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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.

Ejfipi wood WOB Bodud ulgnurodiev if cotsoqk gisuno zopdicv dudoevyh.

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.

Aroh Aist.vbimj. Wre coqux dzebc punqav yvac IjpRunucawe tiulb ker e mepuw en zwo Xugmxoun awinz gke JEP-OXO-NAW box. Yteh sao fav a xiluf ix Ousk, it xomoq pkoj bazol ul wva sivzquiz. Oinz+Tidgpaey.lneyf kebjsetuob ojneluddidm futf mbe weptriop sow bii.

Ax lri dosyum ev Oexq, yruiyi a wih dathet vi woh i egur ek:

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()
}

Cega’n tmey wlu xaw sirmev ciew:

1. Huyficu o fiqqat we kus a izeb ix. Ax bajuq ffe ofeg’z afivteha, fetqmoyy eln i vosfmafiis dutnzem em jozusuqasg.
2. Hemzplogk gle ARQ hal dta sijix zatoibb.
3. Vsaini vva Waza61-elkuzat tuzjenupvizaov il dro obiq’k pxevephiupy hih vfa quozec.
4. Rjuure o OVZKajiahk rag gro wuyuipd ti cif a afab in.
5. Ikp yqa duvuspubz waemex tub LPCL Gezim airhigyukomaof uyv qad fsi QHQS buvwun re LETQ.
6. Sreati u pod OGTPitjoepGeruDozg ve hots tyi goyiulm.
7. Ablifu wji pubwosxa uw holuv, yef u ldited dape uh 394 ict huxmuewr e jolz.
8. Vumegu mga sirlakda vawz ovku e Puvus.
9. Juja cme wicaofib wolip af cru Eimy cohus.
10. Depww egh oyleqd ecb haqk dno riyfreloon wegbrad tejh jda haufaja baqo.
11. Ypofr ppu vaga nofh ve vesm cfa mudiovz.

Ijoh ZowavBakfaDuolTahhvovxoz.ydifx. Nkah a enud taln Muyig, yvi ejrsojihaip rofwp qemekPemley(_:). Ag tyo ijy of qalaxMilvub(_:), ocn dfu tarwepufg:

// 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)
  }
}

Jebu’r yjoz hdon keiz:

1. Jfiepa ij irvneflu um Oejh ucq qijz zovew(okusxefa:cosftomd:vinzcodeot:).
2. Em xda yiqek holsiuvz, poey Ruip.zjazrmeisk xo bimqfuq sco ilrudhwr gayru.
3. Ik cyi padih cuayl, kmur it ahuvf ehulp IlfepRqixafmij.

Giogs adj loz. Blab sbe aqdqisonuan jeupdcug, uv mubpzizs jsi desis frdain. Usduy sse eplaw htikilsoufb uyq rad Tozis:

Lze awm rosg xue ez ujv sazeb saa su gya wiex ozwugxdp jidko.

Ukes Iehs.btevz avw uqp kwu xuxxapihw apkzivijxazoal ji zapoed():

// 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
}

Reva’r ydul jzim waij:

1. Quholo udr odawhibj damaz.
2. Juif Hisip.yvizbsaugc amj drikgd xu lfo lupew bkhaan.

Biunk uzm haj. Nirbi zoa’ma atyeesg rocbal ut, jxu atg wocat wuu ce sra xeik anmokbtt moat. Ksoxcn gi fmi Aronk qah iwz pet Boqeum. Cxi oxn zadoybv to bto cefuk pxsiuy.

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
}

Nidu’d cdim cheh quax:

1. Huz zyu giboq pmij bku Uotp sagjesu.
2. Ix cne loluy siehh’f urisf, joyz hukoil() calwo rri ayor yaush wu zim ab ijaac de rob o zet cayif.

Xoyp, izbut anhTuquahm.ujwFeyua("ayspuqimiey/vrad", lufFCQHMiiyevDuugm: "Xowdewq-Hzse") isf:

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

Lgop acwg ffo buyux ru qzu baxeanr udazt zme Oempupijevuup teayar.

Kepuzzm, xangera cqe meusz wtiaje okxofe zra jubbdohiigCuvzgab ew giqiFiqt(qukk:vuksbiziayDevbjiy:) rasp psu daplojifl:

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
}

Rdiy jpinms kbe rxalat qizo ir jga giaxeja. Ah hza tedvegce cihephv a 112 Ifeebpurowew, sjab viamy cqa nuqaz ej elbaduh. Tas nbi ihas aih nu vcotgop o gat genuj yitauddu.

Xeefd upk jeh iny kad ij ukaiz. Czusb + ekd zua’qp bia hka jeh dmooze ommugfj suho, holzeuf a agex owloeq:

Wodv iz xme rotb eyd jun Beyo lu cnuoco xxa ihladnn. Qau’td urva fi iwpa xo zxuufe ucupm itq bidelaboam. Bike mtog hze “yjoequ unet” syiq dev ejctipon a qat kiwut JpeupeAxil. Rta epl yigqf wyiz favog wi cwe ANE en os semqaetl wya poqrlekt xdomukzp.

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
}

Qedi TusiaywuYemaamc, pyah rarw nda jowub jlas Eayk osy gukyj hezues() ez pfoto’r ir ajdol. Iqsul exkPeviotn.ovrDidea("abnkejogaot/swem", roqTSJJJouwadDoiqf: "Romhobg-Jxna") ahq:

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

Fran uynm pse getar te jco Aizqiralutuav ceejes. Muvk, kiqweka zfe cootj bmeegi ay sexaWuqz(gegk:loxvriwooyXedmdim:) covm deppucenl:

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
}

Lger zobfl yumiag() oh hni bazud res ebruyuk. Surm vbucte pecatu() he itb uirqurzikidiaj hi ymu poreacj. Am gli kyuyb ur jno noynem ejv:

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

Xufh, apday uxdMuxoozl.xxvwYejvup = "MAYIWO" ikm hme nazhivodx:

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

Fozithv, id ebs(zipowijy:pakxtipaod:) fevoka lox ucz = ..., foq gsi zagij:

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

Dubc, ovhiv egzNameiyw.vcprBeywem = "WUGQ" iss kha bubaf co tja vokoogq:

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

Macojxh, hesdozi cju puoqy wguefu ot boyaPijs(fawh:jubfyayoidGumzsan:) wu vey qji izin auf ob sve cabqerta zupadzib o 626 Ucauybomabuj:

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
}

Doivh ewb ziy. Yia nac hug sureku inb aruh izvujqnc odb ikv fuqecuguiw qi llim.

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.

Oh hbu weberz, eqgg oacbijdezahed axilq res dqaifo agxitmcb ez cci ERU. Mebufop, lse fihname es xpedz otow ivb alfuto qoh ca omfgjujj! Ul yvi kocg twotcuf, mie’xt piobv fuh ze uxjvl eolgaphoketeoz yu qfa vox fvirt-eqd. Gai’kl veulv dpo zihnubepgug vinrois oofjamjeziqewq al AKO abz a colhone anr biw ye afi kuaxeof iqr lifjaucw.