The document describes a sign in service that validates a client, authenticates a user, and issues an access token. It defines a SignInService class that takes functions for validating clients, authenticating users, and creating access tokens. The signIn method uses these functions in a for comprehension to validate the client, authenticate the user, and create an access token, returning a Future[AccessToken]. It also shows refactoring the service to take functions instead of dependencies and moving the signIn method to a static object.

8. Actually, I’m a
Spy Turtle.

9. Actually, I’m a
Spy Turtle.
QW
I recommend Uncle
Bob’s “The Little
Mocker” post

14. WS

15. Validate client
Authenticate user
Issue access token
clientId, clientSecret
email, password
access token
Client
User

16. class SignInService(clientService: ClientService,
authenticatorService: AuthentictorService,
accessTokenService: TokenService
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- clientService.validateClient(clientId, clientSecret)
user <- authenticatorService.authenticateUser(email, password)
accessToken <- accessTokenService.createAccessToken(user.id,
client.id)
} yield (accessToken)
}

17. class SignInService(clientService: ClientService,
authenticatorService: AuthentictorService,
accessTokenService: TokenService
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- clientService.validateClient(clientId, clientSecret)
user <- authenticatorService.authenticateUser(email, password)
accessToken <- accessTokenService.createAccessToken(user.id,
client.id)
} yield (accessToken)
}

18. class SignInService(clientService: ClientService,
authenticatorService: AuthentictorService,
accessTokenService: TokenService
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- clientService.validateClient(clientId, clientSecret)
user <- authenticatorService.authenticateUser(email, password)
accessToken <- accessTokenService.createAccessToken(user.id,
client.id)
} yield (accessToken)
}

19. class SignInService(clientService: ClientService,
authenticatorService: AuthentictorService,
accessTokenService: TokenService
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- clientService.validateClient(clientId, clientSecret)
user <- authenticatorService.authenticateUser(email, password)
accessToken <- accessTokenService.createAccessToken(user.id,
client.id)
} yield (accessToken)
}
T

20. class SignInService(clientService: ClientService,
authenticatorService: AuthentictorService,
accessTokenService: TokenService
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- clientService.validateClient(clientId, clientSecret)
user <- authenticatorService.authenticateUser(email, password)
accessToken <- accessTokenService.createAccessToken(user.id,
client.id)
} yield (accessToken)
}

21. class ClientService(jsonClient: JsonClient) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
jsonClient.getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)

22. class ClientService(jsonClient: JsonClient) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
jsonClient.getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)

23. class ClientService(jsonClient: JsonClient) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
jsonClient.getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)

24. class ClientService(jsonClient: JsonClient) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
jsonClient.getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)

25. class ClientService(jsonClient: JsonClient) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
jsonClient.getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)
EL

26. class ClientService(jsonClient: JsonClient) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
jsonClient.getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)

27. "returns client if credentials match" in new Scope {
val jsonClient = mock[JsonClient]
val clientService = new ClientService(jsonClient)
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...))
when(jsonClient.get(Path() / "clients" / "clientId")
.thenReturn(Future.value(jsonResponse))
clientService.validateClient("clientId", "secret")
==== Client(5)
}

28. "returns client if credentials match" in new Scope {
val jsonClient = mock[JsonClient]
val clientService = new ClientService(jsonClient)
val jsonResponse = JsonResponse(OkStatus,Json.fromString(...))
when(jsonClient.get(Path() / "clients" / "clientId")
.thenReturn(Future.value(jsonResponse))
clientService.validateClient("clientId", "secret")
==== Client(5)
}

29. "returns client if credentials match" in new Scope {
val jsonClient = mock[JsonClient]
val clientService = new ClientService(jsonClient)
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
when(jsonClient.get(Path() / "clients" / "clientId")
.thenReturn(Future.value(jsonResponse))
clientService.validateClient("clientId", "secret")
==== Client(5)
}

30. "returns client if credentials match" in new Scope {
val jsonClient = mock[JsonClient]
val clientService = new ClientService(jsonClient)
val jsonResponse = JsonResponse(OkStatus,Json.fromString(...))
when(jsonClient.get(Path() / "clients" / "clientId")
.thenReturn(Future.value(jsonResponse))
clientService.validateClient("clientId", "secret")
==== Client(5)
}

31. "returns client if credentials match" in new Scope {
val jsonClient = mock[JsonClient]
val clientService = new ClientService(jsonClient)
val jsonResponse = JsonResponse(OkStatus,Json.fromString(...))
when(jsonClient.get(Path() / "clients" / "clientId")
.thenReturn(Future.value(jsonResponse))
clientService.validateClient("clientId", "secret")
==== Client(5)
}

32. "returns client if credentials match" in new Scope {
val jsonClient = mock[JsonClient]
val clientService = new ClientService(jsonClient)
val jsonResponse = JsonResponse(OkStatus,Json.fromString(...))
when(jsonClient.get(Path() / "clients" / "clientId")
.thenReturn(Future.value(jsonResponse))
clientService.validateClient("clientId", "secret")
==== Client(5)
}
B

33. F

34. class ClientService(jsonClient: JsonClient) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
jsonClient.getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)

35. class ClientService(getJson: (Path) => Future[JsonResponse]) {
def validateClient(clientId: String, clientSecret: String):
Future[Client]={
getJson(
Path() / "clients" / clientId
).map {
case JsonResponse(OkStatus, json, _, _) => {
val id = (json "id").as[Long]
val secret = (json "secret").as[String]
if (secret != clientSecret) {
throw new Exception("Client doesn't match")
}
Client(id)
:I

36. val jsonClient = JsonClient(host)
val clientService = new ClientService(jsonClient.getJson)

37. val jsonClient = JsonClient(host)
val clientService = new ClientService(jsonClient.getJson)

38. "returns client if credentials match" in new Scope {
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
val clientService = new ClientService(_ => Future.value(jsonResponse))
clientService.validateClient("clientId", "secret") ==== Client(5)
}

39. "returns client if credentials match" in new Scope {
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
val clientService = new ClientService(_ => Future.value(jsonResponse))
clientService.validateClient("clientId", "secret") ==== Client(5)
}

40. "returns client if credentials match" in new Scope {
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
val clientService = new ClientService(_ => Future.value(jsonResponse))
clientService.validateClient("clientId", "secret") ==== Client(5)
}

41. "returns client if credentials match" in new Scope {
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
val clientService = new ClientService(_ => Future.value(jsonResponse))
clientService.validateClient("clientId", "secret") ==== Client(5)
}

42. "returns client if credentials match" in new Scope {
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
val clientService = new ClientService(_ => Future.value(jsonResponse))
clientService.validateClient("clientId", "secret") ==== Client(5)
}
!E

43. when(jsonClient.getJson(Path()/"clients"/"clientId")
.thenReturn(Future.value(jsonResponse))
:CA

44. "returns client if credentials match" in new Scope {
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
var arg: Option[Path] = None
val getJson = (path:Path) => {
arg = Some(path)
Future.value(jsonResponse)
}
val clientService = new ClientService(getJson)
clientService.validateClient("clientId", "secret")) ==== Client(5)
arg ==== Some(Path() / "clients" / "clientId")
}

45. "returns client if credentials match" in new Scope {
val jsonResponse = JsonResponse(OkStatus, Json.fromString(...)
var arg: Option[Path] = None
val getJson = (path:Path) => {
arg = Some(path)
Future.value(jsonResponse)
}
val clientService = new ClientService(getJson)
clientService.validateClient("clientId", "secret")) ==== Client(5)
arg ==== Some(Path() / "clients" / "clientId")
}
:S

46. :MF

47. –Martin Fowler
http://martinfowler.com/articles/mocksArentStubs.html#TheDifferenceBetweenMocksAndStubs

48. ~Martin Fowler
http://martinfowler.com/articles/mocksArentStubs.html#TheDifferenceBetweenMocksAndStubs

49. ~Martin Fowler
http://martinfowler.com/articles/mocksArentStubs.html#TheDifferenceBetweenMocksAndStubs
intermediate state

50. ~Martin Fowler
http://martinfowler.com/articles/mocksArentStubs.html#TheDifferenceBetweenMocksAndStubs
Side effects

51. Yay! No more
mock soup
FSB

52. Validate client
Authenticate user
Issue access token
clientId, clientSecret
email, password
access token
Client
User

53. class SignInService(
clientService: ClientService,
authenticatorService: AuthentictorService,
accessTokenService: TokenService
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- clientService.validateClient(clientId, clientSecret)
user <- authenticatorService.authenticateUser(email, password)
accessToken <- accessTokenService.createAccessToken(user.id,
client.id)
} yield (accessToken)
}

54. class SignInService(
clientService: ClientService,
authenticatorService: AuthentictorService,
accessTokenService: TokenService
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- clientService.validateClient(clientId, clientSecret)
user <- authenticatorService.authenticateUser(email, password)
accessToken <- accessTokenService.createAccessToken(user.id,
client.id)
} yield (accessToken)
}

55. class SignInService(
validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken]
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}
:FO

56. object SignIn {
def signIn(validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken])
(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}
}

57. object SignIn {
def signIn(validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken])
(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}
}

58. :C
object SignIn {
def signIn(validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken])
(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}
}

59. class SignInService(
validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken]
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}
:N

60. class SignInService(
validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken]
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}

61. class SignInService(
validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken]
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}

62. class SignInService(
validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken]
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}
:IJA

63. class SignInService(
validateClient: (String, String) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken]
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}

64. class SignInService(
validateClient: (ClientId, ClientSecret) => Future[Client],
authenticateUser: (String, String) => Future[User],
createAccessToken: (Long, Long) => Future[AccessToken]
) {
def signIn(clientId: String, clientSecret: String, email: String,
password: String): Future[AccessToken] = {
for {
client <- validateClient(clientId, clientSecret)
user <- authenticateUser(email, password)
accessToken <- createAccessToken(user.id, client.id)
} yield (accessToken)
}
:W

65. object SignInApi extends FinagleBasedServer with AppConfigComponent{
val clientsJsonClient = JsonClient(host)
val tokensClient = JsonClient(host)
val dbClient = MySqlClient(dbconfig)
val passwordsRepo = new PasswordRepository(dbClient.prepare, dbClient.execute)
val clientService = new ClientService(clientsJsonClient.get)
val authenticatorService = new AuthentictorService(passwordsRepo.getPassword)
val tokenService = new TokenService(tokensClient.get)
val signInService = new SignInService(
clientService.validateClient,
authenticatorService.authenticateUser,
tokenService.createAccessToken
)
val signInHandler = new SignInHandler(signInService.signIn)
override def createRoutes(httpServer: HttpServer): Unit = {
httpServer.register("/sign-in", signInHandler)
}
}
MSEV

66. trait JsonClients {
self: ConfigComponent =>
val clientsJsonClient = JsonClient(config.clientsHost)
val tokensClient = JsonClient(config.tokensHost)
}

67. trait Repositories {
self: ConfigComponent =>
val dbClient = MySqlClient(config.dbHost, config.dbName, ...)
val passwordsRepo = new PasswordRepository(dbClient.prepare,
dbClient.execute)
}

68. trait Repositories {
self: ConfigComponent =>
val dbClient = MySqlClient(config.dbHost, config.dbName, ...)
val passwordRepo = new PasswordRepository(dbClient.prepare,
dbClient.execute)
}

69. trait Services extends JsonClients with Repositories {
self: ConfigComponent =>
val clientService = new ClientService(clientsJsonClient.get)
val authenticatorService = new AuthentictorService(passwordsRepo.getPassword
val tokenService = new TokenService(tokensClient.get)
val signInService = new SignInService(
clientService.validateClient,
authenticatorService.authenticateUser,
tokenService.createAccessToken
)
}

70. trait Services extends JsonClients with Repositories {
self: ConfigComponent =>
val clientService = new ClientService(clientsJsonClient.get)
val authenticatorService = new AuthentictorService(passwordsRepo.getPassword
val tokenService = new TokenService(tokensClient.get)
val signInService = new SignInService(
clientService.validateClient,
authenticatorService.authenticateUser,
tokenService.createAccessToken
)
}

71. trait Services extends JsonClients with Repositories {
self: ConfigComponent =>
val clientService = new ClientService(clientsJsonClient.get)
val authenticatorService = new AuthentictorService(passwordsRepo.getPassword
val tokenService = new TokenService(tokensClient.get)
val signInService = new SignInService(
clientService.validateClient,
authenticatorService.authenticateUser,
tokenService.createAccessToken
)
}

72. trait Services extends JsonClients with Repositories {
self: ConfigComponent =>
val clientService = new ClientService(clientsJsonClient.get)
val authenticatorService = new AuthentictorService(passwordsRepo.getPassword
val tokenService = new TokenService(tokensClient.get)
val signInService = new SignInService(
clientService.validateClient,
authenticatorService.authenticateUser,
tokenService.createAccessToken
)
}

73. object ExampleSignInApi extends FinagleBasedServer
with ConfigComponent
with Services{
val signInHandler = new SignInHandler(signInService.signIn)
override def createRoutes(httpServer: HttpServer): Unit = {
httpServer.register("/sign-in", signInHandler)
}
}
S

74. object ExampleSignInApi extends FinagleBasedServer
with ConfigComponent
with Services{
val signInHandler = new SignInHandler(signInService.signIn)
override def createRoutes(httpServer: HttpServer): Unit = {
httpServer.register("/sign-in", signInHandler)
}
}
S

75. H

76. ●
●
●
●
E

77. def getUser(id: Int): Reader[DB,User]
= Reader( (db:DB) => User("duana") )
def getTracks(user: User): Reader[DB,Track]
= Reader( (db:DB) => Track(42))
val myProgram: Reader[DB,String] =
for {
user <- getUser(123)
track <- getTracks(user)
} yield track.toString
myProgram.perform(db)

78. ●
●
●

79. ●

80. TE

81. Manual DI Magic DI
● Requires discipline
● Static check
● No framework or fancy
language features to learn
● Boring
● Enforces consistency
● Runtime check?
● Problems can be hare-y
● Slick

82. U
Manual DI Magic DI (Framework)
● Requires discipline
● Static check
● No framework or fancy
language features to learn
● Boring
● Enforces consistency
● Runtime check?
● Problems can be hare-y
● Slick
Stop spreading
the news!

83. :L
Manual DI Magic DI (Framework)
● Requires discipline
● Static check
● No framework or fancy
language features to learn
● Boring
● Enforces consistency
● Runtime check?
● Problems can be hare-y
● Slick

84. Manual DI Magic DI (Framework)
● Requires discipline
● Static check
● No framework or fancy
language features to learn
● Boring
● Enforces consistency
● Runtime check?
● Problems can be hare-y
● Slick

85. Manual DI Magic DI (Framework)
● Requires discipline
● Static check
● No framework or fancy
language features to learn
● Boring
● Enforces consistency
● Runtime check?
● Problems can be hare-y
● Slick
:M

87. def makeTalk(
askChrisBerkhout: (Talk) => Better[Talk],
askAaronLevinAboutFP: (None) => Some[Idea],
askBrianGuthrieAboutClojure: (Idea) => Better[Idea]
)(ideas: Talk): Better[Talk]
makeTalk(..) was invoked by com.thoughtworks.Birgitta

88. @ThoughtWorks, @SoundCloudDev
@chrisberkhout, @aaronmblevin, @bguthrie, @birgitta410,
@davcamer, @rentalcustard
@theophani, @ellenkoenig, @harrydeanhudson
Questions @starkcoffee