ObjectMapper

Forked.

ObjectMapper is a framework written in Swift that makes it easy for you to convert your Model objects to and from JSON. ##Features:

• Mapping JSON to objects
• Mapping objects to JSON
• Nested Objects (stand alone, in Arrays or in Dictionaries)
• Custom transformations during mapping

##The Basics To support mapping, a class just needs to implement the MapperProtocol. ObjectMapper uses the "<=" operator to define how each member variable maps to and from JSON.

class User: MapperProtocol {

    var username: String?
    var age: Int?
    var weight: Double?
    var arr: [AnyObject]?
    var dict: [String : AnyObject] = [:]
    var friend: User?                       // Nested User object
    var birthday: NSDate?

    required init(){}

    // MapperProtocol    
    func map(mapper: Mapper) {
        username <= mapper["username"]
        age <= mapper["age"]
        weight <= mapper["weight"]
        arr <= mapper["arr"]
        dict <= mapper["dict"]
        friend <= mapper["friend"]
        birthday <= (mapper["birthday"], DateTransform<NSDate, Int>())
    }
}

Once your class implements MapperProtocol, the Mapper class handles everything else for you:

Convert a JSON string to a model object:

let user = Mapper().map(string: JSONString, toType: User.self)

Convert a model object to a JSON string:

let JSONString = Mapper().toJSONString(user)

Object mapper can map classes composed of the following types:

• Int
• Bool
• Double
• Float
• String
• Array<AnyObject>
• Dictionary<String, AnyObject>
• Optionals of all the abovee
• Object<T: MapperProtocol>
• Array<T: MapperProtocol>
• Dictionary<String, T: MapperProtocol>

##Custom Transfoms ObjectMapper also supports custom Transforms that convert values during the mapping process. To use a transform, simply create a tuple with the mapper["field_name"] and the transform of choice on the right side of the '<=' operator:

birthday <= (mapper["birthday"], DateTransform<NSDate, Int>())

The above transform will convert the JSON Int value to an NSDate when reading JSON and will convert the NSDate to an Int when converting objects to JSON.

You can easily create your own custom transforms by subclassing and overriding the methods in the MapperTransform class:

public class MapperTransform<ObjectType, JSONType> {
    init(){}
    
    func transformFromJSON(value: AnyObject?) -> ObjectType? {
        return nil
    }
    
    func transformToJSON(value: ObjectType?) -> JSONType? {
        return nil
    }
}

##Easy Mapping of Nested Objects ObjectMapper supports dot notation within keys for easy mapping of nested objects. Given the following JSON String:

"distance" : {
     "text" : "102 ft",
     "value" : 31
}

You can access the nested objects as follows:

func map(mapper: Mapper){
    distance <= mapper["distance.value"]
}

##To Do

• Support for implicitly unwrapped optionals (ex. var user: User!)
• Add support for custom Transforms that are defined outside the ObjectMapper project. Currently, if an operator is defined outside the project, there is an error on the custom operator (ex error: "Cannot invoke '<=' with an argument list of type '(@lvalue NSDate?, (@lvalue Mapper, DateTransform))’")

##Installation Due to the current lack of proper infrastructure for Swift dependency management, using ObjectMapper in your project requires the following steps:

1. Add ObjectMapper as a submodule by opening the Terminal, cd-ing into your top-level project directory, and entering the command git submodule add https://github.com/Hearst-DD/ObjectMapper.git
2. Open the ObjectMapper folder, and drag ObjectMapper.xcodeproj into the file navigator of your app project.
3. In Xcode, navigate to the target configuration window by clicking on the blue project icon, and selecting the application target under the "Targets" heading in the sidebar.
4. Ensure that the deployment target of ObjectMapper.framework matches that of the application target.
5. In the tab bar at the top of that window, open the "Build Phases" panel.
6. Expand the "Target Dependencies" group, and add ObjectMapper.framework.
7. Click on the + button at the top left of the panel and select "New Copy Files Phase". Rename this new phase to "Copy Frameworks", set the "Destination" to "Frameworks", and add ObjectMapper.framework.