developing software as a service app with python & django

Developing Software As A Service with Python & DjangoAllan Spartacus Mangune, CPA, MsCIS

Friday, January 18, 13

Allan Spartacus ManguneCertified Public Accountant

MSCIS - University of Phoenix

Certified Scrum Master

Certifed Ethical Hacker

Microsoft MVP for ASP.NET

6 years in public accounting

13 years in software development and consulting


Taughtworks, Inc.

Microsoft Certified Partner for Learning Solutions

2/F Liberty Plaza Building, H. V. Dela Costa Street, Makati City


Our New Office

5/F 6784 Ayala Avenue corner V.A. Rufino Street, Makati City


http://en.wikipedia.org/wiki/Ayala_Avenue

http://en.wikipedia.org/wiki/Ayala_Avenue

AgendaSoftware As A Service For Small Businesses

Procurement and Inventory Management

Sales Order and Invoicing Management

Customer Relationship Management

Technologies

Python, Django, Memcache, & Postgresql

Deployment and Maintenance


Primogul

Procurement Inventory Sales Order Sales Invoice Customer Relation

050100150200

2007 2008 2009 2010

Cost Revenue

Reports and Analytics Engines


Procurement

Maintain information about vendors

Use purchase orders to order inventory items

Manage receipts of goods

Manage billings from vendors


Inventory

Manage inventory information, location and movements

Physical inventory count

Inventory worksheets

Inventory adjustments

Inventory valuation


Sales Order

Create quotations for customers

Convert quotations to sales invoice or order

Create sales orders

Allocate inventory items to sales orders


Sales Invoice

Invoice customers for delivered goods or services


Software As A Service

Software on-demand

Multi-tenant environment

Pricing is based on number of seats and usage parameters


Technologies

Python

Django

Postgresql

Memcache


Python 101


Python

Powerful and easy to learn programming language

Requires an interpreter to run

Python interpreter and libraries can be downloaded from python.org

Runs on Mac OS X, Unix, and Windows


Invoking the InterpreterAllan-Spartacus-Mangunes-MacBook-Pro:~ allan$ pythonPython 2.7.2 (default, Jun 20 2012, 16:23:33) [GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwinType "help", "copyright", "credits" or "license" for more information.>>>


Variables

The equal (‘=’) sign is used to assign a value

length = 40

A value can be assigned to several variables

a = b = c = d = 6

A variable must be assigned with a value prior to using it


ListsExpressed a list of values separated by a comma

Placed between square brackets [ ]

Can be of different types

x = [‘hello’, ‘world’, 101, 88]

Indices begins at 0

x[0] equals ‘hello’

x[3] equals 88


Control Flow

while statement

if statement

for statement


while Statement

while loop executes while the condition is true

Example

while {condition}: {run the code} {have it indented}

>>> x, y = 0, 1>>> while y < 12:... print y... x, y = y, x+y... 112358


if Statement

If the condition is true, the code block is executed

Example

if {condition}: {run the code} {have it indented}

>>> a = int(raw_input('Please enter a number: '))Please enter a number: 24>>> if a < 0:... print "You entered a number lower than zero"... else:... print "You entered a number greater than zero"... You entered a number greater than zero

>>> a = int(raw_input('Please enter a number: '))Please enter a number: 0>>> if a < 0:... print "You entered a number lower than zero"... elif a == 0:... print "You entered a number zero"... else:... print "You entered a number greater than zero"... You entered a number zero


for Statement

Iterates over the items

Example

for {i in list}: {run the code} {have it indented}

>>> list = ['dog', 'cat', 'mouse']>>> for i in list:... print i, len(i)... dog 3cat 3mouse 5


Functions

Define

Example

def foo(arguments): {run the code} {have it indented}

>>> def foo(num):... x, y = 0, 1... while y < num:... print y... x, y = y, x+y... >>> foo(20)11235Friday, January 18, 13

ClassesBlueprint of an object

Provide the fundamental features of Object-Oriented Programming

Can inherit from multiple base classes

An instance can be modified during runtime

Data members and member methods are public.

Member methods are virtual

Conventions tells us that member that begins with an underscore ‘_’ shall be treated as private


Class Definition/InstanceSimplest form:

Statements inside a class are usually method definitions

class Foo:<statement_1>...<statement_2>

class Foo: def bar(num): x, y = 0, 1 while y < num: print y x, y = y, x+y


Django 101


Django

“Web framework for for perfectionists with deadlines” - djangoproject.com

High-level Python Web framework


Django Framework

Object-relational mapper - Define data models entirely in Python

Automatic admin interface - Production-ready user interface to add/update contents

Elegant URL design - cruft-free URL

Template system - Extensible template language

Cache system - Hooked into memcache

Internalization - Multi-language support Source: djangoproject.com


Sites that Use Django

Disqus

Instagram

Mozilla

OpenStack

Pinterest

PolitiFact.com

RdioSource: djangoproject.com


Installing DjangoRequires Python

python.org

Usually installed on Mac OS X, Other Unix system

You may need to set up your database engine like Postgresql, Mysql or Oracle

Install a version for specific operating system

Get the official release

Latest version is 1.4.3

python > import djangoFriday, January 18, 13

Creating Django app

Auto-generate the code to establish the project

Create a project directory

Project structure

django-admin.py startproject blog

demo/manage.pyblog/

__init__.pysettings.pyurls.pywsgi.py


Django Development Server

Lightweight web server written in Python

You can use this during development

Don’t use this server in the production

Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$ python manage.py runserverValidating models...

0 errors foundDjango version 1.4.1, using settings 'blog.settings'Development server is running at http://127.0.0.1:8000/


http://127.0.0.1:8000

http://127.0.0.1:8000

Setting up DatabaseEdit the blog/settings.py

Python module that contains Django settings

Change the keys in the DATABASESDATABASES = { 'default': { 'ENGINE': 'django.db.backends.sqlite3', # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'. 'NAME': '/Users/allan/demo/blog/blog.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

Holds the names of activated applications

Each app holds one database table

INSTALLED_APPS = ( 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.sites', 'django.contrib.messages', 'django.contrib.staticfiles',)

Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$ python manage.py syncdbCreating tables ...Creating table auth_permissionCreating table auth_group_permissionsCreating table auth_groupCreating table auth_user_user_permissionsCreating table auth_user_groupsCreating table auth_userCreating table django_content_typeCreating table django_sessionCreating table django_site


ModelsProject vs App

An App is a web application that contains functionalities

A Project is a collection of Apps

To create an App

The entries/ directory holds the blog entries application

Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$ python manage.py startapp entriesAllan-Spartacus-Mangunes-MacBook-Pro:blog allan$ ls entries__init__.py! models.py! tests.py!views.py


Models

Define models

database layouts with metadata

Edit entries/models.py

The model tells Django to create the db schema and database-access API

from django.db import models

class Entry(models.Model): text = models.CharField(max_length=2000) pub_date = models.DateTimeField('date published')


Model activation

Edit the settings.py file and add ‘entries’

Create the tables

INSTALLED_APPS = ( 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.sites', 'django.contrib.messages', 'django.contrib.staticfiles', 'entries' )

Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$ python manage.py sql entriesBEGIN;CREATE TABLE "entries_entry" ( "id" integer NOT NULL PRIMARY KEY, "text" varchar(2000) NOT NULL, "pub_date" datetime NOT NULL);COMMIT;

Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$ python manage.py syncdbCreating tables ...Creating table entries_entryInstalling custom SQL ...Installing indexes ...Installed 0 object(s) from 0 fixture(s)Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$


Activating Admin SiteNot activated by default

To activate:

Uncomment ‘django.contrib.admin’ in the INSTALLED_APPS

Edit the blog/urls.py

INSTALLED_APPS = ( 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.sites', 'django.contrib.messages', 'django.contrib.staticfiles',

'django.contrib.admin',)

Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$ python manage.py syncdbCreating tables ...Creating table django_admin_logInstalling custom SQL ...Installing indexes ...Installed 0 object(s) from 0 fixture(s)

# Uncomment the next two lines to enable the admin:from django.contrib import adminadmin.autodiscover()

Allan-Spartacus-Mangunes-MacBook-Pro:blog allan$ python manage.py runserverValidating models...

0 errors found


Setting up Views

Represented by a Python function

Requires you to set up the URL in the URLconf module

ROOT_URLCONF setting

Edit blog/urls.py

ROOT_URLCONF = 'blog.urls'

urlpatterns = patterns('', url(r'^entries/$', 'entries.views.index'), # Uncomment the next line to enable the admin: url(r'^admin/', include(admin.site.urls)),)


Setting up Views

Write a view function on entries/views.py

Create a template file

from django.template import Context, loaderfrom entries.models import Entryfrom django.http import HttpResponse

def index(request): latest_entry_list = Entry.objects.all().order_by('-pub_date')[:5] t = loader.get_template('entries/index.html') c = Context({ 'latest_entry_list': latest_entry_list }) return HttpResponse(t.render(c))

TEMPLATE_DIRS = ( '/Users/allan/demo/blog/templates',)

{% if latest_entry_list %} <ul> {% for entry in latest_entry_list %} <li><a href="/entries/{{entry.id}}">{{entry.text}}</a></li> {% endfor %} </ul>{% endif %}


Q and A


Allan Spartacus [email protected]/mangune


mailto:[email protected]

mailto:[email protected]

THANK YOU


developing software as a service app with python & django

Documents

example x

number greater

number lower

number of seats

number zerofriday

different types x

example list

sales ordersfriday