public async Task ProcessAsync(MessageContext context, HttpApiClient api)
{
_newbieContext.RemoveRange(_newbieContext.Recommendations);
await _newbieContext.SaveChangesAsync().ConfigureAwait(false);
await api.SendMessageAsync(context.Endpoint, "清除完成。");
}
/// <summary>
/// Query user play records.
/// Parameters must have same number of elements,
/// and there must not be any duplicate <c>userId</c> and <c>mode</c> combination.
/// </summary>
/// <param name="context">Database context to use.</param>
/// <param name="userIds">List of queried user ids. <c>userIds</c>, <c>modes</c> and <c>startIndecies</c> must have same number of elements.</param>
/// <param name="modes">List of queried modes. <c>userIds</c>, <c>modes</c> and <c>startIndecies</c> must have same number of elements.</param>
/// <param name="startIndecies">List of first numbers played. <c>userIds</c>, <c>modes</c> and <c>startIndecies</c> must have same number of elements.</param>
/// <returns>A list of user play records.</returns>
public static async Task <IList <UserPlayRecord> > GetUserPlayRecordsAsync(
NewbieContext context,
IEnumerable <int> userIds,
IEnumerable <Mode> modes,
IEnumerable <int> startIndecies)
{
var tracking = context.ChangeTracker.QueryTrackingBehavior;
context.ChangeTracker.QueryTrackingBehavior = QueryTrackingBehavior.NoTracking;
// TODO: Verify that there is no repeating conditions (with same userId and mode).
// If so, select the minimum of StartNumber.
var filters = userIds.Zip(modes).Zip(startIndecies, (tuple, start) =>
{
var(userId, mode) = tuple;
return(new PlayRecordQueryTemp
{
UserId = userId,
Mode = mode,
StartNumber = start,
});
});
var result = await context.Database.CreateExecutionStrategy().ExecuteAsync(async() =>
{
using (await context.Database.BeginTransactionAsync(IsolationLevel.ReadCommitted).ConfigureAwait(false))
{
await context.PlayRecordQueryTemps.AddRangeAsync(filters).ConfigureAwait(false);
await context.SaveChangesAsync().ConfigureAwait(false);
return(await(from r in context.UserPlayRecords
join f in context.PlayRecordQueryTemps on new { r.UserId, r.Mode } equals new { f.UserId, f.Mode }
where r.PlayNumber >= f.StartNumber
select r).ToListAsync().ConfigureAwait(false));
}
}).ConfigureAwait(false);
context.ChangeTracker.QueryTrackingBehavior = tracking;
return(result);
}