we will discuss these Topic

Object realtion mapper

URLs Views

Template

Forms

Authentication

Admin

Internationalization

Security

Extra Deatils are

Model

View

Controller

Database

Session

Cookies

Ajax

Services

start app

django-admin startproject nameOfProject

Run Server

Python manage.py runserver

Run server on local machine

we can modal data entierly in Python and we get rich Database API for free we can write SQL if needed

we can modal dataentierly in Python and we get rich Database API for free we can write SQL if needed

we can modal dataentierly in Python and we get rich Database API for free we can write SQL if needed

A clean URL schema is important for app Django Provids a god way

we define schime or URLs in URL config where we simply map out all the app where your will be re-dirted etc

It is simaply the HTML Pages

use for front end develpor and is flexible we can also use the Python logic in the template

Same as simple HTML

A poweful way the we can render the HTML and appply the Logic in Python

Mostaly used in Input fields to handel data user can creat and upload data

import forms

It comes along with the authenications and sessions and permissons to the user

make easy for user that can Login and og out in the app

we can secure pages also

from django.contrib.auth.decorators import login_required

It provide automatic and production ready admin Panel

Admin can easily manage the content of the site

Provides many Hooks for the customization

from django.contrib import admin

It provide us the method that we can change the language on the base of time zone

It is up to developers that what part of app should be translates in what time zone

from django.utils.translation import gettext

It provids a lot of security featues like

SQL injection

Remote code Execution

Cross SIte Request Forgery

Cross site script

Clickjacking

Additional fetaurs

setting.py : is used for the project setting of Projexct

urls : include all URLs of the app and Links on click of functions

we can create appp in side Django Projects

Like Big app having a large services and featurs as in App

Command is : " python manage.py startapp nameofApp" it will creat another folder in that

provide ready to use UI for Admin Panel

Make sure You have install all depencies foe admin panel check out at setting .py file

we need to initize the Database

python manage.py mirgant creatsuperuser

Then we need to add it to URLs file url(r'^admin/', include(admin.site.urls)),

simply they are Python functions that take request and response to the request

Response can be simply the HTML file or Documnet or Image

we can also render HTML pages in the response

def hello(request):
return render(request, "myapp/template/hello.html", {})

It is Made up of follwing three Patterns

Model : Lowest form that is responsible for mantaining the data

View : is response for Displaying the data

Controller : software that interact between Model and view

it is responsible for the managimg the Data of the application

It response to the request from the view

it is also responsible to instructions from controller to update itself

it Means Presenting data In particular form by controller decision to present data

They are script base template for the PHP ASP and very easy to inregrate with AJAX technolgy

It is responsible for responde the user input and and perform interaction on data model view

It recive input then validate data and perform Bussiness operations on it

It is used for mapping and is done in URL.py file. When a request is made in a App it look in URL .py file if it is present then it will renser the file other wise 404 page

from django.conf.urls import patterns, include, url

It provides us the way that we can write and cal pythin code in the HTML file and use then seprately It take three argumnets

Render functions : This function take three argumnets

Request : The inital request

Path to the Template : This is path relative to the TEMOPLATE options in the project setting.py

Dictory of parameters : a dictory that contain all varibles needed for template

Model is a class that represent the table and colletion in Data Base they are define in model.py file

After creating Model type $python manage.py syncdb

we can easily manuplate the data in Models

we can re-direct the user as we want because of certin resions or errors

redirct method take as a argumnet you want to redirect as a string

from django.shortcuts import render, redirect

It come along pre- install with SMTP package hostname, server name password contetct etc

from django.core.mail import send_mail

we can also attch details to the email and we can send one email to multiple peoples

In some case writting view as have seen earily is reallly heavy It offer a simple view that is called a generic view

It offers a set of classes not functions classes that inherit one another

import django.views.generic there are 10 views

It comes along with packeges and is vry easy to use them

from django import forms

we have to define all logic in the class() we need to define inherit Django classes with form attribute

It is useful for Uploading files

Make sure you have install PIL library in Django

It take the Data and verify befor we upload on the server

as far we have this Python server But it is only foe testing and development purpose in real world seniro we will use server like Apache and Ngnix

wsgi.py is the file that we link with the Django and Server

we will have to define the pathe in the file and detils

we want to store data for the client side or visitors data as per request

Sessions

from client side we wnat to store useful data on web server

Have sessions foe Cookies and client side cookies have session ID for identifications

'django.contrib.sessions.middleware. SessionMiddleware'

information is store on Database and then

Means we want result of something as a calculation that we don,t perform

Django comes along with the catching system For used in Dynamic frameworks

Caching is done in Database and or file system and is done in Setting,py file

python manage.py createcachetable

we can catch the entire site and we can also cache a page as we want

The comments framework makes it easy to attach comments to any model in your app.

then edit the setting.py file

python manage.py syncdb

It is used to reduce the number of pages load Mostaly used for best user experience

we need to download the dajax library with witch we can develop easily and quickly in Loic in app in Javavscript

$ pip install django_dajax

It comes along with the RSS by django.contrib.syndication.views.Feed class

we can creat a latest field of comments done on the app define logic in feed.py and we can put feed where we want

session is a way with witch we can remember who is the user and what he have done in the app

Store session data on the server we have to import them to use

we can use differt models as we want in app Mostaly use SQL and store data

MySql and PostgrSql are more heavy types of data base SQLlite is liter form we can store data in a file

we can define the Queries in the Python classes

It support Text Numbers , Integer, Blogs bianay data audio or images , Reals Numbers

MYSQL

It support much more than sql char,varachar, smallint, int ,Bigint,Floats, Double, large Nmbers

we have to creat database as Table

we have to creat a table first and define all things in it as Class and Name

we have to define the Name and data types in the class

Auto Increment allows us to update the data as we enter the Data

Constarins : Not Null , Check,Default and more also Data also need to be valid

it is used to insert the data to the class Or Object we have defined

Data will be enter behind the scen in the Object defined

It is used to select the Data fom The database and show in the UI or something else

data is store in form of row and coloums

SELECT * FROM flight: it will select all colums from a Object

There are certin limitaion of a server it can handel limited nubers of requests

So we use vaertical and Horizonatl scalling Mostaly use Horizonatl Scalling

Load Balancer is a haradware that diverge the Number of request to different server of app

A app can have 10 or more server for the app

Random choice send request randomaly

Round Robine : First Requesrt is send to the first server and second is to the second similRY

If a user is login in to App aand is redirected to sercer One Next time if he is logged into another server and willnot be authenticated with session

so to identify the user we have ssveral methods

It will look if a user is loogin in to 1 server will be diverted to One server and Knows him and store information on server

All sereves have access to data nase and Data is store in the Data base

So all data is store in Datbase and server find out if a user is login and what are other Information of a user and reconize a person

When A PERSON VISIT A SITE is Issused a Cookies ansd that hold information of a user

On each request cookies are also send to the server to identify user

having many server alike if a server failed out what will happen

Load balancer will send a Ping to server if response is not getting back then it wil know a servicer is Fails and will not send request of user to that server

in a app server Databases are running on Onther servers and they have acces to then

They also have limitaion so we have Partition on the databases and different parts of app can handel difernet form of Databases

If Database server fail noNe of our App is going to work so we have

Single-Primary Replication : Only One main function can write and update data and others can only read data If there are to many user comming and updating data It might Often Fail

Multi-Primary Replication : Threr are multiple ways we van read and write a Database But all Databases nedd to be Synchonrixe update all at same time

Mostaly Multi-Primary is useef they often have some issues It a user deleta a data and One user Updata same Data at the same time them what will happen we have to define all details

suppose we have a front pages of a App and page get data from Database and show result on each request

If number of request Increase then alot of load comes on the pages and app It make it solw

we can define it as Storing save version of Data that we can access it more quickly so we don,t need to make Number of requet to our data base

One way is to do is On the Browser Side we can ask the client Browser to save the copy of the Page so next time user make request local it from the LOcaly not from the Database

Browser often do it because don,t make reqeuest and load data from the local storage

It make a process faster and good to server don,t make load on server

Cache-Control : maz-age=8600 when this time in seconds pass it make new version of page

we can also persform server side Catchiog

we have multiple servers and these servers are communicating with each other and Database and Cache

There we store information that we don,t want to load rather to again recalculate

Djando also have a caching framework Pre-view catching

So how we can say that our web app is scaleable and secure we have to look each and every aspect of it and lowlevel details of it