Using IkigaJSON instead of Foundation in Vapor 3

1_IkigaJSON+Vapor.swift

import Vapor
import IkigaJSON

extension IkigaJSONDecoder: DataDecoder {
    public func decode<D>(_ decodable: D.Type, from data: LosslessDataConvertible) throws -> D where D : Decodable {
        return try self.decode(decodable, from: data.convertToData())
    }
}

extension IkigaJSONEncoder: DataEncoder {
}

extension IkigaJSONDecoder: HTTPMessageDecoder {
    /// See `HTTPMessageDecoder`
    public func decode<D, M>(_ decodable: D.Type, from message: M, maxSize: Int, on worker: Worker) throws -> EventLoopFuture<D>
        where D: Decodable, M: HTTPMessage
    {
        guard message.contentType == .json else {
            throw HTTPError(identifier: "contentType", reason: "HTTP message did not have JSON-compatible content-type.")
        }
        return message.body.consumeData(max: maxSize, on: worker).map(to: D.self) { data in
            return try self.decode(D.self, from: data)
        }
    }
}

extension IkigaJSONEncoder: HTTPMessageEncoder {
    /// See `HTTPMessageEncoder`
    public func encode<E, M>(_ encodable: E, to message: inout M, on worker: Worker) throws
        where E: Encodable, M: HTTPMessage
    {
        message.contentType = .json
        message.body = try HTTPBody(data: encode(encodable))
    }
}

2_configure.swift

import Vapor
import IkigaJSON

public func configure(_ config: inout Config, _ env: inout Environment, _ services: inout Services) throws {
    // ... other configuration omitted for brevity ...

    let content: ContentConfig = {
        var content = ContentConfig.default()
        var decoderSettings = JSONDecoderSettings()
        var encoderSettings = JSONEncoderSettings()

        decoderSettings.dataDecodingStrategy = .base64
        encoderSettings.dataEncodingStrategy = .base64
        encoderSettings.encodeNilAsNull = true

        if #available(OSX 10.12, *) {
            decoderSettings.dateDecodingStrategy = .iso8601
            encoderSettings.dateEncodingStrategy = .iso8601
        } else {
            // never actually hit on Linux or modern macOS
        }

        let decoder = IkigaJSONDecoder(settings: decoderSettings)
        var encoder = IkigaJSONEncoder()
        encoder.settings = encoderSettings

        content.use(httpDecoder: decoder, for: .json)
        content.use(httpEncoder: encoder, for: .json)
        return content
    }()


    services.register(content)
    
    // ...
}

3_Package.swift

// swift-tools-version:4.0
import PackageDescription

let package = Package(
    name: "VaporApp",
    dependencies: [
        // ...other dependencies omitted...
        .package(url: "https://github.com/Ikiga/IkigaJSON.git", from: "1.1.0"),
    ],
    targets: [
        .target(name: "App", dependencies: [...other dependencies..., "IkigaJSON"]),
        .target(name: "Run", dependencies: ["App"]),
    ]
)