19
API Authentication, Part 2
Written by Tim Condon
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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:
- Make the
username
parameter an optional string that defaults tonil
. - If a username is supplied, use it.
- If a username isn’t supplied, create a new, random one using
UUID
. This ensures the username is unique as required by the migration. - 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:
- Stop and remove the test PostgreSQL container, if it exists, so you start with a fresh database.
- 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:
- Add an extension to
XCTApplicationTester
, Vapor’s test wrapper aroundApplication
. - Define a log in method that takes
User
and returnsToken
. - Create a test POST request to /api/users/login — the log in URL — with empty values where needed.
- Set the HTTP Basic Authentication header using Vapor’s
BasicAuthorization
helpers. Note: The password here must be plaintext text, not the hashed password fromUser
. - Send the request to get the response.
- 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:
-
Add a new method that duplicates the existing
app.test(_:_:beforeRequest:afterResponse:)
you use in tests. This new method addsloggedInRequest
andloggedInUser
as parameters. You use these to tell your tests to send an Authorization header or use a specified user, as required. -
Create a request to use in the test.
-
Determine if this request requires authentication.
-
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”.
-
Get a token using
login(user:)
, which you created earlier. -
Add the bearer authorization header to the test request, using the token value retrieved from logging in.
-
Apply
beforeRequest(_:)
to the request. -
Get the response and apply
afterResponse(_:)
. Catch any errors and fail the test. This is the same as the standardapp.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:
- Pass in the created user for
loggedInUser
to authenticated the create acronym request using your new helper function. - Add a check to ensure the created acronym’s user ID matches the ID of the user used to authenticate the create acronym request.
- 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:
- Set
loggedInRequest
so the create user request works. - Decode the response to
User.Public
. - Decode the second response to an array of
User.Public
. - 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.
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.
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()
}
// 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)
}
}
// 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
}
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
}
urlRequest.addValue(
"Bearer \(token)",
forHTTPHeaderField: "Authorization")
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
}
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
}
urlRequest.addValue(
"Bearer \(token)",
forHTTPHeaderField: "Authorization")
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
}
guard let token = Auth().token else {
Auth().logout()
return
}
urlRequest.addValue(
"Bearer \(token)",
forHTTPHeaderField: "Authorization")
guard let token = Auth().token else {
Auth().logout()
return
}
urlRequest.addValue(
"Bearer \(token)",
forHTTPHeaderField: "Authorization")
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
}
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.