Decode Array<Any> and Dictionary<String, Any> Swift

import Foundation

// Inspired by https://gist.github.com/mbuchetics/c9bc6c22033014aa0c550d3b4324411a

struct JSONCodingKeys: CodingKey {
    var stringValue: String

    init?(stringValue: String) {
        self.stringValue = stringValue
    }

    var intValue: Int?

    init?(intValue: Int) {
        self.init(stringValue: "\(intValue)")
        self.intValue = intValue
    }
}


extension KeyedDecodingContainer {

    func decode(_ type: Dictionary<String, Any>.Type, forKey key: K) throws -> Dictionary<String, Any> {
        let container = try self.nestedContainer(keyedBy: JSONCodingKeys.self, forKey: key)
        return try container.decode(type)
    }

    func decodeIfPresent(_ type: Dictionary<String, Any>.Type, forKey key: K) throws -> Dictionary<String, Any>? {
        guard contains(key) else {
            return nil
        }
        return try decode(type, forKey: key)
    }

    func decode(_ type: Array<Any>.Type, forKey key: K) throws -> Array<Any> {
        var container = try self.nestedUnkeyedContainer(forKey: key)
        return try container.decode(type)
    }

    func decodeIfPresent(_ type: Array<Any>.Type, forKey key: K) throws -> Array<Any>? {
        guard contains(key) else {
            return nil
        }
        return try decode(type, forKey: key)
    }

    func decode(_ type: Dictionary<String, Any>.Type) throws -> Dictionary<String, Any> {
        var dictionary = Dictionary<String, Any>()

        for key in allKeys {
            if let if let boolValue = try? decode(Bool.self, forKey: key) {
                dictionary[key.stringValue] = boolValue
            } else if let stringValue = try? decode(String.self, forKey: key) {
                dictionary[key.stringValue] = stringValue
            } else intValue = try? decode(Int.self, forKey: key) {
                dictionary[key.stringValue] = intValue
            } else if let doubleValue = try? decode(Double.self, forKey: key) {
                dictionary[key.stringValue] = doubleValue
            } else if let fileMetaData = try? decode(Asset.FileMetadata.self, forKey: key) {
                dictionary[key.stringValue] = fileMetaData // Custom contentful type.
            } else if let nestedDictionary = try? decode(Dictionary<String, Any>.self, forKey: key) {
                dictionary[key.stringValue] = nestedDictionary
            } else if let nestedArray = try? decode(Array<Any>.self, forKey: key) {
                dictionary[key.stringValue] = nestedArray
            }
        }
        return dictionary
    }
}

extension UnkeyedDecodingContainer {

    mutating func decode(_ type: Array<Any>.Type) throws -> Array<Any> {
        var array: [Any] = []
        while isAtEnd == false {
            if let value = try? decode(Bool.self) {
                array.append(value)
            } else if let value = try? decode(Double.self) {
                array.append(value)
            } else if let value = try? decode(String.self) {
                array.append(value)
            } else if let nestedDictionary = try? decode(Dictionary<String, Any>.self) {
                array.append(nestedDictionary)
            } else if let nestedArray = try? decode(Array<Any>.self) {
                array.append(nestedArray)
            }
        }
        return array
    }

    mutating func decode(_ type: Dictionary<String, Any>.Type) throws -> Dictionary<String, Any> {

        let nestedContainer = try self.nestedContainer(keyedBy: JSONCodingKeys.self)
        return try nestedContainer.decode(type)
    }
}

change decoder to check for bool at first. because true will be decoded to int 1, so check for bool will drop

@hashemp206 done, good catch ;-)

@loudmouth, did you have a license in mind for this gist? Looks just like the kind of thing I've been looking for, to work with my Codable stuff for JSON parsing...

Good work!

I've added encoder
https://github.com/3D4Medical/gltf_scenekit/blob/master/Sources/gltf_scenekit/GLTF/JSONCodingKeys.swift

Correcting the above link from @sakrist: https://github.com/3D4Medical/glTFSceneKit/blob/master/Sources/glTFSceneKit/GLTF/JSONCodingKeys.swift

@loudmouth
Few mistakes:

• if let if let boolValue -> if let boolValue
• } else intValue -> } else if let intValue

One more check to see if the value of the key is null then return nil

func decodeIfPresent(_ type: Dictionary<String, Any>.Type, forKey key: K) throws -> Dictionary<String, Any>? {
        guard contains(key) else {
            return nil
        }
        guard try decodeNil(forKey: key) else {
            return nil
        }
        return try decode(type, forKey: key)
    }

dude! you save my time

Thanks for this code!

One of our API's returned an array where one of the values was 'null', which got the [Any] decoder into an infinite loop.
Fixed it this way:

mutating func decode(_ type: Array<Any>.Type) throws -> Array<Any> {
        var array: [Any] = []

        while isAtEnd == false {
            // When one of the values is `null`, we seem to enter an infinite loop.. Check if the value is null and continue if so
            do {
                let value: String? = try decode(String?.self)
                if value == nil {
                    // Found a nil value... skip the rest of this function and continue with the next value
                    continue
                }
            } catch {
                // if we fail, it isn't a String? and isn't nil
                // continue with testing values
            }

            if let value = try? decode(Bool.self) {
                array.append(value)

            } else if let value = try? decode(Int.self) {
                array.append(value)

            } else if let value = try? decode(Double.self) {
                array.append(value)

            } else if let value = try? decode(String.self) {
                array.append(value)

            } else if let nestedDictionary = try? decode(JSON.self) {
                array.append(nestedDictionary)

            } else if let nestedArray = try? decode(Array<Any>.self) {
                array.append(nestedArray)
            }
        }
        return array
    }

@ChiellieNL thanks for sharing that fix! I had to replace the line with JSON.self to the original line to get it to compile on my end.

Here is my version with decoding (original post), encoding (thank you @sakrist!) and the null fix from above. I also changed the types to the modern syntax of [Any] instead of Array<Any>, and [String: Any] instead of Dictionary<String, Any>.

https://gist.github.com/mikebuss/17142624da4baf9cdcc337861e256533

@converted2mac I guess Github doesn't give notifications for comments on Gists 🤔

Anyway, no license, i'd say go ahead and use the code as you need ;-)

@mikebuss null value should be appended to the array as well. There were a couple of bugs including 2 infinite loops for encoding/decoding [Any]. I've created a new version that works well with all cases and fixed all the bugs that I found.
https://gist.github.com/sukov/d3834c0e7b72e4f7575f753b352f6ddd

Thanks for sharing this! I really need it :)

Thanks for this. I think if you renamed the gist to end in .swift instead of [space]Swift syntax highlighting will be added.

Thanks for sharing this 👍