Storing a binary hash value in a Django model field

I have a twenty byte hex hash that I would like to store in a django model. If I use a text field, it's interpreted as unicode and it comes back garbled.

Currently I'm encoding it and decoding it, which really clutters up the code, because I have to be able to filter by it.

def get_changeset(self):
    return bin(self._changeset)

def set_changeset(self, value):
    self._changeset = hex(value)

changeset = property(get_changeset, set_changeset)

Here's an example for filtering

Change.objects.get(_changeset=hex(ctx.node()))

This is the approach that was recommended by a django developer, but I'm really struggling to come to terms with the fact that it's this ugly to just store twenty bytes.

Maybe I'm too much of a purist, but ideally I would be able to write

Change.objects.get(changeset=ctx.node())

The properties allow me to write:

change.changeset = ctx.node()

So that's as good as I can ask.

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1 Answer

If this issue is still of interest, Disqus' django-bitfield fits the bill:

https://github.com/disqus/django-bitfield

... the example code on GitHub is a little confusing at first w/r/t the modules' actual function, because of the asinine variable names -- generally I am hardly the sort of person with either the wherewithal or the high ground to take someone elses' goofy identifiers to task... but flaggy_foo?? Srsly, U guys.

If that project isn't to your taste, and you're on Postgres, you have a lot of excellent options as many people have written and released code for an assortment of Django fields that take advantage of Postgres' native type. Here's an hstore model field:

https://github.com/jordanm/django-hstore -- I have used this and it works well.

Here's a full-text search implementation that uses Postgres' termvector types:

https://github.com/aino/django-pgindex

And while I cannot vouch for this specific project, there are Django bytea fields as well:

https://github.com/aino/django-arrayfields

answered 2012-09-19T14:22:44.573

Storing a binary hash value in a Django model field

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