JSONStringConvertible.swift

import Foundation

public protocol JSONStringConvertible: class {
    var jsonString: String { get }
}

extension Logger {
    // Converts an arbitrary object into some that is JSON-safe
    static func makeJSONObject(_ object: Any) -> Any {
        if let jsonObj = object as? JSONStringConvertible {
            return jsonObj.jsonString
        }

        // Fragments are legal, so start by putting it in an array
        if JSONSerialization.isValidJSONObject([object]) {
            return object
        }

        switch object {

        case let dict as [String: Any]:
            var jsonDict: [String: Any] = [:]
            for (key, value) in dict {
                jsonDict[key] = makeJSONObject(value)
            }
            return jsonDict

        case let dict as NSDictionary:
            var jsonDict: [String: Any] = [:]
            for (key, value) in dict {
                jsonDict["\(key)"] = makeJSONObject(value)
            }
            return jsonDict

        case let array as [Any]:
            return array.map(makeJSONObject)

        default:
            return "\(object)"
        }
    }

    // Converts an arbitrary (NSDictionary-safe) dictionary into a JSON string.
    static func makeJSONString(_ dictionary: [String: Any]) -> String {
        do {
            return String(
                data: try JSONSerialization.data(withJSONObject: makeJSONObject(dictionary), options: []),
                encoding: String.Encoding.utf8)!
                .replacingOccurrences(of: "\\/", with: "/") // NSJSONSerialization quotes forward slashes when it doesn't need to
        } catch {
            Swift.assertionFailure("Could not convert JSON: \(error)") // Do not use Log.* methods. We're inside of Log.
            return ""
        }
    }
}