Django Blob Model Field

Question

How do you store a "blob" of binary data using Django's ORM, with a PostgreSQL backend? Yes, I know Django frowns upon that sort of thing, and yes, I know they prefer you use the ImageField or FileField for that, but suffice it to say, that's impractical for my application.

I've tried hacking it by using a TextField, but I get occassional errors when my binary data doesn't strictly confirm to the models encoding type, which is unicode by default. e.g.

psycopg2.DataError: invalid byte sequence for encoding "UTF8": 0xe22665

Solution 1

This snippet any good:

http://djangosnippets.org/snippets/1597/

This is possibly the simplest solution for storing binary data in a TextField.

import base64

from django.db import models

class Foo(models.Model):

    _data = models.TextField(
            db_column='data',
            blank=True)

    def set_data(self, data):
        self._data = base64.encodestring(data)

    def get_data(self):
        return base64.decodestring(self._data)

    data = property(get_data, set_data)

There's a couple of other snippets there that might help.

Solution 2

If you're using Django >= 1.6, there's a BinaryField

Solution 3

I have been using this simple field for 'mysql' backend, you can modify it for other backends

class BlobField(models.Field):
    description = "Blob"
    def db_type(self, connection):
        return 'blob'