private List <QuestionResult> ToQuestionResults(IEnumerable <Question> questions)
{
var uniqueUserIds = questions.Map(x => x.UserId).ToHashSet();
var usersMap = GetUsersByIds(uniqueUserIds).ToDictionary(x => x.Id);
var results = questions.Map(x => new QuestionResult {
Question = x
});
var resultsMap = results.ToDictionary(q => q.Question.Id);
results.ForEach(x => x.User = usersMap[x.Question.UserId]);
//Batch multiple operations in a single pipelined transaction (i.e. for a single network request/response)
RedisManager.ExecTrans(trans =>
{
foreach (var question in questions)
{
var q = question;
trans.QueueCommand(r => r.GetSetCount(QuestionUserIndex.UpVotes(q.Id)),
voteUpCount => resultsMap[q.Id].VotesUpCount = voteUpCount);
trans.QueueCommand(r => r.GetSetCount(QuestionUserIndex.DownVotes(q.Id)),
voteDownCount => resultsMap[q.Id].VotesDownCount = voteDownCount);
trans.QueueCommand(r => r.As <Question>().GetRelatedEntitiesCount <Answer>(q.Id),
answersCount => resultsMap[q.Id].AnswersCount = answersCount);
}
});
return(results);
}
public QuestionStat GetQuestionStats(long questionId)
{
using var redis = RedisManager.GetReadOnlyClient();
var result = new QuestionStat
{
VotesUpCount = redis.GetSetCount(QuestionUserIndex.UpVotes(questionId)),
VotesDownCount = redis.GetSetCount(QuestionUserIndex.DownVotes(questionId))
};
result.VotesTotal = result.VotesUpCount - result.VotesDownCount;
return(result);
}
public void VoteQuestionDown(long userId, long questionId)
{
//Populate Question => User and User => Question set indexes in a single transaction
RedisManager.ExecTrans(trans =>
{
//Register downvote against question and remove any upvotes if any
trans.QueueCommand(redis => redis.AddItemToSet(QuestionUserIndex.DownVotes(questionId), userId.ToString()));
trans.QueueCommand(redis => redis.RemoveItemFromSet(QuestionUserIndex.UpVotes(questionId), userId.ToString()));
//Register downvote against user and remove any upvotes if any
trans.QueueCommand(redis => redis.AddItemToSet(UserQuestionIndex.DownVotes(userId), questionId.ToString()));
trans.QueueCommand(redis => redis.RemoveItemFromSet(UserQuestionIndex.UpVotes(userId), questionId.ToString()));
});
}