Parse JSON like a badass

Full disclaimer regarding performance

For production apps (or if you care about efficiency at all), I highly recommend using SwiftyJSON over this library. After benchmarking, I found that SwiftJSONParser could be up to 7x slower than SwiftyJSON.

This sucks

let jsonData = NSData(contentsOfURL: NSURL(string: url))
var jsonErrorOptional: NSError?
let jsonOptional: AnyObject! = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions(0), error: &jsonErrorOptional)

if let json = jsonOptional as? Dictionary<String, AnyObject> {
    if let other = json["other"] as? Dictionary<String, AnyObject> {
        if let nicknames = other["nicknames"] as? Array<String> {
            if let handle = nicknames[0] as AnyObject? as? String {
                println("Some folks call me \(handle)")
            }
        }
    }
}

This is readable

let jsonData = NSData(contentsOfURL: NSURL(string: url))
let parser = JSONParser(jsonData)

if let handle = parser.getString("other.nicknames[0]") {
    println("Some folks call me \(handle)")
}

Usage

Sample JSON payload we want to parse

{
    "name": "Mike",
    "favorite_number": 19,
    "gpa": 2.6,
    "favorite_things": ["Github", 42, 98.6],
    "other": {
        "city": "San Francisco",
        "commit_count": 9000,
        "nicknames": ["mrap", "Mikee"]
    }
}

Get values of a specific type. Returns optionals

if let name = parser.getString("name") {
    println("My name is \(name)")
}

if let number = parser.getInt("favorite_number") {
    println("\(number) is my favorite number!")
}

if let gpa = parser.getDouble("gpa") {
    println("My stellar highschool gpa was \(gpa)")
}

Or get AnyObject if you're not sure

if let city = parser.get("other.city") {
    // city will be type AnyObject
}

Get an Array of values

if let favorites = parser.getArray("favorite_things") {
    // favorites => ["Github", 42, 98.6]
}

Error Handling

If you're not sure about incoming json data, check it first

let badJsonData = NSData(contentsOfURL: NSURL(string: url))
let parser = JSONParser(badJsonData)

// Check for an error
if parser.error != nil {
   // Do stuff with json
} else {
   // Handle the error
   println(parser.error)
}

Installation

The best way to use SwiftJSONParser is to import it as a framework.

1. Clone a local copy of SwiftJSONParser in any directory you'd like. git clone git@github.com:mrap/SwiftJSONParser.git

2. Drag SwiftJSONParser.xcodeproj into your project's project navigator

3. Add SwiftJSONParser as a Target Dependency.

• Go to your App Target > Build Phases
• In Target Dependencies, press +, select SwiftJSONParser