// WithIDInClass returns the Student with a specific ID in a single class, if one exists.
func WithIDInClass(c appengine.Context, id string, class *classes.Class, asOf time.Time) (*Student, error) {
key := datastore.NewKey(c, "Student", id, 0, class.Key(c))
student := &Student{}
switch err := datastore.Get(c, key, student); err {
case nil:
if student.DropIn && student.Date.Before(asOf) {
return nil, ErrStudentNotFound
}
student.ID = key.StringID()
return student, nil
case datastore.ErrNoSuchEntity:
return nil, ErrStudentNotFound
default:
return nil, err
}
}
// In returns a list of all Students registered for a class. The list
// will include only those drop-in Students whose date is not in the
// past.
func In(c appengine.Context, class *classes.Class, now time.Time) []*Student {
q := datastore.NewQuery("Student").
Ancestor(class.Key(c))
students := []*Student{}
_, err := q.GetAll(c, &students)
if err != nil {
c.Errorf("Failed to look up students for %d: %s", class.ID, err)
return nil
}
filtered := []*Student{}
for _, student := range students {
if student.DropIn && student.Date.Before(now) {
continue
}
filtered = append(filtered, student)
}
return filtered
}