74 lines
2.0 KiB
Python
74 lines
2.0 KiB
Python
"""Models for the util app. """
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import gzip
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import logging
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from io import BytesIO
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from config_models.models import ConfigurationModel
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from django.db import models
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from django.utils.text import compress_string
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from opaque_keys.edx.django.models import CreatorMixin
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logger = logging.getLogger(__name__) # pylint: disable=invalid-name
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class RateLimitConfiguration(ConfigurationModel):
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"""
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Configuration flag to enable/disable rate limiting.
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Applies to Django Rest Framework views.
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This is useful for disabling rate limiting for performance tests.
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When enabled, it will disable rate limiting on any view decorated
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with the `can_disable_rate_limit` class decorator.
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.. no_pii:
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"""
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class Meta(ConfigurationModel.Meta):
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app_label = "util"
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def decompress_string(value):
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"""
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Helper function to reverse CompressedTextField.get_prep_value.
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"""
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try:
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val = value.encode('utf').decode('base64')
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zbuf = BytesIO(val)
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zfile = gzip.GzipFile(fileobj=zbuf)
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ret = zfile.read()
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zfile.close()
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except Exception as e: # lint-amnesty, pylint: disable=broad-except
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logger.error('String decompression failed. There may be corrupted data in the database: %s', e)
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ret = value
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return ret
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class CompressedTextField(CreatorMixin, models.TextField):
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"""
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TextField that transparently compresses data when saving to the database, and decompresses the data
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when retrieving it from the database.
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"""
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def get_prep_value(self, value):
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"""
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Compress the text data.
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"""
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if value is not None:
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if isinstance(value, str):
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value = value.encode('utf8')
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value = compress_string(value)
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value = value.encode('base64').decode('utf8')
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return value
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def to_python(self, value):
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"""
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Decompresses the value from the database.
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"""
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if isinstance(value, str):
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value = decompress_string(value)
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return value
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