Arrow
Reason - Example - Installation
identifier <-- json["id"]
name <-- json["name"]
stats <-- json["stats"]Because parsing JSON in Swift is full of unecessary if lets, obvious casts and nil-checks
There must be a better way
Try it
Arrow is part of freshOS iOS toolset. Try it in an example App ! Download Starter Project
How
By using a simple arrow operator that takes care of the boilerplate code for us.
Json mapping code becomes concise and maintainable
Why use Arrow
- Infers types
- Leaves your models clean
- Handles custom & nested models
- Dot and array syntax
- Pure Swift, Simple & Lightweight
Example
Swift Model
struct Profile {
var identifier = 0
var name = ""
var link:NSURL?
var weekday:WeekDay = .Monday
var stats = Stats()
var phoneNumbers = [PhoneNumber]()
}JSON File
{
"id": 15678,
"name": "John Doe",
"link": "https://apple.com/steve",
"weekdayInt" : 3,
"stats": {
"numberOfFriends": 163,
"numberOfFans": 10987
},
"phoneNumbers": [{
"label": "house",
"number": "9809876545"
}, {
"label": "cell",
"number": "0908070656"
}, {
"label": "work",
"number": "0916570656"
}]
}Before (Chaos)
var profile = Profile()
// Int
if let id = json["id"] as? Int {
profile.identifier = id
}
// String
if let name = json["name"] as? String {
profile.name = name
}
// NSURL
if let link = json["link"] as? String, url = NSURL(string:link) {
profile.link = link
}
// Enum
if let weekdayInt = json["weekdayInt"] as? Int, weekday = WeekDay(rawValue:weekdayInt) {
profile.weekday = weekday
}
// Custom nested object
if let statsJson = json["stats"] as? AnyObject {
if let numberOfFans = statsJson["numberOfFans"] as? Int {
profile.stats.numberOfFans = numberOfFans
}
if let numberOfFriends = statsJson["numberOfFriends"] as? Int {
profile.stats.numberOfFriends = numberOfFriends
}
}
// Array of custom nested object
if let pns = json["phoneNumbers"] as? [AnyObject] {
for pn in pns {
phoneNumbers.append(PhoneNumber(json: pn))
}
}After 🎉 🎉 🎉
extension Profile:ArrowParsable {
mutating func deserialize(json: JSON) {
identifier <-- json["id"]
link <-- json["link"]
name <-- json["name"]
weekday <-- json["weekdayInt"]
stats <- json["stats"]
phoneNumbers <-- json["phoneNumbers"]
}
}Usage
let profile = Profile()
profile.deserialize(json)Installation
Carthage
github "freshOS/Arrow"
CocoaPods
target 'MyApp'
pod 'Arrow'
use_frameworks!
Manually
Simply Copy and Paste .swift files in your Xcode Project :)
As A Framework
Grab this repository and build the Framework target on the example project. Then Link against this framework.
How Does That Work
Notice earlier we typed :
stats <-- json["stats"]That's because we created and extension "Stats+Arrow.swift" enabling us to use the Arrow Operator
// Stats+Arrow.swift
import Foundation
extension Stats:ArrowParsable {
mutating func deserialize(json: JSON) {
numberOfFriends <-- json["numberOfFriends"]
numberOfFans <-- json["numberOfFans"]
}
}Flexible you said
- DO I have to use the <-- for my sub models
- Nope, you could write it like so if you wanted :
stats.numberOfFriends <-- json["stats.numberOfFriends"]
stats.numberOfFans <-- json["stats.numberOfFans"]Date Parsing
Globally
// Configure Global Date Parsing with one of those
Arrow.setDateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZZ")
Arrow.setUseTimeIntervalSinceReferenceDate(true)
Arrow.setDateFormatter(aDateFormatter)
// Then later dates can be parsed form custom date format or timestamps automatically 🎉
let json:JSON = JSON(["date": "2013-06-07T16:38:40+02:00", "timestamp": 392308720])
date1 <-- json["date"]
date2 <-- json["timestamp"]On a per-key basis
createdAt <-- json["created_at"]?.dateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZZ")
createdAt <-- json["created_at"]?.dateFormatter(aCustomDateFormatter)Just provide it on a case per case basis !
Accessing JSON values
Nested values
value <-- json["nested.nested.nested.nestedValue"]Object at index
value <-- json[12]Combine both
value <-- json[1]?["someKey"]?[2]?["something.other"]Looping on Array
if let collection = json.collection {
for jsonEntry in collection {
//Do something
}
}Swift Version
- Swift 2 -> version 2.0.3
- Swift 3 -> version 3.0.5
- Swift 4 -> version 4.0.0
- Swift 4.1 -> version 4.1.0
- Swift 4.2 -> version 4.2.0
- Swift 5.0 -> version 5.0.0
- Swift 5.1 -> version 5.1.0
- Swift 5.1.3 -> version 5.1.1
Acknoledgments
This wouldn't exist without YannickDot, Damien-nd and maxkonovalov
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