package main import ( "context" "database/sql" "errors" ) func (db *database) cachePersistently(key string, data []byte) error { return db.cachePersistentlyContext(context.Background(), key, data) } func (db *database) cachePersistentlyContext(ctx context.Context, key string, data []byte) error { if db == nil { return errors.New("database is nil") } _, err := db.ExecContext(ctx, "insert or replace into persistent_cache(key, data, date) values(@key, @data, @date)", sql.Named("key", key), sql.Named("data", data), sql.Named("date", utcNowString())) return err } func (db *database) retrievePersistentCache(key string) (data []byte, err error) { return db.retrievePersistentCacheContext(context.Background(), key) } func (db *database) retrievePersistentCacheContext(c context.Context, key string) (data []byte, err error) { if db == nil { return nil, errors.New("database is nil") } d, err, _ := db.pc.Do(key, func() (any, error) { if row, err := db.QueryRowContext(c, "select data from persistent_cache where key = @key", sql.Named("key", key)); err != nil { return nil, err } else { err = row.Scan(&data) if errors.Is(err, sql.ErrNoRows) { return nil, nil } return data, err } }) if err != nil { return nil, err } if d == nil { return nil, nil } return d.([]byte), nil } func (db *database) clearPersistentCache(pattern string) error { return db.clearPersistentCacheContext(context.Background(), pattern) } func (db *database) clearPersistentCacheContext(c context.Context, pattern string) error { _, err := db.ExecContext(c, "delete from persistent_cache where key like @pattern", sql.Named("pattern", pattern)) return err }