public override async Task <ScreamResult> RemoveAsync(int screamId)
{
if (!Scream.IsValidId(screamId))
{
throw new NullReferenceException("invalid scream Id");
}
var scream = await DB.Screams.AsNoTracking().Where(s => s.Id == screamId).SingleOrDefaultAsync();
var comments = await DB.Comments.AsNoTracking().Where(c => c.ScreamId == screamId).ToListAsync();
DB.Comments.RemoveRange(comments);
if (scream == null)
{
throw new NullReferenceException("scream not exist");
}
DB.Screams.Remove(scream);
int effects = await DB.SaveChangesAsync();
if (effects == comments.Count + 1)
{
await _redis.KeyDeleteAsync(Scream.GetCacheKey(screamId));
return(QuickResult.Successful());
}
return(QuickResult.Unsuccessful("Delete scream fail"));
}
/// <summary>
/// get the subject of scream
/// </summary>
/// <param name="screamId"></param>
/// <returns></returns>
public override async Task <Scream> GetScreamAsync(int screamId)
{
if (!Scream.IsValidId(screamId))
{
return(null);
}
string redisValue;
string currentKey = Scream.GetCacheKey(screamId);
Scream result = null;
if (await _redis.KeyExistsAsync(currentKey))
{
redisValue = await _redis.StringGetAsync(currentKey);
result = new Scream(
JsonConvert.DeserializeObject <ScreamBackend.DB.Tables.Scream>(redisValue),
this
);
}
else
{
var model = await DB.Screams.AsNoTracking().SingleOrDefaultAsync(s => s.Id == screamId);
if (model == null)
{
return(null);
}
result = new Scream(model, this);
redisValue = JsonConvert.SerializeObject(result.Model);
await _redis.StringSetAsync(key : currentKey, redisValue);
}
await _redis.KeyExpireAsync(currentKey, TimeSpan.FromHours(1));
return(result);
}