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

score 37 · Answer 1 · answered Mar 03 '14 at 20:42

37

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

answered Mar 03 '14 at 20:42

Sarah Messer

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score 35 · Accepted Answer · edited May 27 '15 at 02:58

35

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.

edited May 27 '15 at 02:58

Afriza N. Arief

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answered Feb 06 '11 at 19:12

Spacedman

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Thanks. I had been using something similar, but that snippet's far more simple. – Cerin Feb 07 '11 at 13:55
4

Thanks for the great snippet. Do you know if this supports filtering? i.e. Does `Foo.objects.filter(data=my_file)` process `my_file` through `get_data`? – Patrick Jan 03 '12 at 01:13

score 10 · Answer 3 · edited Apr 25 '12 at 08:49

10

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'

edited Apr 25 '12 at 08:49

Michael Waterfall

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answered Sep 22 '11 at 20:53

Anurag Uniyal

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Sorry for the lack of detail, I was investigating at that point. As of Django 1.2 the [db_type](https://docs.djangoproject.com/en/dev/howto/custom-model-fields/#django.db.models.Field.db_type) method takes a `connection` argument. This was the cause of the exception during `syncdb`. I have amended the code. – Michael Waterfall Apr 25 '12 at 08:50

B Robster · Answer 4 · 2012-07-10T23:30:35.587

0

Also, check out Django Storages' Database Storage:.

I haven't used it yet, but it looks awesome and I'm going to start using it as soon as I Post My Answer.

edited Jul 10 '12 at 23:30

answered Jul 10 '12 at 23:02

B Robster

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Django Blob Model Field

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