goutomroy

class Meta(type):
    """
    when
    class MyClass(metaclass=Meta):
        pass

    is encountered type's __call__ method is called and from that Meta's __prepare__, __new__, __init__
    is called one by one.
    """

goutomroy

class Author(models.Model):
    name = models.CharField(max_length=200)
    email = models.EmailField()

    def __str__(self):
        return self.name

    @property
    def url(self):
        return 'author/' + str(self.id)

goutomroy

import concurrent.futures
import urllib.request
from time import sleep

URLS = ['http://www.foxnews.com/',
        'http://www.cnn.com/',
        'http://europe.wsj.com/',
        'http://www.bbc.co.uk/',
        'http://some-made-up-domain.com/']

goutomroy

from multiprocessing import Pool

def f(x):
    return x*x

if __name__ == '__main__':
    p = Pool(5)
    print(p.map(f, [1, 2, 3]))

goutomroy

import time
import random
from multiprocessing import Process


class Processor(Process):
    def __init__(self, number):
        Process.__init__(self)
        self._number = number

goutomroy

import time
import random
from threading import Thread

class Worker(Thread):
    def __init__(self, number):
        Thread.__init__(self)
        self._number = number

    def run(self):

goutomroy

def check_balance(expression):
    open_list = ['(', '[', '{']
    close_list = [')', ']', '}']
    stack = []
    for c in expression:
        if c in open_list:
            stack.append(c)
        elif c in close_list:
            pos = close_list.index(c)
            if len(stack) > 0 and stack[-1] == open_list[pos]:

goutomroy

Reference:
Django/Postgres/Nginx/Gunicorn in Ubuntu: https://www.digitalocean.com/community/tutorials/how-to-set-up-django-with-postgres-nginx-and-gunicorn-on-ubuntu-16-04
Encryption: https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-16-04

Where you see "user", "myproject" and "myprojectuser" replace that with what is relevent to what you are working on.

User Setup

$ ssh root@SERVER_IP_ADDRESS
Complete login process

goutomroy

# Don't. Needs database hit
blog_id = Entry.objects.get(id=200).blog.id

# Do. The foreign key is already cached, so no database hit
blog_id = Entry.objects.get(id=200).blog_id

# Do. No database hit
blog_id = Entry.objects.select_related('blog').get(id=200).blog.id

goutomroy

class Author(models.Model):
    name = models.CharField(max_length=200)
    email = models.EmailField()

    def __str__(self):
        return self.name
 
class Blog(models.Model):
    name = models.CharField(max_length=100)
    tagline = models.TextField()