Django prefetch_related VS select_related in a single database query

Imagine the following model:

class Parent(Model):
    ...

class Child(Model)
    parent = ForeignKey(Parent)
    ...

I want to list all parents along with first related child.

Cracking wifi password with pyrit and NVIDIA GPU on Amazon AWS

WPA algorithm is very secure, and to get the password usually we have only one way - to brute force it, which could take huge time if password is strong enough. But what if instead of using regular CPUs we would use a power of GPU? Amazon says, that we can use up to 1,536 CUDA cores on g2.2xlarge instance, which costs $0.65 per Hour. Sounds very promising, so let's see how it can help us to speed up password brute force.

Below I will give step-by-step tutorial on how to deploy Amazon GPU instance and run pyrit (python tool) to crack password using GPU.

Tricky questions: function parameters with default mutable values

Today I discovered one confusing feature of Python. And also decided to open new category on my blog, which will be called "tricky python questions".

def append(num, to=[]):
    to.append(num)
    return to

aa = append(1)
print aa

bb = append(2)
print bb

Using Python passlib in Java applications

Some of my readers might ask why would python developer need to do something in java? I've never thought I would need to code in java too. But if you saw my last post, I was talking about how to implement SSO with django website. And one of its main components is java based application, which I wanted to customize.

So here is the problem: I needed to verify password hashes in java application (java 7), but those hashes were generated with python passlib library (pbkdf2_sha512). First I even tried to implement password verification in java, but then I gave up and decided to do it easy way.

How to setup Shibboleth Identity Provider 3 with Django Website

Recently I was given a task to setup Shibboleth SSO to integrate different python websites with single sign on. There is official shibboleth documentation, but it's quite difficult to understand, especially for beginners. After spending days of googling and reading different forums, I decided to create step-by-step guide for beginners on how to install Shibboleth SSO with django website.

Web scraping using socks/http proxies

While extracting data from websites most probably you will notice some kind of access limiting for a single IP address. In that case it is good to use proxies. In my scraping projects I've been using both http and socks proxies.

Using django models in standalone application

One of my favorite things about Django is its loosely coupled design. It means that you can use each part independently and not affect others. And one of the parts that I often use in my applications is Djagno Models.

There is nothing difficult to use django models in standalone application. You just need to start new django project and then remove all unnecessary stuff leaving only models. Below I will show it on example.