public void StoreAnswer(Answer answer)
{
using var redis = RedisManager.GetClient();
if (answer.Id == default(long))
{
answer.Id = redis.As <Answer>().GetNextSequence();
answer.CreatedDate = DateTime.UtcNow;
}
//Store as a 'Related Answer' to the parent Question
redis.As <Question>().StoreRelatedEntities(answer.QuestionId, answer);
//Populate user => answer index
redis.AddItemToSet(UserAnswerIndex.Answers(answer.UserId), answer.Id.ToString());
}
public void VoteAnswerDown(long userId, long answerId)
{
//Populate Question => User and User => Question set indexes in a single transaction
RedisManager.ExecTrans(trans =>
{
//Register downvote against answer and remove any upvotes if any
trans.QueueCommand(redis => redis.AddItemToSet(AnswerUserIndex.DownVotes(answerId), userId.ToString()));
trans.QueueCommand(redis => redis.RemoveItemFromSet(AnswerUserIndex.UpVotes(answerId), userId.ToString()));
//Register downvote against user and remove any upvotes if any
trans.QueueCommand(redis => redis.AddItemToSet(UserAnswerIndex.DownVotes(userId), answerId.ToString()));
trans.QueueCommand(redis => redis.RemoveItemFromSet(UserAnswerIndex.UpVotes(userId), answerId.ToString()));
});
}
/// <summary>
/// Delete Answer by performing compensating actions to StoreAnswer() to keep the datastore in a consistent state
/// </summary>
/// <param name="questionId"></param>
/// <param name="answerId"></param>
public void DeleteAnswer(long questionId, long answerId)
{
using var redis = RedisManager.GetClient();
var answer = redis.As <Question>().GetRelatedEntities <Answer>(questionId).FirstOrDefault(x => x.Id == answerId);
if (answer == null)
{
return;
}
redis.As <Question>().DeleteRelatedEntity <Answer>(questionId, answerId);
//remove user => answer index
redis.RemoveItemFromSet(UserAnswerIndex.Answers(answer.UserId), answerId.ToString());
}
