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https://github.com/yonaskolb/Codability
Useful helpers for working with Codable types in Swift
https://github.com/yonaskolb/Codability
codable decoding encoding helpers json
Last synced: 3 months ago
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Useful helpers for working with Codable types in Swift
- Host: GitHub
- URL: https://github.com/yonaskolb/Codability
- Owner: yonaskolb
- License: mit
- Created: 2018-04-25T13:34:55.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2020-06-30T14:56:07.000Z (over 4 years ago)
- Last Synced: 2024-07-23T11:13:28.937Z (3 months ago)
- Topics: codable, decoding, encoding, helpers, json
- Language: Swift
- Homepage:
- Size: 25.4 KB
- Stars: 129
- Watchers: 7
- Forks: 7
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# Codability
[](https://swift.org/package-manager)
[](https://github.com/yonaskolb/Codability/releases)
[](https://circleci.com/gh/yonaskolb/Codability)
[](https://github.com/yonaskolb/Codability/blob/master/LICENSE)
Useful helpers for working with `Codable` types in Swift
- [Invalid Element Strategy](#invalid-element-strategy)
- [Any Codable](#any-codable)
- [Raw CodingKey](#raw-codingkey)
- [Generic Decoding Functions](#generic-decoding-functions)
## Installing
### Swift Package Manager
Add the following to your `Package.swift` dependencies:
```swift
.package(url: "https://github.com/yonaskolb/Codability.git", from: "0.2.0"),
```
And then import wherever needed: `import Codability`
## Helpers
### Invalid Element Strategy
By default Decodable will throw an error if a single element within an array or dictionary fails. `InvalidElementStrategy` is an enum that lets you control this behaviour. It has multiple cases:
- `remove`: Removes the element from the collection
- `fail`: Will fail the whole decoding. This is the default behaviour used by the decoders
- `fallback(value)`: This lets you provide a typed value in a type safe way
- `custom((EncodingError)-> InvalidElementStrategy)`: Lets you provide dynamic behaviour depending on the specific error that was throw which lets you lookup exactly which keys were involved
When decoding an array or dictionary use the `decodeArray` and `decodeDictionary` functions (there are also `IfPresent` variants as well).
The `InvalidElementStrategy` can either be passed into these functions, or a default can be set using `JSONDecoder().userInfo[.invalidElementStrategy]`, otherwise the default of `fail` will be used.
Given the following JSON:
```json
{
"array": [1, "two", 3],
"dictionary": {
"one": 1,
"two": "two",
"three": 3
}
}
```
```swift
struct Object: Decodable {
let array: [Int]
let dictionary: [String: Int]
public init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: RawCodingKey.self)
array = try container.decodeArray([Int].self, forKey: "array", invalidElementStrategy: .fallback(0))
dictionary = try container.decodeDictionary([String: Int].self, forKey: "dictionary", invalidElementStrategy: .remove)
}
}
```
```swift
let decoder = JSONDecoder()
// this will provide a default if none is passed into the decode functions
decoder.userInfo[.invalidElementStrategy] = InvalidElementStrategy.remove
let decodedObject = try decoder.decode(Object.self, from: json)
decodedObject.array == [1,0,3]
decodedObject.dictionary = ["one": 1, "three": 3]
```
### Any Codable
The downside of using Codable is that you can't encode and decode properties where the type is mixed or unknown, for example `[String: Any]`, `[Any]` or `Any`.
These are sometimes a neccessary evil in many apis, and `AnyCodable` makes supporting these types easy.
There are 2 few different way to use it:
#### As a Codable property
The advantage of this is you can use the synthesized codable functions.
The downside though is that these values must be unwrapped using `AnyCodable.value`. You can add custom setters and getters on your objects to make accessing these easier though
```swift
struct AnyContainer: Codable {
let dictionary: [String: AnyCodable]
let array: [AnyCodable]
let value: AnyCodable
}
```
#### Custom decoding and encoding functions
This lets you keep your normal structures, but requires using the `decodeAny` or `encodeAny` functions. If you have to implement a custom `init(from:)` or `encode` function for other reasons, this is the way to go. Behind the scenes this uses `AnyCodable` to do the coding, and then does a cast to your expect type in the case of decoding.
```swift
struct AnyContainer: Codable {
let dictionary: [String: Any]
let array: [Any]
let value: Any
public init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
dictionary = try container.decodeAny(.dictionary)
array = try container.decodeAny([Any].self, forKey: .array)
value = try container.decodeAny(Any.self, forKey: .value)
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encodeAny(dictionary, forKey: .dictionary)
try container.encodeAny(array, forKey: .array)
try container.encodeAny(value, forKey: .value)
}
enum CodingKeys: CodingKey {
case dictionary
case value
case array
}
}
```
### Raw CodingKey
`RawCodingKey` can be used to provide dynamic coding keys. It also remove the need to create the standard `CodingKey` enum when you are only using those values in once place.
```swift
struct Object: Decodable {
let int: Int
let bool: Bool
public init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: RawCodingKey.self)
int = try container.decode(Int.self, forKey: "int")
bool = try container.decode(Bool.self, forKey: "bool")
}
}
```
### Generic Decoding functions
The default decoding functions on `KeyedDecodingContainer` and `UnkeyedDecodingContainer` all require an explicity type to be passed in. `Codabilty` adds generic functions to remove the need for this, making your `init(from:)` much cleaner. The `key` parameter also becomes unnamed.
All the helper functions provided by `Codabality` such as the `decodeAny`, `decodeArray` or `decodeDictionary` functions also have these generic variants including `IfPresent`.
```swift
struct Object: Decodable {
let int: Int?
let bool: Bool
public init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: RawCodingKey.self)
// old
int = try container.decodeIfPresent(Int.self, forKey: "int")
bool = try container.decode(Bool.self, forKey: "bool")
// new
int = try container.decodeIfPresent("int")
bool = try container.decode("bool")
}
}
```
## Other Codability helpers
[JohnSundell/Codextended](https://github.com/JohnSundell/Codextended)
## Attributions
Thanks to @mattt and [Flight-School/AnyCodable](https://github.com/Flight-School/AnyCodable) for the basis of `AnyCodable` support. [License](https://github.com/Flight-School/AnyCodable/blob/master/LICENSE.md)