : Bool?
let has_projects : Bool?
let has_downloads : Bool?
let has_wiki : Bool?
let has_pages : Bool?
let forks_count : Double?
let mirror_url : String?
let archived : Bool?
let open_issues_count : Double?
let license : License?
let forks : Double?
let open_issues : Double?
let topics : Topic?
let permissions : Permissions?
let watchers : Double?
let default_branch : String?
// let score : Double?
// let subscribers_count : Double?
// let network_count : Double?
// let allow_rebase_merge: Bool?
// let allow_squash_merge: Bool?
// let allow_merge_commit: Bool?
}
struct Topic:Decodable {
let topics : [String]?
}
struct Permissions:Decodable {
let admin : Bool
let push : Bool
let pull : Bool
}
struct RepoList:Decodable{
let total_count : Int?
let incomplete_results : Bool?
let items : [Repo]?
}
struct User:Decodable {
let login: String?
let id: Double?
let avatar_url: String?
let gravatar_id: String?
let url: String?
let html_url: String?
let followers_url: String?
let following_url: String?
let gists_url: String?
let starred_url: String?
let subscriptions_url: String?
let organizations_url: String?
let repos_url: String?
let events_url: String?
let received_events_url: String?
let type: String?
let site_admin: Bool?
}
struct Creator:Decodable {
let login: String?
let id: Double?
let avatar_url: String?
let gravatar_id: String?
let url: String?
let html_url: String?
let followers_url: String?
let following_url: String?
let gists_url: String?
let starred_url: String?
let subscriptions_url: String?
let organizations_url: String?
let repos_url: String?
let events_url: String?
let received_events_url: String?
let type: String?
let site_admin: Bool?
}
struct Link:Decodable {
let href :String?
}
struct _Links:Decodable {
let `self` :Link?
let html :Link?
let issue :Link?
let comments :Link?
let review_comments :Link?
let review_comment :Link?
let commits :Link?
let statuses :Link?
}
struct Base:Decodable {
let label :String?
let ref :String?
let sha :String?
let user :User?
let repo :Repo?
}
struct Head:Decodable {
let label :String?
let ref :String?
let sha :String?
let user :User?
let repo :Repo?
}
struct Milestone:Decodable {
let url:String?
let html_url:String?
let labels_url:String?
let id: Double?
let number:Double?
let title:String?
let description:String?
let creator:Creator?
let open_issues:Double?
let closed_issues:Double?
let state:String?
let created_at:String?
let updated_at:String?
let closed_at:String?
let due_on:String?
}
struct Assignee:Decodable {
let login :String?
let id :Double?
let avatar_url :String?
let gravatar_id :String?
let url :String?
let html_url :String?
let followers_url :String?
let following_url :String?
let gists_url :String?
let starred_url :String?
let subscriptions_url :String?
let organizations_url :String?
let repos_url :String?
let events_url :String?
let received_events_url :String?
let type :String?
let site_admin :Bool?
}
struct Reviewers:Decodable {
let login: String?
let id: Double?
let avatar_url: String?
let gravatar_id: String?
let url: String?
let html_url: String?
let followers_url: String?
let following_url: String?
let gists_url: String?
let starred_url: String?
let subscriptions_url: String?
let organizations_url: String?
let repos_url: String?
let events_url: String?
let received_events_url: String?
let type: String?
let site_admin: Bool?
}
struct Pull:Decodable {
let id: Double?
let url:String?
let html_url:String?
let diff_url:String?
let patch_url:String?
let issue_url:String?
let number:Double?
let state:String?
let locked:Bool?
let title:String?
let user:User?
let body:String?
let created_at:String?
let updated_at:String?
let closed_at:String?
let merged_at:String?
let merge_commit_sha: String?
let assignee: Assignee?
let assignees: [Assignee]?
let requested_reviewers: [Reviewers]?
let milestone:Milestone?
let commits_url:String?
let review_comments_url:String?
let review_comment_url:String?
let comments_url:String?
let statuses_url:String?
let head:Head?
let base:Base?
let _links:_Links?
let author_association:String?
}
struct PullList:Decodable {
let pulls:[Pull]?
}
/////////////////////////////////////////////////////////
1.This one is working fine with this structs: 2.This one is the one that gives the typeMismatch error
Solution 1:
You're probably doing this right now:
let decoder = JSONDecoder()
let repoList = decoder.decode(RepoList.self, from: data)
which is fine for the response with a top-level Object.
To decode JSON responses that are top-level Arrays, use code like this instead:
let decoder = JSONDecoder()
let repos = decoder.decode([Repo].self, from: data)
Solution 2:
If you have a problematic JSON, which can contain number or string for some keys, you can decode object without that property and manually set that property after decoding.
For example, I have a Vehicle class inside HistoryItem. In Vehicle model_year can be empty String or non empty Int. Here I am decoding modelYear manually using NSDictionary and trying to get Int. Swift 4 cannot do it automatically.
do {
// Decoding HistoryItem from JSON
let jsonData = try JSONSerialization.data(withJSONObject: dict, options: .prettyPrinted)
let decoder = JSONDecoder()
let historyItem = try decoder.decode(HistoryItem.self, from: jsonData)
if let modelYear = (dict as NSDictionary).value(forKeyPath: "vehicle.model_year") as? Int {
historyItem.vehicle?.modelYear = modelYear
}
// Saving HistoryItem to Realm
let realm = try! Realm()
try! realm.write {
realm.add(historyItem, update: true)
}
} catch {
print(error.localizedDescription)
}
This is my Vehicle class that is contained inside HistoryItem:
class Vehicle: Object, Codable {
@objc dynamic var VIN: String = ""
@objc dynamic var make: String?
@objc dynamic var modelName: String?
@objc dynamic var recallCount: Int = 0
@objc dynamic var modelYear: Int = 0
override static func primaryKey() -> String? {
return "VIN"
}
private enum CodingKeys: String, CodingKey {
case VIN = "vin"
case make
case modelName = "model_name"
case recallCount = "recall_count"
}
}
As you see, there is no model_year key in CodingKeys.