[bugfix] Store LastModified for domain perm subs + send as If-Modified-Since (#3655)

internal/db/bundb/migrations/20241022153016_domain_permission_subscriptions/domainpermissionsubscription.go

@@ -33,6 +33,7 @@ type DomainPermissionSubscription struct {
 	FetchPassword         string    `bun:",nullzero"`
 	FetchedAt             time.Time `bun:"type:timestamptz,nullzero"`
 	SuccessfullyFetchedAt time.Time `bun:"type:timestamptz,nullzero"`
+	LastModified          time.Time `bun:"type:timestamptz,nullzero"`
 	ETag                  string    `bun:"etag,nullzero"`
 	Error                 string    `bun:",nullzero"`
 }

internal/db/bundb/migrations/20250119112746_domain_perm_sub_caching_tweaks.go

@@ -0,0 +1,76 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package migrations
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/uptrace/bun"
+)
+
+func init() {
+	up := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			// Bail if "last_modified"
+			// column already created.
+			if exists, err := doesColumnExist(
+				ctx,
+				tx,
+				"domain_permission_subscriptions",
+				"last_modified",
+			); err != nil {
+				return err
+			} else if exists {
+				return nil
+			}
+
+			// Derive column definition.
+			var permSub *gtsmodel.DomainPermissionSubscription
+			permSubType := reflect.TypeOf(permSub)
+			colDef, err := getBunColumnDef(tx, permSubType, "LastModified")
+			if err != nil {
+				return fmt.Errorf("error making column def: %w", err)
+			}
+
+			log.Info(ctx, "adding domain_permission_subscriptions.last_modified column...")
+			if _, err := tx.
+				NewAddColumn().
+				Model(permSub).
+				ColumnExpr(colDef).
+				Exec(ctx); err != nil {
+				return fmt.Errorf("error adding column: %w", err)
+			}
+
+			return nil
+		})
+	}
+
+	down := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			return nil
+		})
+	}
+
+	if err := Migrations.Register(up, down); err != nil {
+		panic(err)
+	}
+}