how to parse a uuid from a bearer token header

[jaredh159]

thanks for the great library, i'm a pointfree subscriber and a big fan of your work 👍

i'm trying to figure out if i can model the concept of whole subsets of routes that are authenticated by various methods, where the nested route enums would get access to previously parsed off data. for instance, imagine routes like this:

enum AppRoute {
  case home
  case headerAuthed(UUID, AuthedRoute)
  //                ^--- uuid from Bearer token header
}

enum AuthedRoute {
  case foo
  case bar
}

i'm trying model the idea that for certain routes, i should always be able to pull a UUID out of the Authorization: Bearer <token> header. I feel like this should be possible, but i'm stuck trying to implement the router/parser. Here's sort of what I've got, in a nutshell:

let authedRouter = OneOf {
  Route(.case(AuthedRoute.foo)) {
    Path { "foo" }
  }
  Route(.case(AuthedRoute.bar)) {
    Path { "bar" }
  }
}

let appRouter = OneOf {
  Route(.case(AppRoute.home))
  Route(.case(AppRoute.headerAuthed)) {
    Headers {
      Field("Authorization") {
        Skip { "Bearer " }
        UUID.parser()
      }
    }
    // ^^^--- this is where i'm totally lost...
    authedRouter
  }
}

[mackoj]

Hi @jaredh159,

I don't really understand your issue here. When I try your code it works as expected.

Example Code

// This Playground was generated by the SPI-Playgrounds app, which is part of the
// Swift Package Index (https://swiftpackageindex.com), using 🏟 Arena
// (https://github.com/finestructure/arena) to import the dependency.
//
// For more information about the SPI-Playgrounds app and to download it, visit
// https://swiftpackageindex.com/try-in-a-playground

import URLRouting
import Foundation

enum AppRoute {
  case home
  case headerAuthed(UUID, AuthedRoute)
}

enum AuthedRoute {
  case foo
  case bar
}

let authedRouter = OneOf {
  Route(.case(AuthedRoute.foo)) {
    Path { "foo" }
  }
  Route(.case(AuthedRoute.bar)) {
    Path { "bar" }
  }
}

let appRouter = OneOf {
  Route(.case(AppRoute.home))
  Route(.case(AppRoute.headerAuthed)) {
    Headers {
      Field("Authorization") {
        Skip { "Bearer " }
        UUID.parser()
      }
    }
    authedRouter
  }
}

var request = URLRequest(url: URL(string: "/bar")!)
request.allHTTPHeaderFields = ["Authorization" : "Bearer 9cd91192-0217-415f-bb1a-230399e0b7a4" ]
var requestData = URLRequestData(request: request)!
print(try appRouter.parse(requestData))
// headerAuthed(9CD91192-0217-415F-BB1A-230399E0B7A4, __lldb_expr_35.AuthedRoute.bar)

request = URLRequest(url: URL(string: "/")!)
requestData = URLRequestData(request: request)!
print(try appRouter.parse(requestData))
// home

[jaredh159]

thanks for the reply. I wonder if maybe I was having some other problem that was unrelated that made me not realize that the code I showed was more or less correct.

in the meantime, since i control the client and the server, i just switched to a header scheme that doesn't involve the Bearer prefix, but i may revisit this, now that you've showed I was basically on the right track.