feat: token based authentication, authenticate route, token storage

projects/greenlight/internal/data/tokens.go

@@ -14,18 +14,20 @@ import (
 // Define constants for the token scope. For now we just define the scope "activation"
 // but we'll add additional scopes later in the book.
 const (
-	ScopeActivation = "activation"
+	ScopeActivation     = "activation"
+	ScopeAuthentication = "authentication" // Include a new authentication scope.
+
 )
 
 // Define a Token struct to hold the data for an individual token. This includes the
 // plaintext and hashed versions of the token, associated user ID, expiry time and
 // scope.
 type Token struct {
-	Plaintext string
-	Hash      []byte
-	UserID    int64
-	Expiry    time.Time
-	Scope     string
+	Plaintext string    `json:"token"`
+	Hash      []byte    `json:"-"`
+	UserID    int64     `json:"-"`
+	Expiry    time.Time `json:"expiry"`
+	Scope     string    `json:"-"`
 }
 
 func generateToken(userID int64, ttl time.Duration, scope string) (*Token, error) {

projects/greenlight/internal/data/users.go

@@ -39,6 +39,14 @@ type password struct {
 	hash      []byte
 }
 
+// Declare a new AnonymousUser variable.
+var AnonymousUser = &User{}
+
+// Check if a User instance is the AnonymousUser.
+func (u *User) IsAnonymous() bool {
+	return u == AnonymousUser
+}
+
 // The Set() method calculates the bcrypt hash of a plaintext password, and stores both
 // the hash and the plaintext versions in the struct.
 func (p *password) Set(plaintextPassword string) error {