JSON Parsing With Codable

Installation

pod 'AlamofireCodable'

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

Xcode 9+ , Swift 4+

Usage

Given a URL which returns weather data in the following form:

{  
   "data":{  
      "location":"Toronto, Canada",
      "three_day_forecast":[  
         {  
            "conditions":"Partly cloudy",
            "day":"Monday",
            "temperature":20
         },
         {  
            "conditions":"Showers",
            "day":"Tuesday",
            "temperature":22
         },
         {  
            "conditions":"Sunny",
            "day":"Wednesday",
            "temperature":28
         }
      ]
   }
}

You can use the extension as the follows:

import AlamofireCodable

        let form = WeatherForm()
        Alamofire.request(
                form.url,
                method: HTTPMethod.get,
                parameters: form.parameters(),
                encoding: form.encoding(),
                headers: form.headers()
            )
            .responseObject(keyPath: "data",completionHandler: { (response: DataResponse<Weather>) in
                switch response.result {
                case .success(let object):
                    debugPrint("🌹", object.location)
                case .failure(let error):
                    debugPrint("🌹", error.localizedDescription)
                }
            })

The Weather object in the completion handler is a custom object which you define. The only requirement is that the object must conform to Codable protocol. In the above example, the Weather object looks like the following:

{  
   "data":{  
      "location":"Toronto, Canada",
      "three_day_forecast":[  
         {  
            "conditions":"Partly cloudy",
            "day":"Monday",
            "temperature":20
         },
         {  
            "conditions":"Showers",
            "day":"Tuesday",
            "temperature":22
         },
         {  
            "conditions":"Sunny",
            "day":"Wednesday",
            "temperature":28
         }
      ]
   }
}

The extension uses Generics to allow you to create your own custom response objects. Below is the responseObject function definition. Just replace T in the completionHandler with your custom response object and the extension handles the rest:

public func responseObject<T: Codable>(queue: DispatchQueue? = nil, keyPath: String? = nil,  completionHandler: @escaping (DataResponse<T>) -> Void) -> Self 

The responseObject function has 2 optional parameters and a required completionHandler:

• queue: The queue on which the completion handler is dispatched.
• keyPath: The key path of the JSON where object mapping should be performed
• completionHandler: A closure to be executed once the request has finished and the data has been decoded by JSONDecoder.

Easy decode of Nested Objects

AlamofireCodable supports dot notation within keys for easy mapping of nested objects. Given the following JSON String:

{  
   "data":{  
      "location":"Toronto, Canada",
      "three_day_forecast":[  
         {  
            "conditions":"Partly cloudy",
            "day":"Monday",
            "temperature":20
         },
         {  
            "conditions":"Showers",
            "day":"Tuesday",
            "temperature":22
         },
         {  
            "conditions":"Sunny",
            "day":"Wednesday",
            "temperature":28
         }
      ]
   }
}

You can access the nested objects as follows:

      let form = WeatherForm()
        Alamofire.request(
            form.url,
            method: HTTPMethod.get,
            parameters: form.parameters(),
            encoding: form.encoding(),
            headers: form.headers()
            )
            .responseObject(completionHandler: { (response: DataResponse<RootModel>) in
                switch response.result {
                case .success(let root):
                    debugPrint("🌹", root)
                case .failure(let error):
                    debugPrint("🌹", error.localizedDescription)
                }
            })

KeyPath

The keyPath variable is used to drill down into a JSON response and only map the data found at that keyPath. It supports nested values such as data.three_day_forecast to drill down several levels in a JSON response.

let form = WeatherForm()
        Alamofire.request(
                form.url,
                method: HTTPMethod.get,
                parameters: form.parameters(),
                encoding: form.encoding(),
                headers: form.headers()
            )
            .responseArray(keyPath: "data.three_day_forecast", completionHandler: { (response: DataResponse<[Forecast]>) in
                switch response.result {
                case .success(let array):
                    debugPrint("🌹", array)
                case .failure(let error):
                    debugPrint("🌹", error.localizedDescription)
                }
            })

Array Responses

If you have an endpoint that returns data in Array form you can map it with the following function:

public func responseArray<T: Codable>(queue: DispatchQueue? = nil, keyPath: String? = nil, completionHandler: @escaping (DataResponse<[T]>) -> Void) -> Self 

For example, if your endpoint returns the following:

[
    { 
        "conditions": "Partly cloudy",
        "day" : "Monday",
        "temperature": 20 
    },
    { 
        "conditions": "Showers",
        "day" : "Tuesday",
        "temperature": 22 
    },
    { 
        "conditions": "Sunny",
        "day" : "Wednesday",
        "temperature": 28 
    }
]

You can request and map it as follows:

        let form = WeatherForm()
        Alamofire.request(
                form.url,
                method: HTTPMethod.get,
                parameters: form.parameters(),
                encoding: form.encoding(),
                headers: form.headers()
            )
            .responseArray(keyPath: "data.three_day_forecast", completionHandler: { (response: DataResponse<[Forecast]>) in
                switch response.result {
                case .success(let array):
                    debugPrint("🌹", array)
                case .failure(let error):
                    debugPrint("🌹", error.localizedDescription)
                }
            })

Author

License

AlamofireCodable is available under the MIT license. See the LICENSE file for more info.