book

Django: Web Development with Python

Name: Django: Web Development with Python
ISBN: 9781787121386

by Samuel Dauzon, Aidas Bendoraitis, Arun Ravindran

August 2016

Beginner to intermediate

717 pages

15h 24m

English

Packt Publishing

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Django: Web Development with Python
Table of Contents
Django: Web Development with Python
Django: Web Development with Python
Credits
Preface
What this learning path covers
What you need for this learning path
Who this learning path is for
Reader feedback
Customer support
Downloading the example codeErrataPiracyQuestions

1. Module 1
1. Django's Position on the Web
From Web 1.0 to Web 2.0Web 1.0Web 2.0
What is Django?
Django – a web framework
The MVC framework
Why use Django?
Summary
2. Creating a Django Project
Installing Python 3Installing Python 3 for WindowsInstalling Python 3 for LinuxInstalling Python 3 for Mac OS
Installing setuptools
Installing setuptools for WindowsInstalling setuptools for LinuxInstalling setuptools for Mac OS
Installing PIP
Installing PIP for WindowsInstalling PIP for LinuxInstalling PIP for Mac OS
Installing Django
Installing Django for WindowsInstalling Django for LinuxInstalling Django for Mac OS
Starting your project with Django
Creating an application
Configuring the application
Summary
3. Hello World! with Django
Routing in Django
Regular expressions
The uninterpreted charactersThe beginning and the end of the lineThe any character regular expressionCharacter classesValidating the number of characters
Creating our first URL
Creating our first view
Testing our application
Summary
4. Working with Templates
Displaying Hello world! in a template
Injecting the data from the view to the template
Creating dynamic templates
Integrating variables in templates
Conditional statementsLooping in a template
Using filters
The upper and lower filtersThe lower filterThe upper filterThe capfirst filterThe pluralize filterThe escape and safe to avoid XSS filtersThe linebreaks filterThe truncatechars filter
Creating DRY URLs
Extending the templates
Using static files in templates
Summary
5. Working with Models
Databases and Django
Migrations with South
Installing SouthUsing the South extension
Creating simple models
The UserProfile modelThe Project model
The relationship between the models
Creating the task model with relationships
Extending models
The admin module
Installing the moduleUsing the module
Advanced usage of models
Using two relationships for the same modelDefining the str method
Summary
6. Getting a Model's Data with Querysets
The persisting model's data on the databaseFilling a model and saving it in the database
Getting data from the database
Getting multiple recordsGetting only one recordGetting a model instance from the queryset instance
Using the get parameter
Saving the foreign key
Updating records in the database
Updating a model instanceUpdating multiple records
Deleting a record
Getting linked records
Advanced usage of the queryset
Using an OR operator in a querysetUsing the lower and greater than lookupsPerforming an exclude queryMaking a raw SQL query
Summary
7. Working with Django Forms
Adding a developer without using Django formsTemplate of an HTML formThe view using the POST data reception
Adding a developer with Django forms
CSRF protectionThe view with a Django formTemplate of a Django form
The form based on a model
The supervisor creation form
Advanced usage of Django forms
Extending the validation formCustomizing the display of errorsUsing widgetsSetting initial data in a formWhen instantiating the formWhen defining fields
Summary
8. Raising Your Productivity with CBV
The CreateView CBVAn example of minimalist usage
Working with ListView
An example of minimalist usageExtending ListView
The DetailView CBV
An example of minimalist usageExtending DetailView
The UpdateView CBV
An example of minimalist usageExtending the UpdateView CBV
The DeleteView CBV
Going further by extending the CBV
Using a custom class CBV update
Summary
9. Using Sessions
Creating and getting session variablesAn example – showing the last task consulted
About session security
Summary
10. The Authentication Module
How to use the authentication moduleConfiguring the Django applicationEditing the UserProfile model
Adding a user
Login and logout pages
Restricting access to the connected members
Restricting access to viewsRestricting access to URLs
Summary
11. Using AJAX with Django
Working with jQuery
jQuery basics
CSS selectors in jQueryGetting back the HTML contentSetting HTML content in an elementLooping elementsImporting the jQuery library
Working with AJAX in the task manager
Summary
12. Production with Django
Completing the development
Selecting the physical server
Selecting the server software
Selecting the server database
Deploying the Django website
Installing PIP and Python 3Installing PostgreSQLInstalling virtualenv and creating a virtual environment
Installing Django, South, Gunicorn, and psycopg2
Configuring PostgreSQLAdaptation of Work_manager to productionInitial South migrationUsing GunicornStarting Nginx
Summary
A. Cheatsheet
The field types in modelsThe numerical field typeThe string field typeThe temporal field typeOther types of fieldsRelationship between modelsThe model meta attributesOptions common to all fields of models
The form fields
Common options for the form fieldsThe widget formError messages (forms and models)
The template language
Template tagsLoops in dictionariesConditional statementsThe template filtersThe queryset methods
2. Module 2
1. Getting Started with Django 1.8
Introduction
Working with a virtual environment
Getting readyHow to do it…How it works…See also
Creating a project file structure
Getting readyHow to do it…How it works…See also
Handling project dependencies with pip
Getting readyHow to do it…How it works…There's more…See also
Making your code compatible with both Python 2.7 and Python 3
Getting readyHow to do it…How it works…
Including external dependencies in your project
Getting readyHow to do it…How it works…See also
Configuring settings for development, testing, staging, and production environments
Getting readyHow to do it…How it works…See also
Defining relative paths in the settings
Getting readyHow to do it…How it works…See also
Creating and including local settings
Getting readyHow to do it…How it works…See also
Setting up STATIC_URL dynamically for Subversion users
Getting readyHow to do it…How it works…See also
Setting up STATIC_URL dynamically for Git users
Getting readyHow to do it…How it works…See also
Setting UTF-8 as the default encoding for MySQL configuration
Getting readyHow to do it…How it works…
Setting the Subversion ignore property
Getting readyHow to do it…How it works…See also
Creating the Git ignore file
Getting readyHow to do it…How it works…See also
Deleting Python-compiled files
Getting readyHow to do it…How it works…See also
Respecting the import order in Python files
Getting readyHow to do it…How it works…There's more…See also
Creating app configuration
Getting readyHow to do it…How it works…There is more…See also
Defining overwritable app settings
Getting readyHow to do it…How it works…
2. Database Structure
Introduction
Using model mixins
Getting readyHow to do it…How it works…There's more…See also
Creating a model mixin with URL-related methods
Getting readyHow to do it…How it works…See also
Creating a model mixin to handle creation and modification dates
Getting readyHow to do it…How it works…See also
Creating a model mixin to take care of meta tags
Getting readyHow to do it…How it works…See also
Creating a model mixin to handle generic relations
Getting readyHow to do it…How it works…See also
Handling multilingual fields
Getting readyHow to do it…How it works…
Using migrations
Getting readyHow to do it…How it works…See also
Switching from South migrations to Django migrations
Getting readyHow to do it…How it works…See also
Changing a foreign key to the many-to-many field
Getting readyHow to do it…How it works…See also
3. Forms and Views
Introduction
Passing HttpRequest to the form
Getting readyHow to do it…How it works…See also
Utilizing the save method of the form
Getting readyHow to do it…How it works…See also
Uploading images
Getting readyHow to do it…How it works…There's moreSee also
Creating a form layout with django-crispy-forms
Getting readyHow to do it…How it works…There's more…See also
Downloading authorized files
Getting readyHow to do it…How it works…See also
Filtering object lists
Getting readyHow to do it…How it works…See also
Managing paginated lists
Getting readyHow to do it…How it works…See also
Composing class-based views
Getting readyHow to do it…How it works…There's more…See also
Generating PDF documents
Getting readyHow to do it…How it works…See also
Implementing a multilingual search with Haystack
Getting readyHow to do it…How it works…See also
4. Templates and JavaScript
Introduction
Arranging the base.html template
Getting readyHow to do it…How it works…See also
Including JavaScript settings
Getting readyHow to do it…How it works…See also
Using HTML5 data attributes
Getting readyHow to do it…How it works…See also
Opening object details in a modal dialog
Getting readyHow to do it…How it works…See also
Implementing a continuous scroll
Getting readyHow to do it…How it works…See also
Implementing the Like widget
Getting readyHow to do it…How it works…See also
Uploading images by Ajax
Getting readyHow to do it…How it works…See also
5. Custom Template Filters and Tags
Introduction
Following conventions for your own template filters and tags
How to do it...
Creating a template filter to show how many days have passed since a post was published
Getting readyHow to do it...How it works...There's more...See also
Creating a template filter to extract the first media object
Getting readyHow to do it...How it works...There's more...See also
Creating a template filter to humanize URLs
Getting readyHow to do it...How it works...See also
Creating a template tag to include a template if it exists
Getting readyHow to do it...How it works...There's more...See also
Creating a template tag to load a QuerySet in a template
Getting readyHow to do it...How it works...See also
Creating a template tag to parse content as a template
Getting readyHow to do it...How it works...See also
Creating a template tag to modify request query parameters
Getting readyHow to do it...How it works...See also
6. Model Administration
Introduction
Customizing columns on the change list page
Getting readyHow to do it...How it works...There's more...See also
Creating admin actions
Getting readyHow to do it...How it works...See also
Developing change list filters
Getting readyHow to do it...How it works...See also
Customizing default admin settings
Getting readyHow to do it...How it works...There's more...See also
Inserting a map into a change form
Getting readyHow to do it...How it works...See also
7. Django CMS
Introduction
Creating templates for Django CMS
Getting readyHow to do it...How it works...See also
Structuring the page menu
Getting readyHow to do it...How it works...See also
Converting an app to a CMS app
Getting readyHow to do it...How it works...See also
Attaching your own navigation
Getting readyHow to do it...How it works...See also
Writing your own CMS plugin
Getting readyHow to do it...How it works...See also
Adding new fields to the CMS page
Getting readyHow to do it...How it works...See also
8. Hierarchical Structures
Introduction
Creating hierarchical categories
Getting readyHow to do it...How it works...See also
Creating a category administration interface with django-mptt-admin
Getting readyHow to do it...How it works...See also
Creating a category administration interface with django-mptt-tree-editor
Getting readyHow to do it...How it works...See also
Rendering categories in a template
Getting readyHow to do it...How it works...There's more...See also
Using a single selection field to choose a category in forms
Getting readyHow to do it...How it works...See also
Using a checkbox list to choose multiple categories in forms
Getting readyHow to do it...How it works...See also
9. Data Import and Export
Introduction
Importing data from a local CSV file
Getting readyHow to do it...How it works...There's more...See also
Importing data from a local Excel file
Getting readyHow to do it...How it works...There's more...See also
Importing data from an external JSON file
Getting readyHow to do it...How it works...See also
Importing data from an external XML file
Getting readyHow to do it...How it works...There's more...See also
Creating filterable RSS feeds
Getting readyHow to do it...How it works...See also
Using Tastypie to create API
Getting readyHow to do it...How it works...See also
Using Django REST framework to create API
Getting readyHow to do it...How it works...See also
10. Bells and Whistles
Introduction
Using the Django shell
Getting readyHow to do it...How it works...See also
Using database query expressions
Getting readyHow to do it...How it works...See also
Monkey-patching the slugify() function for better internationalization support
Getting readyHow to do it...How it works...There's more...See also
Toggling the Debug Toolbar
Getting readyHow to do it...How it works...See also
Using ThreadLocalMiddleware
Getting readyHow to do it...How it works...See also
Caching the method return value
Getting readyHow to do it...How it works...See also
Using Memcached to cache Django views
Getting readyHow to do it...How it works...See also
Using signals to notify administrators about new entries
Getting readyHow to do it...How it works...See also
Checking for missing settings
Getting readyHow to do it...How it works...See also
11. Testing and Deployment
Introduction
Testing pages with Selenium
Getting readyHow to do it...How it works...See also
Testing views with mock
Getting readyHow to do it...How it works...See also
Testing API created using Django REST framework
Getting readyHow to do it...How it works...See also
Releasing a reusable Django app
Getting readyHow to do it...How it works...See also
Getting detailed error reporting via e-mail
Getting readyHow to do it...How it works...See also
Deploying on Apache with mod_wsgi
Getting readyHow to do it...How it works...There's more...See also
Setting up cron jobs for regular tasks
Getting readyHow to do it...How it works...See also
Creating and using the Fabric deployment script
Getting readyHow to do it...How it works...There's more...See also
3. Module 3
1. Django and Patterns
How does Django work to?
What is a Pattern?
Gang of Four PatternsIs Django MVC?Fowler's PatternsAre there more patterns?
Patterns in this book
Criticism of PatternsHow to use Patterns
Best practices
Python Zen and Django's design philosophy
Summary
2. Application Design
How to gather requirements
Are you a story teller?
HTML mockups
Designing the application
Dividing a project into AppsReuse or roll-your-own?My app sandboxWhich packages made it?
Before starting the project
SuperBook – your mission, should you choose to accept it
Why Python 3?Starting the project
Summary
3. Models
M is bigger than V and C
The model hunt
Splitting models.py into multiple files
Structural patterns
Patterns – normalized modelsProblem detailsSolution detailsThree steps of normalizationFirst normal form (1NF)Second normal form or 2NFThird normal form or 3NFDjango modelsPerformance and denormalizationShould we always normalize?Pattern – model mixinsProblem detailsSolution detailsModel mixinsPattern – user profilesProblem detailsSolution detailsSignalsAdminMultiple profile typesPattern – service objectsProblem detailsSolution details
Retrieval patterns
Pattern – property fieldProblem detailsSolution detailsCached propertiesPattern – custom model managersProblem detailsSolution detailsSet operations on QuerySetsChaining multiple QuerySets
Migrations
Summary
4. Views and URLs
A view from the topViews got classier
Class-based generic views
View mixins
Order of mixins
Decorators
View patterns
Pattern – access controlled viewsProblem detailsSolution detailsPattern – context enhancersProblem detailsSolution detailsPattern – servicesProblem detailsSolution details
Designing URLs
URL anatomyWhat happens in urls.py?The URL pattern syntaxMnemonic – parents question pink action-figuresNames and namespacesPattern orderURL pattern stylesDepartmental store URLsRESTful URLs
Summary
5. Templates
Understanding Django's template language featuresVariablesAttributesFiltersTagsPhilosophy – don't invent a programming language
Organizing templates
Support for other template languages
Using Bootstrap
But they all look the same!
Template patterns
Pattern – template inheritance treeProblem detailsSolution detailsPattern – the active linkProblem detailsSolution detailsA template-only solutionCustom tags
Summary
6. Admin Interface
Using the admin interface
Enhancing models for the admin
Not everyone should be an admin
Admin interface customizations
Changing the headingChanging the base and stylesheetsAdding a Rich Text Editor for WYSIWYG editingBootstrap-themed adminComplete overhauls
Protecting the admin
Pattern – feature flagsProblem detailsSolution details
Summary
7. Forms
How forms workForms in DjangoWhy does data need cleaning?
Displaying forms
Time to be crisp
Understanding CSRF
Form processing with Class-based views
Form patterns
Pattern – dynamic form generationProblem detailsSolution detailsPattern – user-based formsProblem detailsSolution detailsPattern – multiple form actions per viewProblem detailsSolution detailsSeparate views for separate actionsSame view for separate actionsPattern – CRUD viewsProblem detailsSolution details
Summary
8. Dealing with Legacy Code
Finding the Django versionActivating the virtual environment
Where are the files? This is not PHP
Starting with urls.py
Jumping around the code
Understanding the code base
Creating the big picture
Incremental change or a full rewrite?
Write tests before making any changes
Step-by-step process to writing tests
Legacy databases
Summary
9. Testing and Debugging
Why write tests?
Test-driven development
Writing a test case
The assert methodWriting better test cases
Mocking
Pattern – test fixtures and factories
Problem detailsSolution details
Learning more about testing
Debugging
Django debug pageA better debug page
The print function
Logging
The Django Debug Toolbar
The Python debugger pdb
Other debuggers
Debugging Django templates
Summary
10. Security
Cross-site scripting (XSS)Why are your cookies valuable?How Django helpsWhere Django might not helpCross-Site Request Forgery (CSRF)How Django helpsWhere Django might not helpSQL injectionHow Django helpsWhere Django might not helpClickjackingHow Django helpsShell injectionHow Django helpsAnd the list goes on
A handy security checklist
Summary
11. Production-ready
Production environmentChoosing a web stackComponents of a stack
Hosting
Platform as a serviceVirtual private serversOther hosting approaches
Deployment tools
FabricTypical deployment stepsConfiguration management
Monitoring
Performance
Frontend performanceBackend performanceTemplatesDatabaseCachingCached session backendCaching frameworksCaching patterns
Summary
A. Python 2 versus Python 3
But I still use Python 2.7!
Python 3
Python 3 for DjangonautsChange all the __unicode__ methods into __str__All classes inherit from the object classCalling super() is easierRelative imports must be explicitHttpRequest and HttpResponse have str and bytes typesException syntax changes and improvementsStandard library reorganizedNew goodiesUsing Pyvenv and PipOther changes
Further information
A. Bibliography
Index

Content preview from Django: Web Development with Python

Chapter 6. Getting a Model's Data with Querysets

Querysets are used for data retrieval rather than for constructing SQL queries directly. They are part of the ORM used by Django. An ORM is used to link the view and controller by a layer of abstraction. In this way, the developer uses object model types without the need to write a SQL query. We will use querysets to retrieve the data we have stored in the database through models. These four operations are often summarized by CRUD (Create, Read, Update, and Delete).

The discussed examples in this chapter are intended to show you how the querysets work. The next chapter will show you how to use forms, and thus, how to save data sent from a client in the models.

By the end of this chapter, we will ...

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Advanced Web Development in Python with Django

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Django: Web Development with Python

by Samuel Dauzon, Aidas Bendoraitis, Arun Ravindran

Chapter 6. Getting a Model's Data with Querysets

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