feat: cancel user deletion

backend/routes/auth/undelete.go

@@ -0,0 +1,70 @@
+package auth
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"net/http"
+
+	"codeberg.org/u1f320/pronouns.cc/backend/log"
+	"codeberg.org/u1f320/pronouns.cc/backend/server"
+	"emperror.dev/errors"
+	"github.com/go-chi/render"
+	"github.com/mediocregopher/radix/v4"
+	"github.com/rs/xid"
+)
+
+func (s *Server) cancelDelete(w http.ResponseWriter, r *http.Request) error {
+	ctx := r.Context()
+	token := r.Header.Get("X-Delete-Token")
+	if token == "" {
+		return server.APIError{Code: server.ErrForbidden}
+	}
+
+	id, err := s.getUndeleteToken(ctx, token)
+	if err != nil {
+		log.Errorf("getting undelete token: %v", err)
+		return server.APIError{Code: server.ErrNotFound} // assume invalid token
+	}
+
+	err = s.DB.UndoDeleteUser(ctx, id)
+	if err != nil {
+		log.Errorf("executing undelete query: %v", err)
+	}
+
+	render.JSON(w, r, map[string]any{"success": true})
+	return nil
+}
+
+func undeleteToken() string {
+	b := make([]byte, 32)
+
+	_, err := rand.Read(b)
+	if err != nil {
+		panic(err)
+	}
+
+	return base64.RawURLEncoding.EncodeToString(b)
+}
+
+func (s *Server) saveUndeleteToken(ctx context.Context, userID xid.ID, token string) error {
+	err := s.DB.Redis.Do(ctx, radix.Cmd(nil, "SET", "undelete:"+token, userID.String(), "EX", "3600"))
+	if err != nil {
+		return errors.Wrap(err, "setting undelete key")
+	}
+	return nil
+}
+
+func (s *Server) getUndeleteToken(ctx context.Context, token string) (userID xid.ID, err error) {
+	var idString string
+	err = s.DB.Redis.Do(ctx, radix.Cmd(&idString, "GET", "undelete:"+token))
+	if err != nil {
+		return userID, errors.Wrap(err, "getting undelete key")
+	}
+
+	userID, err = xid.FromString(idString)
+	if err != nil {
+		return userID, errors.Wrap(err, "parsing ID")
+	}
+	return userID, nil
+}