Web Development With Python - Django

8/2/2019 Web Development With Python - Django

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Web developement withPython: Django framework +

DeploymentDavid Jeli (FOI OSS)"

RV FOI


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virtualenv

virtualenvwrapper

pip

Django

Django deployment


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virtualenv

created by Ian Bicking

tool to create isolated Python environments

solution for:

dependencies and version problem

inaccessible global site-packages install application and leave it be?

environments isolated from each other has its own installation directories

doesnt share libraries between envs

doesnt access globally installed libraries


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virtualenv

$sourceENV/bin/activate

(ENV)$python-c"importsys;print

sys.path

['','/Users/djelic/Development/ENV/lib/python2.7/site-packages/setuptools-0.6c11-

py2.7.egg,]$deactivate

$


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virtualenv

use --no-site-packages (default)

use --system-site-packages to inherit globalpackages

relocatable environments (experimental) relocatable

your code doesnt need to be located inside virtualenvironment path!


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virtualenv

Demo


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virtualenvwrapper

set of extensions for virtualenv

wrappers for creating and deleting virtualenvs

managing development workflow

easier to work on more than one project

working on projects without conflicts in projectdependencies

virtualenvwrapper depends on virtualenv


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virtualenvwrapper

$pipinstallvirtualenvwrapper

exportWORKON_HOME=$HOME/.virtualenvs

source/usr/local/bin/virtualenvwrapper.sh


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virtualenvwrapper

switching between environments

user-configurable hooks!

tab completion

import libraries from global Python path


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virtualenvwrapper

transparent workvirtualenv

mkvirtualenv rmvirtualenv workon add2virtualenv

cdsitepackages cdvirtualenv deactivate

user-configurable hooks

postmkvirtualenv

prermvirtualenv postrmvirtualenv

postactivate predeactivate

postdeactivate


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virtualenvwrapper

Demo


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pip

another tool created by Ian Bicking

tool for installing and managing Python packages

Python Package Index (http://pypi.python.org/pypi)

20410 packages

easy_install replacement

support for VCS

most nutritious when used with virtualenv


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pip vs. easy_install

all packages are downloaded before installation

produces useful output

keeps track of why some package is required

easier to use programmatically

native support for VCS (Git, Mercurial, Baazar)

uninstalation of packages

requirements file


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pip vs. easy_install

pip cannot install from eggs, only from source

pip doesnt understand setuptools extras

pip is incompatible with some packages that

extensively customize distutils or setuptools in theirsetup.py files


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pip

install packages

$pipinstallsimplejson[...progressreport...]Successfullyinstalledsimplejson

uninstall packages

$pipuninstallsimplejsonUninstallingsimplejson:

/home/me/env/lib/python2.7/site-packages/simplejson/home/me/env/lib/python2.7/site-packages/simplejson-2.2.1-py2.7.egg-infoProceed(y/n)?ySuccessfullyuninstalledsimplejson


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pip

upgrading packages

$pipinstall--upgradesimplejson[...progressreport...]Successfullyinstalledsimplejson

searching for packages (PyPI)

$pipsearchsimplejsonsimplejson-Simple,fast,extensibleJSONencoder/decoderforPython


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pip

bundles

requirements file

MyAppDjango==1.4.0wsgiref==0.1.2-esvn+http://myrepo/svn/MyApp#egg=MyApp

freeze$pipfreeze>requirements.txt

install$pipinstall-r/path/to/requirements.txt


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Django

open source web application framework

written in Python

MVC architectural pattern

originaly developed for news-oriented sites for TheWorld Company

Named after guitarist Django Reinhardt


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Django

The Web framework for perfectionists withdeadlines

emphasis on simplicity, DRY and reuse

pluggable applications majority of the features commuity contributed


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Django

database driven web application

MVC

object-relational mapper (ORM)

Model: relational database

View: processing requests with web templatingsystem

Controller: regular-expression based URL dispatcher


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django.core

core Django framework

standalone development web server

form serialization and validation

middleware classes

internationalization system

caching

system for extending template engine

interface to unit test framework

internal dispatcher system


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django.contrib

authentication system

dynamic administrative interface

tools for generating RSS and Atom feeds

sites framework

commenting system


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Model Syntax

fromdjango.dbimportmodelsclassAnketa(models.Model):

pitanje=models.CharField(max_length=200)pub_date=models.DateTimeField('datepublished')def__unicode__(self):returnself.pitanjeclassOdgovor(models.Model):pitanje=models.ForeignKey(Anketa)odgovor=models.CharField(max_length=200)glasova=models.IntegerField()def__unicode__(self):returnself.odgovor


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Interactive shell

$pythonmanage.pyshell>>>fromanketa.modelsimportAnketa,Odgovor>>>Anketa.objects.all()

[]>>>a=Anketa.objects.get(pk=1)>>>a>>>a.odgovor_set.all()[]>>>o=a.odgovor_set.all()[0]>>>o.glasova1


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Auto-generated admin


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Admin Syntax

fromanketa.modelsimportAnketa,Odgovorfromdjango.contribimportadminclassOdgovorInline(admin.TabularInline):

model=Odgovorextra=3classAnketaAdmin(admin.ModelAdmin):fieldsets=[(None,{'fields':['pitanje']}),('Dateinformation',{'fields':['pub_date'],

'classes':['collapse']}),]inlines=[OdgovorInline]list_display=('pitanje','pub_date')admin.site.register(Anketa,AnketaAdmin)


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URL pattern

urlpatterns=patterns('',url(r'^$','rvdemo.views.home',name='home'),url(r'^rvdemo/',include('rvdemo.anketa.urls')),#OR#url(r'^anketa/$','anketa.views.index'),

url(r'^admin/',include(admin.site.urls)),)


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View Syntax

fromanketa.modelsimportAnketafromdjango.shortcutsimportrender_to_response,get_object_or_404defindex(request):anketa_list=Anketa.objects.all()

returnrender_to_response('anketa/index.html',{'anketa_list':anketa_list})


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Template

{%ifanketa_list%}

{%foranketainanketa_list%}{{anketa.pitanje}}{%endfor%}{%else%}

Nemaanketa.
{%endif%}


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Web Development With Python - Django