// GET: sessions/teacher
public ActionResult Teacher()
{
if (!this.GetUserIsTeacher())
{
return(Redirect(Url.Action("Logout", "Account", null, "https")));
}
HostingEnvironment.QueueBackgroundWorkItem(ct => ItalkiHelper.EnsureIsReady());
return(View());
}
public async Task <IHttpActionResult> PostBooking([FromBody] JObject json)
{
TimeUtils.ThrowIfClientTimeIsAmbiguous((string)json["localTime"], (int)json["localTimezoneOffset"]);
var teacherUserId = (int)json["teacherUserId"];
var start = (DateTime)json["start"];
var end = (DateTime)json["end"];
var price = (decimal)json["price"];
var userId = this.GetUserId();
var teacher = SessionHelper.ItalkiTeachers.First(i => i.UserId == teacherUserId);
var periods = await SessionHelper.GetTeacherPeriods(teacherUserId, true);
var available = periods.Any(i => (i.Start <= start) && (i.End >= end));
if (!available)
{
throw new Exception(ItalkiHelper.TimeSlotUnavailableError);
}
/* Compensation is the mechanism by which previously completed work can be undone or compensated when a subsequent failure occurs.
* The Compensation pattern is required in error situations when multiple atomic operations cannot be linked with classic transactions.
*/
// We cannot use a transaction in a heterogeneous storage mediums. An orphaned message on Azure Table is not a problem, we do not compensate it on error. The main message metadata is in the database anyway.
var message = (string)json["message"];
var messageExtId = await SessionHelper.SaveMessageAndGetExtId(message);
var sessionId = (await DapperHelper.QueryResilientlyAsync <int>("dbo.sesBookSession", new
{
UserId = userId, // who requests and pays
Start = start,
End = end,
TeacherUserId = teacherUserId,
Price = price,
MessageExtId = messageExtId,
},
CommandType.StoredProcedure))
.Single();
// We will write to the log.
var partitionKey = KeyUtils.GetCurrentTimeKey();
// Book the session on Italki.
try
{
long?sessionExtId = null;
#if DEBUG
sessionExtId = 0;
#else
var helper = new ItalkiHelper();
sessionExtId = await helper.BookSession(teacher.CourseId, start, teacher.ScheduleUrl, partitionKey);
#endif
if (sessionExtId.HasValue)
{
await DapperHelper.ExecuteResilientlyAsync("dbo.sesUpdateSessionExtId", new
{
SessionId = sessionId,
ExtId = sessionExtId,
},
CommandType.StoredProcedure);
}
}
catch (Exception ex)
{
// Compensation on booking failure.
// Clean up the session.
DapperHelper.ExecuteResiliently("dbo.sesCancelSession", new
{
UserId = userId,
SessionId = sessionId,
ClearUsers = true,
},
CommandType.StoredProcedure);
throw new UserAlertException("Failed to book session", ex);
}
HostingEnvironment.QueueBackgroundWorkItem(async(ct) => await SendSmsMessage("Session request. Teacher " + teacherUserId.ToString(), partitionKey));
return(StatusCode(HttpStatusCode.NoContent));
}
// GET: sessions/
public ActionResult Index()
{
HostingEnvironment.QueueBackgroundWorkItem(ct => ItalkiHelper.EnsureIsReady());
return(View());
}
