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https://github.com/samuelclay/NewsBlur.git
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80 lines
No EOL
2.6 KiB
Python
80 lines
No EOL
2.6 KiB
Python
from base64 import binascii
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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 django.db.models.signals import post_init
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from django.utils.encoding import smart_unicode
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from south.modelsinspector import add_introspection_rules
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add_introspection_rules([], ["^utils\.compressed_textfield\.StoryField"])
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add_introspection_rules([], ["^utils\.compressed_textfield\.CompressedTextField"])
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def uncompress_string(s):
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'''helper function to reverse django.utils.text.compress_string'''
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import cStringIO, gzip
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try:
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zbuf = cStringIO.StringIO(s)
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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:
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ret = s
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return ret
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class StoryField(models.TextField):
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__metaclass__ = models.SubfieldBase
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def to_python(self, value):
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if not value:
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return None
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# print 'From DB: %s %s' % (len(value), value[:25],)
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try:
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return unicode(value.decode('base64').decode('zlib'))
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except:
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return value
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def get_prep_save(self, value):
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if value:
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# print "Pre To DB: %s %s" % (len(value), value[:25])
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value = value.encode('zlib').encode('base64')
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# print "Post To DB: %s %s" % (len(value), value[:25])
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return super(StoryField, self).get_prep_save(value)
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class CompressedTextField(models.TextField):
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'''transparently compress data before hitting the db and uncompress after fetching'''
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def get_db_prep_save(self, value):
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if value is not None:
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value = compress_string(value)
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return models.TextField.get_db_prep_save(self, value)
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def _get_val_from_obj(self, obj):
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if obj:
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return uncompress_string(getattr(obj, self.attname))
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else:
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return self.get_default()
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def post_init(self, instance=None, **kwargs):
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value = self._get_val_from_obj(instance)
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if value:
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setattr(instance, self.attname, value)
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def contribute_to_class(self, cls, name):
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super(CompressedTextField, self).contribute_to_class(cls, name)
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post_init.connect(self.post_init, sender=cls)
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def get_internal_type(self):
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return "TextField"
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def db_type(self):
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from django.conf import settings
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db_types = {'mysql':'longblob','sqlite3':'blob'}
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try:
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return db_types[settings.DATABASE_ENGINE]
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except KeyError:
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raise Exception, '%s currently works only with: %s'%(self.__class__.__name__,','.join(db_types.keys())) |