84 lines
3.1 KiB
Python
84 lines
3.1 KiB
Python
"""
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WE'RE USING MIGRATIONS!
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If you make changes to this model, be sure to create an appropriate migration
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file and check it in at the same time as your model changes. To do that,
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1. Go to the mitx dir
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2. ./manage.py schemamigration courseware --auto description_of_your_change
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3. Add the migration file created in mitx/courseware/migrations/
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ASSUMPTIONS: modules have unique IDs, even across different module_types
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"""
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from django.db import models
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from django.core.cache import cache
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from django.contrib.auth.models import User
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from cache_toolbox import cache_model, cache_relation
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CACHE_TIMEOUT = 60 * 60 * 4 # Set the cache timeout to be four hours
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class StudentModule(models.Model):
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# For a homework problem, contains a JSON
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# object consisting of state
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MODULE_TYPES = (('problem','problem'),
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('video','video'),
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('html','html'),
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)
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## These three are the key for the object
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module_type = models.CharField(max_length=32, choices=MODULE_TYPES, default='problem', db_index=True)
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module_id = models.CharField(max_length=255, db_index=True) # Filename for homeworks, etc.
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student = models.ForeignKey(User, db_index=True)
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class Meta:
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unique_together = (('student', 'module_id'),)
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## Internal state of the object
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state = models.TextField(null=True, blank=True)
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## Grade, and are we done?
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grade = models.FloatField(null=True, blank=True, db_index=True)
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max_grade = models.FloatField(null=True, blank=True)
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DONE_TYPES = (('na','NOT_APPLICABLE'),
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('f','FINISHED'),
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('i','INCOMPLETE'),
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)
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done = models.CharField(max_length=8, choices=DONE_TYPES, default='na', db_index=True)
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# DONE_TYPES = (('done','DONE'), # Finished
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# ('incomplete','NOTDONE'), # Not finished
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# ('na','NA')) # Not applicable (e.g. vertical)
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# done = models.CharField(max_length=16, choices=DONE_TYPES)
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created = models.DateTimeField(auto_now_add=True, db_index=True)
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modified = models.DateTimeField(auto_now=True, db_index=True)
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def __unicode__(self):
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return self.module_type+'/'+self.student.username+"/"+self.module_id+'/'+str(self.state)[:20]
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@classmethod
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def get_from_cache(cls, student, module_ids):
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k = cls.key_for(student, module_ids)
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student_modules = k.get(k)
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if student_modules is None:
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student_modules = StudentModule.objects.filter(student=student, module_id__in=module_ids)
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# It's possible it really doesn't exist...
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if student_modules is not None:
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k.set(k, student_modules, CACHE_TIMEOUT)
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return student_modules
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@classmethod
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def clear_cache_for(cls, student, module_ids):
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k = cls.key_for(student_id, module_ids)
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cache.delete(k)
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@classmethod
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def key_for(cls, student, module_ids):
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module_ids_hash = md5(",".join(sorted(modules_ids))).hexdigest()
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return "StudentModule-student_id:{0};module_ids_hash:{1}".format(student.id, module_ids_hash)
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cache_model(StudentModule) |