getfriends_serial.go

func GetFriends(ctx context.Context, user int64) (map[string]*User, error) {
  // Produce
  var friendIds []int64
  for it := GetFriendIds(user); ; {
     if id, err := it.Next(ctx); err != nil {
        if err == io.EOF {
           break
        }
        return nil, fmt.Errorf("GetFriendIds %d: %w", user, err)
     } else {
        friendIds = append(friendIds, id)
     }
  }

  // Map
  ret := map[string]*User{}
  for _, friendId := range friendIds {
     if friend, err := GetUserProfile(ctx, friendId); err != nil {
        return nil, fmt.Errorf("GetUserProfile %d: %w", friendId, err)
     } else {
        ret[friend.Name] = friend
     }
  }
  return ret, nil
}