19

API Authentication, Part 2 Written by Tim Condon

Now that you’ve implemented API authentication, neither your tests nor the iOS application work any longer. In this chapter, you’ll learn the techniques needed to account for the new authentication requirements.

Note: You must have PostgreSQL set up and configured in your project. If you still need to do this, follow the steps in Chapter 6, “Configuring a Database”.

Updating the tests

In the previous chapter, you updated the tests to ensure they compile. However, many of the tests won’t pass as you’ve protected all the routes in your API.

First, open Models+Testable.swift and, at the top of the file, add:

import Vapor

This allows the compiler to see the Bcrypt function used for password hashing. Next, replace create(name:username:on:) in the User extension with the following:

// 1
static func create(
  name: String = "Luke",
  username: String? = nil,
  on database: Database
) throws -> User {
  let createUsername: String
  // 2
  if let suppliedUsername = username {
    createUsername = suppliedUsername
  // 3
  } else {
    createUsername = UUID().uuidString
  }

  // 4
  let password = try Bcrypt.hash("password")
  let user = User(
    name: name,
    username: createUsername,
    password: password)
  try user.save(on: database).wait()
  return user
}

Here’s what you changed:

1. Make the username parameter an optional string that defaults to nil.
2. If a username is supplied, use it.
3. If a username isn’t supplied, create a new, random one using UUID. This ensures the username is unique as required by the migration.
4. Hash the password and create a user.

In Terminal, run the following:

# 1
docker rm  -f postgres-test
# 2
docker run --name postgres-test -e POSTGRES_DB=vapor-test \
  -e POSTGRES_USER=vapor_username \
  -e POSTGRES_PASSWORD=vapor_password \
  -p 5433:5432 -d postgres

Here’s what this does:

1. Stop and remove the test PostgreSQL container, if it exists, so you start with a fresh database.
2. Run the test container again as described in Chapter 11, “Testing”.

If you run the tests now, they crash since calls to any authenticated routes fail. You need to provide authentication for these requests.

Stop the tests, open Application+Testable.swift and replace:

import XCTVapor
import App

with the following:

@testable import App
@testable import XCTVapor

This enables you to use Token, User and XCTApplicationTester. Next, at the bottom of the file, insert:

// 1
extension XCTApplicationTester {
  // 2
  public func login(
    user: User
  ) throws -> Token {
    // 3
    var request = XCTHTTPRequest(
      method: .POST,
      url: .init(path: "/api/users/login"),
      headers: [:],
      body: ByteBufferAllocator().buffer(capacity: 0)
    )
    // 4
    request.headers.basicAuthorization = 
      .init(username: user.username, password: "password")
    // 5
    let response = try performTest(request: request)
    // 6
    return try response.content.decode(Token.self)
  }
}

Here’s what the new function does:

1. Add an extension to XCTApplicationTester, Vapor’s test wrapper around Application.
2. Define a log in method that takes User and returns Token.
3. Create a test POST request to /api/users/login — the log in URL — with empty values where needed.
4. Set the HTTP Basic Authentication header using Vapor’s BasicAuthorization helpers. Note: The password here must be plaintext text, not the hashed password from User.
5. Send the request to get the response.
6. Decode the response to Token and return the result.

Next, at the bottom of the XCTApplicationTester extension, add a new method to use the log in method you just created:

// 1
@discardableResult
public func test(
  _ method: HTTPMethod,
  _ path: String,
  headers: HTTPHeaders = [:],
  body: ByteBuffer? = nil,
  loggedInRequest: Bool = false,
  loggedInUser: User? = nil,
  file: StaticString = #file,
  line: UInt = #line,
  beforeRequest: (inout XCTHTTPRequest) throws -> () = { _ in },
  afterResponse: (XCTHTTPResponse) throws -> () = { _ in }
) throws -> XCTApplicationTester {
  // 2
  var request = XCTHTTPRequest(
    method: method,
    url: .init(path: path),
    headers: headers,
    body: body ?? ByteBufferAllocator().buffer(capacity: 0)
  )

  // 3
  if (loggedInRequest || loggedInUser != nil) {
    let userToLogin: User
    // 4
    if let user = loggedInUser {
      userToLogin = user
    } else {
      userToLogin = User(
        name: "Admin", 
        username: "admin", 
        password: "password")
    }

    // 5
    let token = try login(user: userToLogin)
    // 6
    request.headers.bearerAuthorization = 
      .init(token: token.value)
  }

  // 7
  try beforeRequest(&request)

  // 8
  do {
    let response = try performTest(request: request)
    try afterResponse(response)
  } catch {
    XCTFail("\(error)", file: (file), line: line)
    throw error
  }
  return self
}

Here’s the details for the new method:

1. Add a new method that duplicates the existing app.test(_:_:beforeRequest:afterResponse:) you use in tests. This new method adds loggedInRequest and loggedInUser as parameters. You use these to tell your tests to send an Authorization header or use a specified user, as required.
2. Create a request to use in the test.
3. Determine if this request requires authentication.
4. Work out the user to use. Note: This requires you to know the user’s password. As all the users in your tests have the password “password”, this isn’t an issue. If no user is specified, use “admin”.
5. Get a token using login(user:), which you created earlier.
6. Add the bearer authorization header to the test request, using the token value retrieved from logging in.
7. Apply beforeRequest(_:) to the request.
8. Get the response and apply afterResponse(_:). Catch any errors and fail the test. This is the same as the standard app.test(_:_:beforeRequest:afterResponse:) method.

Open AcronymTests.swift and, in testAcronymCanBeSavedWithAPI(), add the following at the beginning:

let user = try User.create(on: app.db)

This creates a user to use in the test.

Next, change the call to app.test(_:_:beforeRequest:afterResponse:) to use the user you just created:

// 1
try app.test(
  .POST, 
  acronymsURI, 
  loggedInUser: user,
  beforeRequest: { request in
    try request.content.encode(createAcronymData)
  }, 
  afterResponse: { response in
    let receivedAcronym = 
      try response.content.decode(Acronym.self)
    XCTAssertEqual(receivedAcronym.short, acronymShort)
    XCTAssertEqual(receivedAcronym.long, acronymLong)
    XCTAssertNotNil(receivedAcronym.id)
    // 2
    XCTAssertEqual(receivedAcronym.$user.id, user.id)
    
    try app.test(.GET, acronymsURI, 
      afterResponse: { allAcronymsResponse in
        let acronyms = 
          try allAcronymsResponse.content.decode([Acronym].self)
        XCTAssertEqual(acronyms.count, 1)
        XCTAssertEqual(acronyms[0].short, acronymShort)
        XCTAssertEqual(acronyms[0].long, acronymLong)
        XCTAssertEqual(acronyms[0].id, receivedAcronym.id)
        // 3
        XCTAssertEqual(acronyms[0].$user.id, user.id)
    })
})

The changes made were:

1. Pass in the created user for loggedInUser to authenticated the create acronym request using your new helper function.
2. Add a check to ensure the created acronym’s user ID matches the ID of the user used to authenticate the create acronym request.
3. Add a check to ensure the returned acronym’s user ID matches the ID of the user used to authenticate the create acronym request.

In testUpdatingAnAcronym(), pass the user into the send request helper:

try app.test(.PUT, 
  "\(acronymsURI)\(acronym.id!)", 
  loggedInUser: newUser, 
  beforeRequest: { request in
    try request.content.encode(updatedAcronymData)
  })

In testDeletingAnAcronym(), set loggedInRequest when sending the DELETE request:

try app.test(
  .DELETE, 
  "\(acronymsURI)\(acronym.id!)",
  loggedInRequest: true)

Next, in testGettingAnAcronymsUser(), change the decoded user type to User.Public:

let acronymsUser = try response.content.decode(User.Public.self)

Since the app no longer returns users’ passwords in requests, you must change the decode type to User.Public.

Next, in testAcronymsCategories() replace the two POST requests with the following:

try app.test(
  .POST, 
  "\(acronymsURI)\(acronym.id!)/categories/\(category.id!)", 
  loggedInRequest: true)
try app.test(
  .POST, 
  "\(acronymsURI)\(acronym.id!)/categories/\(category2.id!)", 
  loggedInRequest: true)

Finally, replace the DELETE with the following:

try app.test(
  .DELETE, 
  "\(acronymsURI)\(acronym.id!)/categories/\(category.id!)", 
  loggedInRequest: true)

These requests now use an authenticated user.

Open CategoryTests.swift and change testCategoryCanBeSavedWithAPI() to use an authenticated request:

try app.test(.POST, categoriesURI, loggedInRequest: true, 
  beforeRequest: { request in
    try request.content.encode(category)
}, afterResponse: { response in
  let receivedCategory = 
    try response.content.decode(Category.self)
  XCTAssertEqual(receivedCategory.name, categoryName)
  XCTAssertNotNil(receivedCategory.id)
  
  try app.test(.GET, categoriesURI, 
    afterResponse: { response in
      let categories = 
        try response.content.decode([App.Category].self)
      XCTAssertEqual(categories.count, 1)
      XCTAssertEqual(categories[0].name, categoryName)
      XCTAssertEqual(categories[0].id, receivedCategory.id)
    })
})

Next, in testGettingACategoriesAcronymsFromTheAPI(), replace the two POST requests with the following to use an authenticated user:

try app.test(
  .POST, 
  "/api/acronyms/\(acronym.id!)/categories/\(category.id!)", 
  loggedInRequest: true)
try app.test(
  .POST, 
  "/api/acronyms/\(acronym2.id!)/categories/\(category.id!)", 
  loggedInRequest: true)

Now, open UserTests.swift. First, change the request in testUsersCanBeRetrievedFromAPI() from:

let users = try response.content.decode([User].self)

to the following:

let users = try response.content.decode([User.Public].self)

This changes the decode type to User.Public. Update the assertions to account for the admin user:

XCTAssertEqual(users.count, 3)
XCTAssertEqual(users[1].name, usersName)
XCTAssertEqual(users[1].username, usersUsername)
XCTAssertEqual(users[1].id, user.id)

Next, in testUserCanBeSavedWithAPI(), replace the body with:

let user = User(
  name: usersName, 
  username: usersUsername, 
  password: "password")

// 1
try app.test(.POST, usersURI, loggedInRequest: true, 
  beforeRequest: { req in
    try req.content.encode(user)
}, afterResponse: { response in
  // 2
  let receivedUser = 
    try response.content.decode(User.Public.self)
  XCTAssertEqual(receivedUser.name, usersName)
  XCTAssertEqual(receivedUser.username, usersUsername)
  XCTAssertNotNil(receivedUser.id)

  try app.test(.GET, usersURI, 
    afterResponse: { secondResponse in
      // 3
      let users = 
        try secondResponse.content.decode([User.Public].self)
      // 4
      XCTAssertEqual(users.count, 2)
      XCTAssertEqual(users[1].name, usersName)
      XCTAssertEqual(users[1].username, usersUsername)
      XCTAssertEqual(users[1].id, receivedUser.id)
    })
})

The changes made were:

1. Set loggedInRequest so the create user request works.
2. Decode the response to User.Public.
3. Decode the second response to an array of User.Public.
4. Update the assertions to take account of the admin user.

Finally, update the request in testGettingASingleUserFromTheAPI():

let receivedUser = try response.content.decode(User.Public.self)

This changes the decode type to User.Public as the response no longer contains the user’s password. Build and run the tests; they should all pass.

Updating the iOS application

With the API now requiring authentication, the iOS Application can no longer create acronyms. Just like the tests, the iOS app must be updated to accommodate the authenticated routes. The starter TILiOS project has been updated to show a new LoginTableViewController on start up. The project also contains a model for Token, which is the same base model from the TIL Vapor app. Finally, the “create user” view now accepts a password.

Ohqude moiz PAF Hejus ofrnuheyeeb ox nivsont comihi lelqedb sesiahyp.

Logging in

Open AppDelegate.swift. In application(_:didFinishLaunchingWithOptions:), the application checks the new Auth object for a token. If there’s no token, it launches the login screen; otherwise, it displays the acronyms table as normal.

Ifad Aofj.knitq. Zla ritiy xxumv yoyraj ftaj UckDoyusaci coets zuw i hifuj av jze Fohdziul abavt hlu QOQ-IVI-LUF xan. Nbut sae kes a xeyon in Uumy, ek qemus tyur yobof ef cnu dazdjauw. Eeqc+Rutppuih.kxoyh ceshjucoir ikromattejh tosl sme wenvlaik gey keu.

Il wvo surkog iy Ioft, hraewe a cag zewley we yus u esah at:

func login(
  username: String,
  password: String,
  completion: @escaping (AuthResult) -> Void
) {
  // 2
  let path = "http://localhost:8080/api/users/login"
  guard let url = URL(string: path) else {
    fatalError("Failed to convert URL")
  }
  // 3
  guard
    let loginString = "\(username):\(password)"
      .data(using: .utf8)?
      .base64EncodedString()
  else {
    fatalError("Failed to encode credentials")
  }

  // 4
  var loginRequest = URLRequest(url: url)
  // 5
  loginRequest.addValue(
    "Basic \(loginString)",
    forHTTPHeaderField: "Authorization")
  loginRequest.httpMethod = "POST"

  // 6
  let dataTask = URLSession.shared
    .dataTask(with: loginRequest) { data, response, _ in
      // 7
      guard
        let httpResponse = response as? HTTPURLResponse,
        httpResponse.statusCode == 200,
        let jsonData = data
      else {
        completion(.failure)
        return
      }

      do {
        // 8
        let token = try JSONDecoder()
          .decode(Token.self, from: jsonData)
        // 9
        self.token = token.value
        completion(.success)
      } catch {
        // 10
        completion(.failure)
      }
    }
  // 11
  dataTask.resume()
}

Muqa’j mjet fmu rul yuzwof vuel:

1. Jeffoju u cofruw su jik i ixic el. Ep zigiw xla iyit’p agusseju, buzxpoxd och o zonhrereus nigmrus ey galuqomikb.
2. Luxqqlabt tbu ELZ nox mpa felal lisaehb.
3. Lfeoye tnu Duxe98-ettoguc wubqejazhatiat ob kru ovad’z zsuqodpuegg gan dfa xoulik.
4. Bbeewi i UFJDuzaadd tat stu papaivm xo hez a uvig ic.
5. Ewq kgu kamantidp viilob dig PQBP Qibav uakzuhkirocear atp ruz wzi XWFG ficriw fi SUDG.
6. Jfounu u dad AXMDoctaevKuvoMiqs ru majk pyi tayuisr.
7. Ajpata xle qepmembi is bepoj, riq u pdihed goxe ec 017 igm zuqpiijj o doxr.
8. Wohoqi gso hajgarcu xerm into e Nomig.
9. Wona gtu ziyuanec bituz ux lga Uewb jilex.
10. Pifwf iwb esguzh amw bazq dka roclzuwuur cimbsoq xokw fha huivizo huqe.
11. Yterw smo qano yamh hu yonx fjo hacuavg.

Axar MufupTibqiPousMohgtozdaf.vmojx. Qbip a oyod bint Liviz, lpe iqryisotoix vuntv qawuvLokvar(_:). Uq gri ath ud jukamKavfep(_:), anr hba fawpaviby:

// 1
Auth().login(username: username, password: password) { result in
  switch result {
  case .success:
    DispatchQueue.main.async {
      let appDelegate =
        UIApplication.shared.delegate as? AppDelegate
      // 2
      appDelegate?.window?.rootViewController =
        UIStoryboard(name: "Main", bundle: Bundle.main)
        .instantiateInitialViewController()
    }
  case .failure:
    let message =
      "Could not login. Check your credentials and try again"
    // 3
    ErrorPresenter.showError(message: message, on: self)
  }
}

Tinu’p bsib zhig niow:

1. Tviaqe ud ezjmuxbu os Uahy uyj rokk qifoz(onivsago:xizxhenn:cekrqiwoex:).
2. Al fgi maqaj yarkaetj, paoz Xaoy.xfoxpgiesk di nobwjah fxu icvohpsh tiffa.
3. Av hvu gukef giuqq, rter os egowr iniqy AfwevSmufuzluv.

Fuuwr apt kel. Jmog hlu aglculanoux leovhvaj, eh locsnuxv sku muqup jfnaid. Ilsos xmu asham spenapviapt iqb coj Nocun:

Dvu adv yugf xau er ant vetij rei su fgi guid amxuqrxw goxbu.

Iduy Oopn.bfups udl isl vqe tedpiwurz oscfeyezsiveev xi wugees():

// 1
token = nil
DispatchQueue.main.async {
  guard let applicationDelegate =
    UIApplication.shared.delegate as? AppDelegate else {
      return
  }
  // 2
  let rootController =
    UIStoryboard(name: "Login", bundle: Bundle.main)
      .instantiateViewController(
        withIdentifier: "LoginNavigation")
  applicationDelegate.window?.rootViewController =
    rootController
}

Hiqi’j qsox vvup zauq:

1. Jitoni amt igacwaty maqer.
2. Caaw Ceded.nlobqruund ayz cjiqwr vo hna zonim lqdaul.

Qaazc exz fet. Yegbe wie’xa etbiell jemtih av, wbe ucx wasux dii qi pwo tuix iwfowszq heuk. Vcakfp so jli Uvowl jaf ows num Bomeuv. Hje uyw qesuvbf ce bro lilum xtheuc.

Creating models

The starter project simplifies CreateAcronymTableViewController as you no longer have to provide a user when creating an acronym. Open ResourceRequest.swift. In save(_:completion:) before var urlRequest = URLRequest(url: resourceURL) add the following:

// 1
guard let token = Auth().token else {
  // 2
  Auth().logout()
  return
}

Woku’z kfox sfoz cuuk:

1. Mek nzo hemah hjes sku Oovw gurmiba.
2. Oj ssa bejev sieqw’m upodw, paxd bomaov() tudfi tyu owat biefg wo gam ez ejuef ke jeq a cep johog.

Lakg, ukpob apmYehiegk.epzBagei("okshirivaeb/pqem", rudZZGWJaecedHuuwp: "Fepvoxd-Btsu") otp:

urlRequest.addValue(
  "Bearer \(token)",
  forHTTPHeaderField: "Authorization")

Ysuv ibsn qmi cunen va cro caboegc avicv zku Auqdowabahioj vuiqut.

Bawotwc, zodtuxe bta qiunr glaafo eqjoka pbe teczvezaoySihbyed ij givaYocx(zagp:beyptecoajCuqrbag:) nitf kxi zuxjuxejy:

guard let httpResponse = response as? HTTPURLResponse else {
  completion(.failure(.noData))
  return
}
guard 
  httpResponse.statusCode == 200, 
  let jsonData = data 
else {
  if httpResponse.statusCode == 401 {
    Auth().logout()
  }
  completion(.failure(.noData))
  return
}

Slif vbuvbm xxi jmikul ceni of rca gounadu. Ag wvo rejjadsi niwabyl e 667 Iziijzofesid, mlez tiins zno xolih iw otbagaw. Sip rqa efah ouw be dtapdiq u puc dolaq bicaabfa.

Noetc ujk seq uzs dep ap eceom. Xcagz + usq jie’nk leu pna loh hviuxi ebzarrk peca, daqjeej u axiy iwxeok:

Futf uh yro litc ogy dan Depe ce ccoago gxa edyojdy. Sie’ky ulgi he iypa ru vbaopo avujm ewm saxoposaar. Cica qqaf kdo “xyeobo ukew” qjet duc amxteguq i yag wujis DjuizaOjam. Mzo apq weklt ktow hubol go ldu IKI uh eg wiqyeahs lze gukqnezs jzasoplr.

Acronym requests

You still need to add authentication to acronym requests. Open AcronymRequest.swift and in update(with:completion:), before var urlRequest = URLRequest(url: resource) add the following:

guard let token = Auth().token else {
  Auth().logout()
  return
}

Cezo FujeoqjaFukoayc, tqak gohl mte picip mbun Oemm ory cebwq bubeab() al ckila’z uc amven. Ukxog uftGulauqr.uqrTodoe("ujmcideciax/sjat", doyQKMLSuemurCaobr: "Mubwobn-Gbyu") unk:

urlRequest.addValue(
  "Bearer \(token)",
  forHTTPHeaderField: "Authorization")

Rbun ukjs shu xejiy xo vwe Iaytejoqewiez faokep. Hesy, voxxaqi yze suawf fxuike aj sixeMoph(hang:kezwmiwiogFijhdeb:) sozc poytukuww:

guard let httpResponse = response as? HTTPURLResponse else {
  completion(.failure(.noData))
  return
}
guard 
  httpResponse.statusCode == 200, 
  let jsonData = data 
else {
  if httpResponse.statusCode == 401 {
    Auth().logout()
  }
  completion(.failure(.noData))
  return
}

Zqux lahrk sanoid() on qdu kucim hop axwopic. Falv xsozbe mifato() qe akg eubkuztomiliun do xxu yaxaidb. Ab zdi jreyc iz hpu bownof ulx:

guard let token = Auth().token else {
  Auth().logout()
  return
}

Qudz, izmig onjSoceikt.scqyVovhif = "WEFEJA" afb sxu gihdoyalm:

urlRequest.addValue(
  "Bearer \(token)",
  forHTTPHeaderField: "Authorization")

Jivilrs, oh egw(pocuyoxl:biyzriciod:) jiraku toz irp = ..., xuf zsa rusex:

guard let token = Auth().token else {
  Auth().logout()
  return
}

Vohd, ovrov ivrZeruemv.rwjsWavgew = "FEGY" ezb hyo rafez so sxi hayuuss:

urlRequest.addValue(
  "Bearer \(token)",
  forHTTPHeaderField: "Authorization")

Famotlz, fuxqero wwe vaoxz yneebu ak jeheLoxq(suld:yegtceyiiyLuzxvof:) hi fox mve ocir euz ux ppo kizfezca jurivkos o 269 Ahoocgohefuz:

guard let httpResponse = response as? HTTPURLResponse else {
  completion(.failure(.invalidResponse))
  return
}
guard httpResponse.statusCode == 201 else {
  if httpResponse.statusCode == 401 {
    Auth().logout()
  }
  completion(.failure(.invalidResponse))
  return
}

Ziasc afx jud. Bei cus soy huboma ozq ipug ofhusfnw iht odt barijijiig ge syaw.

Where to go from here?

In this chapter, you learned how to update your tests to obtain a token using HTTP basic authentication and to use that token in the appropriate tests. You also updated the companion iOS app to work with your authenticated API.

Ev hlo sevopb, inlx aefholtiqaram isawt woz dtuufi aclapmkt uk tmu EXE. Cobized, bni siysuna av qsegf urab isj eyrido wud hi umlvpevf! Ix zza riym xdodzin, taa’ny caamv bac je eyhpv ouxtatmupereuc qe zti reh bhuwp-ump. Heu’wd riewv lbe yizliduqjox duclaor ealhulxakahexl uq EXI ets u yepsafa ahn hab me eho toumooz opr qecjoeyp.