Sams teach yourself django in 24 hours mar 2008 ISBN 067232959x

Part I, "Creating the Website Framework," covers the basics of installing, configuring, and using the Django framework to build basic websites.. What You'll Learn in This Hour What the D

by Brad Dayley

Publisher: Sams Pub Date: February 20, 2008 Print ISBN-10: 0-672-32959-X Print ISBN-13: 978-0-672-32959-3 eText ISBN-10: 0-7686-8033-6 eText ISBN-13: 978-0-7686-8033-1 Pages: 528

Table of Contents | Index

Overview

In just 24 lessons of one hour or less, you will be able to buildfull-featured production websites using Django, the powerfulweb development framework based on Python

Designed for experienced website developers who have at leastsome familiarity with the Python programming language, thisbook uses a straightforward, step-by-step approach Each

lesson builds on the previous ones, enabling you to learn theessentials of implementing the Django framework on a websitefrom the ground up

Step-by-step instructions carefully walk you through the mostcommon Django tasks

Q&As, quizzes, and exercises at the end of each lesson help youtest your knowledge

Notes and tips point out shortcuts and solutions

Learn how to…

Install and configure the Django web development

framework

Implement site interfaces with build templates and viewsUtilize templates and views to store, access, and retrievedata

Use the Django forms library

Define custom tags and filters to minimize coding

Secure sites with registration, authorization, logins, andpermissions

Manage sessions and cookies

Implement middleware for request and response handlingCreate sitemaps to inform search engines of your contentInternationalize your site

Hour 8: Using Built-in Template Tags to Enhance Views 139Hour 9: Using Built-in Template Filters to Enhance Views 155Hour 10: Adding Forms to Views 185

Hour 11: Using Views to Add and Update Data in the Database209

Appendix B: Django Form Field Objects 481Appendix C: Formatting Dates and Times 491Index 493

Adding, Modifying, and Viewing Objects in the AdminInterface

Creating a Template

Rendering a Template as an HTTP Response

Extending Templates

Workshop

Exercises

Hour 11 Using Views to Add and Update Data in theDatabase

Handling GET and POST Requests

Validating Data from a POST Against the ModelUpdating Data in the Database

Understanding How to Use RequestContexts in TemplatesSummary

Overriding Block Tags in a Custom Admin TemplateOverriding the Built-in Admin Views in the URLconf FileSummary

Exercises

Hour 20 Internationalization and LocalizationLocalizing Strings in Python

Form Field to Model Field MappingAppendix C Formatting Dates and TimesTry It Yourself

Index

Warning and Disclaimer

Bulk Sales

Sams Publishing offers excellent discounts on this book whenordered in quantity for bulk purchases or special sales For

Brad Dayley is a senior software engineer in Novell's Product

Development Group He has 16 years of experience in

designing, developing, and implementing software from thekernel level through web development He is the author of

several books on server and network management as well asprogramming languages When he is not developing software orwriting books, he can be found biking, hiking, and/or Jeepingsomewhere in the remote regions of the western United Stateswith his wife, DaNae, and four sons

My sincere gratitude goes out to the following persons, withoutwhom this book could not have happened:

My wife, who provides the inspiration and strength behind

everything I do Thank you for being everything for me

My friends, who force me to be more intelligent and creativethan I necessarily would like to be

My editors, who made the book readable, technically accurate,and kept me on track It seems that nothing gets by you

Thanks to Songlin Qiu for all your hard work in keeping me onthe right track and ensuring the quality of the book is the best.Thanks to Gayle Johnson for making it appear as though I canactually write Thanks to Tim Boronczyk for making sure thebook is technically useful as well as technically accurate Thanks

to Jovana San Nicolas-Shirley and Gina Kanouse for seeing methrough to the end Last but not least, thanks to Mark Taber forgetting the book off the ground and making it happen All ofyou are the best

As the reader of this book, you are our most important critic

and commentator We value your opinion, and we want to knowwhat we're doing right, what we could do better, what areasyou'd like to see us publish in, and any other words of wisdomyou're willing to pass our way

You can email or write us directly to let us know what you did ordidn't like about this book—as well as what we can do to makeour books stronger

Please note that we cannot help you with technical problems related to the topic of this book, and that we might not be able

to reply to every message.

When you write, please be sure to include this book's title andauthor, as well as your name and phone number or email

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Mail: Sams Publishing

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Visit our website and register this book at informit.com/registerfor convenient access to any updates, downloads, or errata thatmight be available for this book

I have been working with the Django framework for about ayear and a half, and I love it Every so often you run into ideasthat make absolute, complete sense, and Django is one of

those The folks at Django seem to be bent on making it themost elegant web framework available, and so far they are

doing a great job

This was a tough book to write The Django framework is simple

to implement, but you can accomplish so much with it The

format of this book is Teach Yourself in 24 Hours The idea isthat after spending 24 hours with this book and a Django

installation, you should have a pretty good idea of how to useDjango to build a full-featured production website

Throughout this book, I use a fictitious website project callediFriends to illustrate the building blocks of a Django-poweredwebsite The book has several "Try It Yourself" sections thattake you through specific tasks of building the iFriends website

Actually do the "Try It Yourself" sections They will help

everything else make a lot more sense They build on each

other, so if you skip one, future "Try It Yourself" sections maynot work properly

When you have finished the "Try It Yourself" sections, you willhave a mostly functional website You should easily have

enough skills by then that you could tweak and finish the

website on your own in only a few hours if you wanted to Therejust wasn't enough room in the book to finish every component

I felt it was much more important to cover the topics that I did

I do have one disclaimer: There is absolutely no CSS code in

my HTML template examples I would much rather have usedCSS code to format my HTML templates than the classic HTMLtags (some of them deprecated) that I used I chose not to

include CSS for two important reasons The first reason is room.Adding CSS files to all the examples would have taken quite a

techniques belong in a different book

When designing the content for this book, I tried to come upwith the most relevant way to present the Django frameworkthat will actually help programmers develop websites that arepertinent to real-world needs I know that a few componentsand concepts have been left out I welcome your comments andany suggestions on things that you feel need to be added to thisbook If I get a chance, I will try to incorporate them into futurerevisions of the book You can email any queries or suggestions

to dayleybooks@yahoo.com

I hope you enjoy the Django framework as much as I have andthat the concepts in this book prove useful to you

Who Should Read This Book

This book should be read by anyone who is developing or evenconsidering developing websites The Django framework savesweb developers a lot of time and headaches This book is

designed for website developers who have at least some

familiarity with the Python programming language Don't worry

if you are not very familiar with Python You should be able topick up on what is going on with a few visits to

www.python.org

I have been working with the Django framework for about ayear and a half, and I love it Every so often you run into ideasthat make absolute, complete sense, and Django is one of

those The folks at Django seem to be bent on making it themost elegant web framework available, and so far they are

doing a great job

This was a tough book to write The Django framework is simple

to implement, but you can accomplish so much with it The

format of this book is Teach Yourself in 24 Hours The idea isthat after spending 24 hours with this book and a Django

installation, you should have a pretty good idea of how to useDjango to build a full-featured production website

Throughout this book, I use a fictitious website project callediFriends to illustrate the building blocks of a Django-poweredwebsite The book has several "Try It Yourself" sections thattake you through specific tasks of building the iFriends website

Actually do the "Try It Yourself" sections They will help

everything else make a lot more sense They build on each

other, so if you skip one, future "Try It Yourself" sections maynot work properly

When you have finished the "Try It Yourself" sections, you willhave a mostly functional website You should easily have

enough skills by then that you could tweak and finish the

website on your own in only a few hours if you wanted to Therejust wasn't enough room in the book to finish every component

I felt it was much more important to cover the topics that I did

I do have one disclaimer: There is absolutely no CSS code in

my HTML template examples I would much rather have usedCSS code to format my HTML templates than the classic HTMLtags (some of them deprecated) that I used I chose not to

include CSS for two important reasons The first reason is room.Adding CSS files to all the examples would have taken quite a

techniques belong in a different book

When designing the content for this book, I tried to come upwith the most relevant way to present the Django frameworkthat will actually help programmers develop websites that arepertinent to real-world needs I know that a few componentsand concepts have been left out I welcome your comments andany suggestions on things that you feel need to be added to thisbook If I get a chance, I will try to incorporate them into futurerevisions of the book You can email any queries or suggestions

to dayleybooks@yahoo.com

I hope you enjoy the Django framework as much as I have andthat the concepts in this book prove useful to you

Who Should Read This Book

This book should be read by anyone who is developing or evenconsidering developing websites The Django framework savesweb developers a lot of time and headaches This book is

designed for website developers who have at least some

familiarity with the Python programming language Don't worry

if you are not very familiar with Python You should be able topick up on what is going on with a few visits to

www.python.org

Part I, "Creating the Website Framework," covers the basics

of installing, configuring, and using the Django framework

to build basic websites You are introduced to the model,template, and view concepts that Django uses to implementwebsites

Part II, "Implementing the Website Interface," covers

building templates and views to build web pages You willlearn how to use templates and views to store, access, andretrieve data that is stored in the website's database

Part III, "Implementing a Full-Featured Website," coversadding authentication, cookie handling, and other featuresnecessary to implement a full production website You willlearn how to create users and groups and how to assignpermissions to specific data

Part IV, "Implementing Advanced Website Components,"covers some of the advanced features of the Django

framework that you will likely want to implement in

production websites You will learn how to implement

middleware to enable advanced request and response

handlers You will also learn how to implement localizedstrings to add multiple-language capability to the website,implement caching to improve website performance, anddeploy a Django website

The Teach Yourself in 24 Hours series has several unique

elements that will help you as you are trying to learn the

Django framework Throughout the book, I use the followingelements to draw attention to specific concepts:

The "Try It Yourself" sections are designed to take you throughthe steps of actually performing the tasks that you have beenreading about Do not skip these sections They usually provideadditional information about the topic and are a great chance to

At the end of each hour, you will find the following sections thatare designed to help you solidify what you have read:

The "Q&A" section poses questions and gives answers onconcepts that are related to the hour but that fall outsidewhat is covered in the book

The "Quiz" section provides questions and answers aboutthe topics covered in each hour

The "Exercises" section lists activities that you can do topractice what you have learned during the hour These

exercises are a great way to strike out on your own a bitand get more confident with Django

What You'll Learn in This Hour

What the Django framework is, and why you should use it

develop full-featured production websites Django is flexible andmakes it easy to design a website that can be easily updatedand expanded As soon as you have learned the Django

architecture The rest of the hours in this book provide the in-This hour is a basic overview of the Django framework,

What Is Django?

Django is a high-level web framework that simplifies websitedevelopment As a high-level web framework, Django abstractsmuch of the web development process, allowing developers toquickly implement database-backed websites using dynamicweb pages

Did you Know?

Django is pronounced "JAN-go" with the "D" silent

By dynamic, we mean web pages that are built on-the-fly usingdata from the browser request, URL, and a database Dynamicpages solve several different problems The biggest problemthey solve is trying to maintain numerous static pages scatteredall over a classic website

Django implements a Model View Controller (MVC) architecture

to separate the data, logic, and view layers in website

development This has two major advantages One is that it'seasy to have some developers develop the database and othersdevelop the web pages Another is that code and URLs becomemuch cleaner, easier to maintain, and more elegant

What You'll Learn in This Hour

What the Django framework is, and why you should use it

develop full-featured production websites Django is flexible andmakes it easy to design a website that can be easily updatedand expanded As soon as you have learned the Django

architecture The rest of the hours in this book provide the in-This hour is a basic overview of the Django framework,

What Is Django?

Django is a high-level web framework that simplifies websitedevelopment As a high-level web framework, Django abstractsmuch of the web development process, allowing developers toquickly implement database-backed websites using dynamicweb pages

Did you Know?

Django is pronounced "JAN-go" with the "D" silent

By dynamic, we mean web pages that are built on-the-fly usingdata from the browser request, URL, and a database Dynamicpages solve several different problems The biggest problemthey solve is trying to maintain numerous static pages scatteredall over a classic website

Django implements a Model View Controller (MVC) architecture

to separate the data, logic, and view layers in website

development This has two major advantages One is that it'seasy to have some developers develop the database and othersdevelop the web pages Another is that code and URLs becomemuch cleaner, easier to maintain, and more elegant

What You'll Learn in This Hour

What the Django framework is, and why you should use it

develop full-featured production websites Django is flexible andmakes it easy to design a website that can be easily updatedand expanded As soon as you have learned the Django

architecture The rest of the hours in this book provide the in-This hour is a basic overview of the Django framework,

What Is Django?

Django is a high-level web framework that simplifies websitedevelopment As a high-level web framework, Django abstractsmuch of the web development process, allowing developers toquickly implement database-backed websites using dynamicweb pages

Did you Know?

Django is pronounced "JAN-go" with the "D" silent

By dynamic, we mean web pages that are built on-the-fly usingdata from the browser request, URL, and a database Dynamicpages solve several different problems The biggest problemthey solve is trying to maintain numerous static pages scatteredall over a classic website

Django implements a Model View Controller (MVC) architecture

to separate the data, logic, and view layers in website

development This has two major advantages One is that it'seasy to have some developers develop the database and othersdevelop the web pages Another is that code and URLs becomemuch cleaner, easier to maintain, and more elegant

The biggest reason to use Django is that it's easy to set up aproduction website in no time at all As soon as you have

learned how to use Django to build websites, you will be able toimplement basic websites in a matter of hours

Another reason to use Django is that components or even entirewebsites are portable and can be used in other websites Onlyminimal reconfiguration is needed to port the views

Django implements a Python class, django.db.models.Model,

to define data models that will be used in a website A datamodel is a set of definitions that define the attributes of objectsthat will be stored in the database When you build your

website, you create a subclass of the Model class and add

Field members to that class to define specific data Django'smodel interface provides a full-featured selection of field typesthat make it easy to define each model

The models you define in your project are synchronized to anSQL database backend as tables Django also provides a nicedatabase interface that lets you access data in the databasefrom views and templates We will discuss models more in Hour

3, "Adding Models and Objects to Your Website," and Hour 5,

"Using Data from the Database in Views."

Rendering a view from an URL request is a multistep process inDjango When a Django server receives an URL request, it

parses the URL and, using a set of previously defined patterns,determines which Python code should render the view

The way it works is that as you design your website, you writePython functions that will build and render web pages For eachPython function, you define at least one URL pattern that willlink a specific URL to that view function The Django frameworkreceives the URL request, handing the request to the view

function and then sending the dynamically built response back

to the web browser We will discuss the URL configuration more

in Hour 4, "Creating the Initial Views."