Parameters

Parameters are a registered type that can be initialized from a String.

They can be part of a Route, and be extracted from requests that are called in that route.

Creating custom parameters

To create a custom parameter type, simply conform to Parameter and implement the conversion function make and a unique slug.

In this example, the User class will be initialized from a parameter that represents its identifier.

We recommend prefixing custom Parameter identifiers.

  1. class User : Parameter {
  2.   var username: String
  4.   // The unique (prefixed) identifier for this type
  5.   static var uniqueSlug = "my-app:user"
  7.   // Creates a new user from the raw `parameter`
  8.   static func make(for parameter: String, in request: Request) throws -> User {
  9.     return User(named: parameter)
  10.   }
  12.   init(named username: String) {
  13.     self.username = username
  14.   }
  15. }

Using (custom) parameters

After conforming a type to Parameter you can access its static property parameter as part of a path.

  1. router.on(.get, to: "users", User.parameter, "profile") { request in
  2.   let user = try request.parameter(User.self)
  4.   // Return the user's Profile sync or async (depending on the router)
  5. }