Alamofire-SwiftyJSON.swift

//
//  AlamofireSwiftyJSON.swift
//  AlamofireSwiftyJSON
//
//  Created by Pinglin Tang on 14-9-22.
//  Copyright (c) 2014 SwiftyJSON. All rights reserved.
//

import Foundation
import Alamofire
import SwiftyJSON

private let emptyDataStatusCodes: Set<Int> = [204, 205]

extension Request {
    /// Returns a SwiftyJSON object contained in a result type constructed from the response data using `JSONSerialization`
    /// with the specified reading options.
    ///
    /// - parameter options:  The JSON serialization reading options. Defaults to `.allowFragments`.
    /// - parameter response: The response from the server.
    /// - parameter data:     The data returned from the server.
    /// - parameter error:    The error already encountered if it exists.
    ///
    /// - returns: The result data type.
    public static func serializeResponseSwiftyJSON(
        options: JSONSerialization.ReadingOptions,
        response: HTTPURLResponse?,
        data: Data?,
        error: Error?
    ) -> Result<JSON> {
        if let error = error {
            return .failure(error)
        }

        if let response = response, emptyDataStatusCodes.contains(response.statusCode) {
            return .success(JSON.null)
        }

        guard let validData = data, validData.count > 0 else {
            return .failure(AFError.responseSerializationFailed(reason: .inputDataNilOrZeroLength))
        }

        do {
            let json = try JSONSerialization.jsonObject(with: validData, options: options)
            return .success(JSON(json))
        } catch {
            return .failure(AFError.responseSerializationFailed(reason: .jsonSerializationFailed(error: error)))
        }
    }
}

extension DataRequest {
    /// Creates a response serializer that returns a SwiftyJSON object result type constructed from the response data using
    /// `JSONSerialization` with the specified reading options.
    ///
    /// - parameter options: The JSON serialization reading options. Defaults to `.allowFragments`.
    ///
    /// - returns: A JSON object response serializer.
    public static func swiftyJSONResponseSerializer(
        options: JSONSerialization.ReadingOptions = .allowFragments
    ) -> DataResponseSerializer<JSON> {
        return DataResponseSerializer { _, response, data, error in
            return Request.serializeResponseSwiftyJSON(options: options, response: response, data: data, error: error)
        }
    }

    /// Adds a handler to be called once the request has finished.
    ///
    /// - parameter options: The JSON serialization reading options. Defaults to `.allowFragments`.
    /// - parameter completionHandler: A closure to be executed once the request has finished.
    ///
    /// - returns: The request.
    @discardableResult
    public func responseSwiftyJSON(
        queue: DispatchQueue? = nil,
        options: JSONSerialization.ReadingOptions = .allowFragments,
        completionHandler: @escaping (DataResponse<JSON>) -> Void
    ) -> Self {
        return self.response(
            queue: queue,
            responseSerializer: DataRequest.swiftyJSONResponseSerializer(options: options),
            completionHandler: completionHandler
        )
    }
}