Vapor버전 4.0을 기준으로 작성된 게시글입니다! struct Hello: Content { var name: String? } extension Hello: Validatable { static func validations(_ validations: inout Validations) { validations.add("name", as: String.self, is: .count(3...)) } } app.get("validation") { req -> String in try Hello.validate(query: req) let name = try req.query.decode(Hello.self).name! req.logger.info("validation test") return name..