feat(download): persist poster and backdrop images (#6232)

database/versions/a8c4e2f6b1d9_2_2_15.py

@@ -0,0 +1,42 @@
+"""2.2.15
+为下载历史增加海报字段
+
+Revision ID: a8c4e2f6b1d9
+Revises: f7b2d5c9a301
+Create Date: 2026-08-03
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "a8c4e2f6b1d9"
+down_revision = "f7b2d5c9a301"
+branch_labels = None
+depends_on = None
+
+
+def _has_column(table_name: str, column_name: str) -> bool:
+    """检查数据表是否已存在指定字段。"""
+    inspector = sa.inspect(op.get_bind())
+    if table_name not in inspector.get_table_names():
+        return False
+    return any(
+        column["name"] == column_name
+        for column in inspector.get_columns(table_name)
+    )
+
+
+def upgrade() -> None:
+    """为下载历史增加可空海报字段。"""
+    if not _has_column("downloadhistory", "poster"):
+        op.add_column(
+            "downloadhistory",
+            sa.Column("poster", sa.String(), nullable=True),
+        )
+
+
+def downgrade() -> None:
+    """移除下载历史海报字段。"""
+    if _has_column("downloadhistory", "poster"):
+        op.drop_column("downloadhistory", "poster")