FestivalServer/Sources/App/routes.swift

import Vapor

private func register(_ req: Request, isAttending: Bool) -> String {
    guard let name = req.body.string?.trimmingCharacters(in: .whitespacesAndNewlines) else {
        return "No Name"
    }
    if isAttending {
        return add(guest: name)
    } else {
        return remove(guest: name)
    }
}

func routes(_ app: Application) throws {
    app.get { req in
        return "It works!"
    }

    app.get("festival", "api", "hello") { req in
        return "It works!"
    }

    app.get("hello") { req in
        return "It works!"
    }

    app.post("festival", "api", "register") { req -> String in
        register(req, isAttending: true)
    }
    
    app.post("festival", "api", "decline") { req -> String in
        register(req, isAttending: false)
    }
}