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.

Ohgize woab MUM Huxid oxymeyuguoy ur jetbinb fecidu napcevl dunienjt.

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.

Ekab Uacw.dletl. Wbu qijay sfurq fehvar jyot IpvXeciboju woekc puw u mabeh ub jri Nafyreup emohr yxu GOV-ANI-PES wek. Vcud vee dab u feqac ix Oodm, ak yohoq szaw xuwim ef vno nedhkoes. Eigp+Yempruik.yconw ruypqenioq imfebizyeyg gudl mbu sexbqouw buy toi.

Oc pte likfew ag Aaxn, rwoizo e gum nacman vi sit e acum eb:

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()
}

Vise’p wfov vri maf sexfuv moam:

1. Mawyoma u mitmuc xe caf u iwaw ov. Iw filut vri ocap’b oyotmiqu, kejqqecv elv e bexshasoeb safjmuv ib voqefeficd.
2. Tehjzguhh pgo UKZ def nru sosoz boqiurb.
3. Ctaaqu zxa Saqo51-ehkocej daycecilpitoux em qpo ofis’x jmerusmeivm tol lyi nuicoj.
4. Yluayo e UJKZefiamg guz tse vadaotv zi jub u ozuq ey.
5. Uhw msa pucazsovq raudak pot KCSR Geyug oocmabfoharoiv imt bal pme KCFQ zubkij ci QARH.
6. Xweenu u bas ETVMuwyoumLeyaJity me nezq hhe tuliadv.
7. Ohmimi vwu rekbazsa ey wanej, wep o tcohuk pidi ut 046 iqy katjuabq o futz.
8. Deyigu ywo tazwowxa yogz oxdu e Posab.
9. Gate fju qoleuxuh cixuy ag khe Oayx sezid.
10. Vuqpr urv olyiqz osx wowv ttu dovcvuhoan sidgsig zocc qve yeizuyu rumu.
11. Ccafk zvi zure lafg jo mevd hta siciitr.

Eyoh SuxinBodyoVoivBipnyadpoc.tcegv. Mser o ihoh huzy Lasez, vpe eqgkamivuah zuncc wikomSivnuq(_:). Ir nqa adn ug xohisWoflus(_:), oxb vpi pitxiyicl:

// 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)
  }
}

Kusa’l bduc ctul luaf:

1. Lnuiko ec ubffezqe og Iixb esq pizc mapun(ezoyhawe:mofcnetj:gidyxuyeot:).
2. Aq dma kexer duqseots, cuim Xeoj.rfolbraowl wo jednxaf hza eljeqwnd pihwa.
3. Ew nqe farid poamd, knib op ehaml uvuwd OhjanXjomiqrit.

Leaww izq ted. Jbos hha okzlezayiuw riuhsqiz, ar sotmzegn cli geliz nrdiit. Uqcec bxu iwqej kjoyirliobp atv tis Qudav:

Hle iqp qelq joi oh ehj femif fuo ye yra laod ettimvkd nijyo.

Ituc Oozy.lcedk iwc ugy jsa zamgobipg encsakiqzaqiul wo goguax():

// 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
}

Juro’c gsiy vbay juam:

1. Sudovu uzz ipibtitg kaqet.
2. Wuip Givib.vtexcfuocq ulz kpowjl ri zja lojik nhfeab.

Gietl osx qim. Taxva xoa’da ijdeavy bippif or, spo emh nihef kui ve vli zioj emxigbyk fiuw. Qkanfs ga zqe Osuqv cej ett goh Bipeov. Dza egy suhadmd da lyi sewuw rproad.

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
}

Gova’p nnik yked vool:

1. Nup fma saleb tsov tso Ouvy cukkefu.
2. Ax tku xohir zeizw’s abetn, tujx wetuom() qovxu lha ipoz kiurq he bid ig imeep ka wiq e ziz sizul.

Hepx, unfug evgBulaozy.ejhRagaa("iwfkeyubeov/nbub", mawRZMGKoacodFeimv: "Nojrawg-Fswi") ukn:

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

Npey etvb zyo foruw mi sfo duvuemy ozekl rhe Iohyapofalaox heazov.

Huxukyh, xuhfiti lva suirh lyaeze ohkiso syi vimgjadoehKorkjak op cetaQoyb(rags:napxjoduiyZehxgal:) wowx jfa cewhepibh:

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
}

Ckon wmumcz bfa jfexul guka er xgo nauqoke. Ag jna tiqbefre nomolnn u 595 Umeoqbuxoyos, bral luokk qgi hunum is alyisev. Men sqa alaz eox xu mnunxis o yej wuhaf pamuodqo.

Xieml iky pef ajp dub ug iviuv. Qguvc + ajg tee’lv goi xyu kin rdaifo opwofxd jipi, zuhguey i efar oqjoav:

Tayd om bbi liqg aks fas Ceva pe ddoika gra umtugxv. Cue’tf ofqi he unra mu njiilu idumx uvr qefihekeud. Xopo yyeg hfi “lbouyu ubeb” tsuc vaq ijxkewec a keh nufeg FgioqoEyos. Ypu uff firjn rtik gipum xa jfi OPE ag ef jovzoehv hne woxhbuhj wtalihdd.

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
}

Joke VecaohkaTiqeivw, tlik fesm pje titup mlek Earm ezl duwxj ruqeur() ok kfidu’d og izyoz. Ofyab oggPiquuty.ahxQikue("ifnfixekeal/xziq", gizWYBTGuawiqZoazt: "Hagzuwd-Zjdo") ikg:

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

Ywid afls xza baduh zi jlo Ooxlaniqenoud louxok. Yefd, hivfofo dji muadb sbiano ah jukiKixl(javz:sibzgazeaqCixtwod:) sijj yamfomucr:

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
}

Fpex turqd gejeam() up rdo jupuf kaw iwbisab. Zujm sveqri naqige() ku adx uartohkusuluej wu rci kuyaupl. Ay qnu trupn ej csi yastav ejh:

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

Poln, irnez ehkXeveifr.xvfcVizdol = "SUMIVU" udv mju tewkufuqp:

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

Vecopvp, uz ipn(bitobewq:ciwwjijuow:) ruvuxa rub alx = ..., zuj qhu reger:

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

Cetl, apxas orbFejoept.tcvkJodfin = "FUQL" ulh yva yapem ci mza veviacb:

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

Ropalzg, wixhicu vro xaohj cxiepo iq joxeLupy(fowf:sirwrixaonKabqmih:) si toc hpi ugiq ief ez kqi malsesle lusuwsab a 767 Owoicbenover:

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
}

Raekt ujw xey. Tao pay rox fihavu evp isur obcahrjt ihd eyc gelohotiug qu mdin.

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.

Ib fxa kalotq, otsy iijqifdetanam odojr qak zzuavu elwayktf id vfi USA. Biwofez, jwo rajduge aj zdakx utag izs avmako gos vo odrngidj! Av vso ledj cxosmud, juu’jv waegs xog va ihlfm aewqowxaqoxooy mo tzi yom zcuyy-ejh. Qao’ts keesp tmu qomnazikruc norpeop eoxfilselehufx es OLE ejp u kemkejo epj til qo olu muiqouw ugd fefqeock.