Tornado: non-blocking web server

Tornado is an non-blocking, scalable web server. It can handle thousands of simultaneous standing connections, which means it is ideal for real-time web services

Install:
Download package from http://www.tornadoweb.org/ and install from python.

With tornado you will get many demo projects for helloworld, appengine, auth, blog, chat, facebook, s3server so on.

django hello world

Django is python high level framework. It always encourage rapid development and clean, pragmatic design. It lets you build high-performing, elegant web applications quickly. You can also develop back-end API(django have some cool library for it). Lets go....

Create a django project.

From command prompt:
Create django project: django-admin.py startproject django_hello_world
Create django app: python manage.py startapp hello

I am using pycharm, so I can create my project from pycharm.

Here I show you only which file I need to edit for run hello world project.
You can download full projcet from here

 

// settings.py

# set admin
ADMINS = (
    ('jony', 'jony.cse@gmail.com'),
)

#set database
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3', 
        # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'.
        'NAME': 'dev.db',                      
        # Or path to database file if using sqlite3.
        'USER': '',                      # Not used with sqlite3.
        'PASSWORD': '',                  # Not used with sqlite3.
        'HOST': '',                      
         # Set to empty string for localhost. Not used with sqlite3.
        'PORT': '',                      
        # Set to empty string for default. Not used with sqlite3.
    }
}
INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    # Uncomment the next line to enable the admin:
    # 'django.contrib.admin',
    # Uncomment the next line to enable admin documentation:
    # 'django.contrib.admindocs',
    'hello', # need to install your app
)

//views.py

# create a view function which we will call
from django.http import HttpResponse
def hello_view(request):
    return HttpResponse("Hello my django!!")
	
//url.py

#call view from url
from hello import views
urlpatterns = patterns('',
    url(r'^hello_django/$', views.hello_view, name='my_hello_view'),
)

running project:

commands:
python manage.py syncbd 
# when you make chage on db, need to run this command
# create super user
python manage.py runserver 8080

Not hit this url:
http://127.0.0.1:8080/hello_django/

django install

Install from pip:
pip install Django

or
download django package and install by command python manage.py install

Beautiful Soup CSS selector

Beautiful Soup supports a subset of the CSS selector standard. Just construct the selector as a string and pass it into the .select() method of a Tag or the BeautifulSoup object itself.
I used this html file for practice. All source code available on github

 
from pprint import pprint
from bs4 import BeautifulSoup

html_content = open('bs_sample3.html') 
# http://dl.dropbox.com/u/49962071/blog/python/resource/bs_sample3.html
soup = BeautifulSoup(html_content) # making soap

pprint(soup.select("title")) # get title tag
pprint(soup.select("body a")) # all a tag inside body
pprint(soup.select("html head title")) # html->head->title
pprint(soup.select("head > title")) # head->title
pprint(soup.select("p > a")) # all a tag that inside p
pprint(soup.select("body > a")) # all a tag inside body
pprint(soup.select(".sister")) # select by class
pprint(soup.select("#link1")) # select by id
pprint(soup.select('a[href="http://example.com/elsie"]')) 
# find tags by attribute value
pprint(soup.select('a[href^="http://example.com/"]'))
# find tags by attribute value, all contains 'http://example.com/'
pprint(soup.select('p[lang|=en]')) # Match language codes

Beautiful Soup find_all() search API

find_all() is the most popular method in the Beautiful Soup search API. It's reduce your code size massively. We can use regular expression, custom function into it. I used this html file for practice.
All source code available on github

 
from pprint import pprint
import re
from bs4 import BeautifulSoup

html_content = open('bs_sample.html') 
#http://dl.dropbox.com/u/49962071/blog/python/resource/bs_sample.html
soup = BeautifulSoup(html_content) # making soap

for tag in soup.find_all(re.compile("^p")): # find all tag start with p
    print tag.name

for tag in soup.find_all(re.compile("t")): # find all tag contains t
    print tag.name

for tag in soup.find_all(True): # find all tag
    print tag.name

pprint(soup.find_all('a')) # find all a tag
print 20*"++"
pprint(soup.find_all(["a", "b"])) # find multiple tag


def has_class_but_no_id(tag):
    return tag.has_key('class') and not tag.has_key('id')

pprint(soup.find_all(has_class_but_no_id)) 
# pass a function to find_all

pprint(soup.find_all(text=re.compile("sisters"))) 
# find all tag content contains key 'sisters'
print 20*"++"
pprint(soup.find_all(href=re.compile("my_url"))) # all links contains key "my_url"
pprint(soup.find_all(id=True)) # all links has id
pprint(soup.find_all(class_=True)) # all links has class

def has_six_characters(css_class):
    return css_class is not None and len(css_class) == 7

pprint(soup.find_all(class_=has_six_characters)) 
# find all class name contains 7 characters

pprint(soup.find_all("a", "sister")) # find all a tag have class named 'sister'
pprint(soup.find_all("a", re.compile("sister"))) 
# find all a tag have class named contains 'sister'
print 20*"++"

pprint(soup.find_all(href=re.compile("elsie"), id='link1'))
# url name contains elsie and have id = link1
pprint(soup.find_all(attrs={'href' : re.compile("elsie"), 'id': 'link1'})) 
# url name contains elsie and have id = link1

pprint(soup.find_all("a", limit=2)) # use limit on find_all

pprint(soup.html.find_all("title", recursive=True)) # use recursive on findall

explore git

My git notes. I practiced git on github.

 
Git is awesome. I am using git many of my projects. Git has many usefull commands, for me
it is hard to remember all commands. So I make my own git notes, you can make yours.

Beautiful Soup 4 exploring

Quick explore to Beautiful Soup 4. I used this document for practicing.
All source codes of this blog available on github.

 
from pprint import pprint
from bs4 import BeautifulSoup

html_content = open('bs_sample.html') 
# http://dl.dropbox.com/u/49962071/blog/python/resource/bs_sample.html

soup = BeautifulSoup(html_content) # making soap

print soup.prettify() # prettify html_content even complete uncompleted tag

print soup.title # page title tag
print soup.title.name # page title name
print soup.title.parent.name # page title parent
print soup.p # first p tag
print soup.p.string # string content of first p tag
print soup.p['class'] # first p tag class name
print soup.a  # first a tag
pprint( soup.find_all('a'))  # all a tag
pprint( soup.find_all('p'))  # all p tag
print soup.find(id='link3') # find tag with id = link3
print 'All links:'
for link in soup.find_all('a'):
    print link.get('href') # get url

print soup.get_text() # return text part of html_document