- Author:
- bwhittington
- Posted:
- May 7, 2009
- Language:
- Python
- Version:
- 1.0
- Score:
- 0 (after 0 ratings)
This snippet updates http://www.djangosnippets.org/snippets/383/ for Django 1.0+, and adds support for sqlite3. Original snippet text: A CompressedTextField to transparently save data gzipped in the database and uncompress at retrieval.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | from django.db import models
from django.utils.text import compress_string
from django.db.models.signals import post_init
def uncompress_string(s):
'''helper function to reverse django.utils.text.compress_string'''
import cStringIO, gzip
try:
zbuf = cStringIO.StringIO(s)
zfile = gzip.GzipFile(fileobj=zbuf)
ret = zfile.read()
zfile.close()
except:
ret = s
return ret
class CompressedTextField(models.TextField):
'''transparently compress data before hitting the db and uncompress after fetching'''
def get_db_prep_save(self, value):
if value is not None:
value = compress_string(value)
return models.TextField.get_db_prep_save(self, value)
def _get_val_from_obj(self, obj):
if obj:
return uncompress_string(getattr(obj, self.attname))
else:
return self.get_default()
def post_init(self, instance=None, **kwargs):
value = self._get_val_from_obj(instance)
if value:
setattr(instance, self.attname, value)
def contribute_to_class(self, cls, name):
super(CompressedTextField, self).contribute_to_class(cls, name)
post_init.connect(self.post_init, sender=cls)
def get_internal_type(self):
return "TextField"
def db_type(self):
from django.conf import settings
db_types = {'mysql':'longblob','sqlite3':'blob'}
try:
return db_types[settings.DATABASE_ENGINE]
except KeyError:
raise Exception, '%s currently works only with: %s'%(self.__class__.__name__,','.join(db_types.keys()))
|
More like this
- Template tag - list punctuation for a list of items by shapiromatron 9 months, 4 weeks ago
- JSONRequestMiddleware adds a .json() method to your HttpRequests by cdcarter 10 months ago
- Serializer factory with Django Rest Framework by julio 1 year, 4 months ago
- Image compression before saving the new model / work with JPG, PNG by Schleidens 1 year, 5 months ago
- Help text hyperlinks by sa2812 1 year, 6 months ago
Comments
Works great!
Small hack for Django 1.3 (old DATABASE_ settings are gone) --
#
Another tweak, to transparently support unicode/utf8 data (zlib.crc32 needs plain binary) --
#
Please login first before commenting.