11 KiB
Authentication using Fluent
Fluent builds on Vapor's Authentication API to provide an easy, customizable way to do user authentication using database models.
Introduction
Fluent defines two protocols ModelUser and ModelUserToken which can be added to your existing models. Conforming your models to these protocols allows for the creation of authenticators which generate middleware for protecting endpoints.
ModelUserToken authenticates with a Bearer token. This is what you use to protect most of your endpoints. ModelUser authenticates with username and password and is used by a single endpoint for generating tokens.
This guide assumes you are familiar with Fluent and have successfully configured your app to use a database. If you are new to Fluent, start with the overview.
User
To start, you will need a model representing the user that will be authenticated. For this guide, we'll be using the following model, but you are free to use an existing model.
import Fluent
import Vapor
final class User: Model, Content {
static let schema = "users"
@ID(key: .id)
var id: UUID?
@Field(key: "name")
var name: String
@Field(key: "email")
var email: String
@Field(key: "password_hash")
var passwordHash: String
init() { }
init(id: UUID? = nil, name: String, email: String, passwordHash: String) {
self.id = id
self.name = name
self.email = email
self.passwordHash = passwordHash
}
}
The model must be able to store a username, in this case an email, and a password hash. The corresponding migration for this example model is here:
import Fluent
import Vapor
extension User {
struct Migration: Fluent.Migration {
var name: String { "CreateUser" }
func prepare(on database: Database) -> EventLoopFuture<Void> {
database.schema("users")
.id()
.field("name", .string, .required)
.field("email", .string, .required)
.field("password_hash", .string, .required)
.create()
}
func revert(on database: Database) -> EventLoopFuture<Void> {
database.schema("users").delete()
}
}
}
Don't forget to add the migration to app.migrations.
app.migrations.add(User.Migration())
The first thing you will need is an endpoint to create new users. Let's use POST /users. Create a Content struct representing the data this endpoint expects.
import Vapor
extension User {
struct Create: Content {
var name: String
var email: String
var password: String
var confirmPassword: String
}
}
If you like, you can conform this struct to Validatable to add validation requirements.
import Vapor
extension User.Create: Validatable {
static func validations(_ validations: inout Validations) {
validations.add("name", as: String.self, is: !.empty)
validations.add("email", as: String.self, is: .email)
validations.add("password", as: String.self, is: .count(8...))
}
}
Now you can create the POST /users endpoint.
app.post("users") { req -> EventLoopFuture<User> in
try User.Create.validate(req)
let create = try req.content.decode(User.Create.self)
guard create.password == create.confirmPassword else {
throw Abort(.badRequest, reason: "Passwords did not match")
}
let user = try User(
name: create.name,
email: create.email,
passwordHash: Bcrypt.hash(create.password)
)
return user.save(on: req.db)
.map { user }
}
This endpoint validates the incoming request, decodes the User.Create struct, and checks that the passwords match. It then uses the decoded data to create a new User and saves it to the database. The plaintext password is hashed using Bcrypt before saving to the database.
Build and run the project, making sure to migrate the database first, then use the following request to create a new user.
POST /users HTTP/1.1
Content-Length: 97
Content-Type: application/json
{
"name": "Vapor",
"email": "test@vapor.codes",
"password": "secret",
"confirmPassword": "secret"
}
Authenticator
Now that you have a user model and an endpoint to create new users, let's conform the model to ModelUser. This will allow for the model to be authenticated using username and password.
import Fluent
import Vapor
extension User: ModelUser {
static let usernameKey = \User.$email
static let passwordHashKey = \User.$passwordHash
func verify(password: String) throws -> Bool {
try Bcrypt.verify(password, created: self.passwordHash)
}
}
This extension adds ModelUser conformance to User. The first two properties specify which fields should be used for storing the username and password hash respectively. The \ notation creates a key path to the fields that Fluent can use to access them.
The last requirement is a method for verifying plaintext passwords sent in the Basic authentication header. Since we're using Bcrypt to hash the password during signup, we'll use Bcrypt to verify that the supplied password matches the stored password hash.
Now that the User conforms to ModelUser, we can create a middleware from the authenticator to protect the login route.
let passwordProtected = app.grouped(User.authenticator().middleware())
passwordProtected.post("login") { req -> User in
try req.auth.require(User.self)
}
ModelUser adds a static method authenticator for creating an authenticator. You can then use middleware to generate a middleware from the authenticator.
Test that this route works by sending the following request.
POST /login HTTP/1.1
Authorization: Basic dGVzdEB2YXBvci5jb2RlczpzZWNyZXQ=
This request passes the username test@vapor.codes and password secret via the Basic authentication header. You should see the previously created user returned.
While you could theoretically use Basic authentication to protect all of your endpoints, it's recommended to use a separate token instead. This minimizes how often you must send the user's sensitive password over the Internet. It also makes authentication much faster since you only need to perform password hashing during login.
User Token
Create a new model for representing user tokens.
import Fluent
import Vapor
final class UserToken: Model, Content {
static let schema = "user_tokens"
@ID(key: .id)
var id: UUID?
@Field(key: "value")
var value: String
@Parent(key: "user_id")
var user: User
init() { }
init(id: UUID? = nil, value: String, userID: User.IDValue) {
self.id = id
self.value = value
self.$user.id = userID
}
}
This model must have a value field for storing the token's unique string. It must also have a parent-relation to the user model. You may add additional properties to this token as you see fit, such as an expiration date.
Next, create a migration for this model.
import Fluent
extension UserToken {
struct Migration: Fluent.Migration {
var name: String { "CreateUserToken" }
func prepare(on database: Database) -> EventLoopFuture<Void> {
database.schema("user_tokens")
.id()
.field("value", .string, .required)
.field("user_id", .uuid, .required, .references("users", "id"))
.unique(on: "value")
.create()
}
func revert(on database: Database) -> EventLoopFuture<Void> {
database.schema("user_tokens").delete()
}
}
}
Notice that this migration makes the value field unique. It also creates a foreign key reference between the user_id field and the users table.
Don't forget to add the migration to app.migrations.
app.migrations.add(UserToken.Migration())
Finally, add a method on User for generating a new token. This method will be used during login.
extension User {
func generateToken() throws -> UserToken {
try .init(
value: [UInt8].random(count: 16).base64,
userID: self.requireID()
)
}
}
Here we're using [UInt8].random(count:) to generate a random token value. For this example, 16 bytes, or 128 bits, of random data are being used. You can adjust this number as you see fit. The random data is then base-64 encoded to make it easy to transmit in HTTP headers.
Now that you can generate user tokens, update the POST /login route to create and return a token.
let passwordProtected = app.grouped(User.authenticator().middleware())
passwordProtected.post("login") { req -> EventLoopFuture<UserToken> in
let user = try req.auth.require(User.self)
let token = try user.generateToken()
return token.save(on: req.db)
.map { token }
}
Test that this route works by using the same login request from above. You should now get a token upon logging in that looks something like:
8gtg300Jwdhc/Ffw784EXA==
Hold onto the token you get as we'll use it shortly.
Authenticator
Conform UserToken to ModelUserToken. This will allow for tokens to authenticate your User model.
import Vapor
import Fluent
extension UserToken: ModelUserToken {
static let valueKey = \UserToken.$value
static let userKey = \UserToken.$user
var isValid: Bool {
true
}
}
The first protocol requirement specifies which field stores the token's unique value. This is the value that will be sent in the Bearer authentication header. The second requirement specifies the parent-relation to the User model. This is how Fluent will look up the authenticated user.
The final requirement is an isValid boolean. If this is false, the token will be deleted from the database and the user will not be authenticated. For simplicity, we'll make the tokens eternal by hard-coding this to true.
Now that the token conforms to ModelUserToken, you can create an authenticator and middleware for protecting routes.
Create a new endpoint GET /me for getting the currently authenticated user.
let tokenProtected = app.grouped(UserToken.authenticator().middleware())
tokenProtected.get("me") { req -> User in
try req.auth.require(User.self)
}
Similar to User, UserToken now has a static authenticator() method that can generate a middleware with middleware(). The middleware will attempt to find a matching UserToken using the value provided in the Bearer authentication header. If it finds a match, it will fetch the related User and authenticate it.
Test that this route works by sending the following HTTP request where the token is the value you saved from the POST /login request.
GET /me HTTP/1.1
Authorization: Bearer <token>
You should see the authenticated User returned.