Add other auth commands

Author: theandrew168

backend/command/auth.go

@@ -0,0 +1,111 @@
+package command
+
+import (
+	"errors"
+	"log/slog"
+	"time"
+
+	"github.com/theandrew168/bloggulus/backend/model"
+	"github.com/theandrew168/bloggulus/backend/postgres"
+	"github.com/theandrew168/bloggulus/backend/repository"
+	"github.com/theandrew168/bloggulus/backend/timeutil"
+	"github.com/theandrew168/bloggulus/backend/web/util"
+)
+
+var ErrSessionNotFound = errors.New("session not found")
+
+func (cmd *Command) SignIn(username string) (string, error) {
+	// NOTE: Handling state outside the transaciton is the exception, not the rule.
+	// This is a special case where a command needs to return a value (the session ID).
+	var sessionID string
+	err := cmd.repo.WithTransaction(func(tx *repository.Repository) error {
+		account, err := tx.Account().ReadByUsername(username)
+		if err != nil {
+			if !errors.Is(err, postgres.ErrNotFound) {
+				return err
+			}
+
+			// We need to create a new account at this point.
+			account, err = model.NewAccount(username)
+			if err != nil {
+				return err
+			}
+
+			err = tx.Account().Create(account)
+			if err != nil {
+				return err
+			}
+
+			slog.Info("account created",
+				"account_id", account.ID(),
+			)
+		}
+
+		// Create a new session for the account.
+		var session *model.Session
+		session, sessionID, err = model.NewSession(account, util.SessionCookieTTL)
+		if err != nil {
+			return err
+		}
+
+		err = tx.Session().Create(session)
+		if err != nil {
+			return err
+		}
+
+		slog.Info("account signed in",
+			"account_id", account.ID(),
+			"session_id", session.ID(),
+		)
+
+		return nil
+	})
+
+	return sessionID, err
+}
+
+func (cmd *Command) SignOut(sessionID string) error {
+	return cmd.repo.WithTransaction(func(tx *repository.Repository) error {
+		session, err := tx.Session().ReadBySessionID(sessionID)
+		if err != nil {
+			if !errors.Is(err, postgres.ErrNotFound) {
+				return err
+			}
+
+			return ErrSessionNotFound
+		}
+
+		err = tx.Session().Delete(session)
+		if err != nil {
+			if !errors.Is(err, postgres.ErrNotFound) {
+				return err
+			}
+
+			return ErrSessionNotFound
+		}
+
+		return nil
+	})
+}
+
+func (cmd *Command) DeleteExpiredSessions(now time.Time) error {
+	return cmd.repo.WithTransaction(func(tx *repository.Repository) error {
+		now := timeutil.Now()
+		expiredSessions, err := tx.Session().ListExpired(now)
+		if err != nil {
+			return err
+		}
+
+		for _, session := range expiredSessions {
+			err := tx.Session().Delete(session)
+			if err != nil {
+				// Ignore any "not found" errors here.
+				if !errors.Is(err, postgres.ErrNotFound) {
+					return err
+				}
+			}
+		}
+
+		return nil
+	})
+}