Comments on: Getting Started With MongoDB (Python)

By: Luke

Luke — Sun, 14 Feb 2010 00:58:03 +0000

I've noticed this issue with some of my Bottle projects before, but I'm not
exactly sure what's causing it – and it's been too intermittent for me to
reliably pin it down. I'll do some research and let you know if I find a
fix.

By: Andrew

Andrew — Sat, 13 Feb 2010 23:36:33 +0000

Strangely the redirect portion of /add-soldier/ doesn't work for me. In google chrome it directs
me to the link is broken page and firefox asks me if I want to resend POST data and then ends
up on an empty page. Not sure what I'm doing wrong.

By: Luke

Luke — Tue, 09 Feb 2010 21:04:05 +0000

Thanks for the heads-up, Mathias – I'll have to keep that in mind for
projects I write in the future.

By: Mathias Stearn

Mathias Stearn — Tue, 09 Feb 2010 20:54:00 +0000

If you are using 'ip' as the primary key to the users collection you may want to call it '_id'. Every object has an _id that is generated if you don't supply one. Also there is automatically a unique index on _id which will prevent you from creating two copies of the user.

By: Luke

Luke — Mon, 08 Feb 2010 20:26:34 +0000

Hi Mike,

Thanks for the heads-up – I knew about the upsert, but I didn't know
about the $push operation (or think to use it in my get_current_user
func). Thanks for the heads-up!

By: Mike Dirolf

Mike Dirolf — Mon, 08 Feb 2010 19:57:00 +0000

Great post! You might want to take a look at some of the other atomic update modifiers that MongoDB provides. For example, the add-soldier view could be written something like this:

def add_soldier():
current_user = get_current_user()
users.update(
{'ip': current_user['ip']},
{'$push': {
'army': random.choice(SOLDIER_NAMES),
}}
)
redirect('/')

Using $push will work even if the list doesn't exist to start with.

You could get even more advanced by doing an upsert, eliminating the need to check if the user exists in get_current_user - just grab the IP and do the update posted above (with upsert=True added as a kwarg). That will be just a single fire-and-forget operation for the entire request.

Anyway, already looks great as is - thanks for the post!