Python/Django Training

PYTHON – DJANGO TRAINING BY: BKIT ATOM, Epsilon Mobile @ HCMC HCMUT Summer 2012

Main reference:

https://docs.djangoproject.com/en/1.4/

Contact: bkitatom@gmail.com

Instructors

• Nguyễn Đức Minh Khôi (nguyenducminhkhoi@gmail.com)

• Phạm Trần Xuân Minh (clapika2010@gmail.com)

• Võ Xuân Thịnh (voxuanthinh24492@gmail.com)

• Trần Đăng Khoa (khoatran@epsilon-mobile.com)

• Lê Trung Hiếu (letrunghieu.cse09@gmail.com)

23/08/2012 Python - Django Training Course 2012 @HCMUT 2

Tools - set up

• This training using:

• notepad++ as the main development tool

• command line as the main environment

• Chrome/Firefox with firebug plugin browser

• Notice:

• In some setups you have to set some environment variables, to do this, in windows 7, press: Start > type: env > choose: edit the system environment variable > press: Environment variables button > system variable > choose path fields > add the path to the bin of required soft > press OK OR you just use cmd line: set PATH=path/to/your/bin;

• Some plugin in notepad++: Explorer, Light Explorer, Xbrackets Lite, TextFx, NppExec

Contents

Part 1: Introduction to Python/Django

Part 2: HTML + CSS + JavaScript

Part 3: Installation & Configuration

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 7: URL Configuration and Request/Response (Views)

Part 8: Software development support

Part 9: Django Templates

Part 10: Forms

Part 11: File Uploads and Generic View

Part 12: Other topics

Part 13: Deployment

Introduction to Python/Django - refs

• (1) You can refer to this slides: http://www.mediafire.com/?38s8z3989mh7buj

• (2) Python Basic Concepts slides: https://dl.dropbox.com/u/55056797/Training%20python.pdf

• (3) Or Visit this page for official document from Python.org: http://docs.python.org/archives/python-

2.7.3-docs-pdf-letter.zip

• (4) Python Style Guide: http://www.python.org/dev/peps/pep-0008/

• (5) For more information, visit this book: http://www.djangobook.com/en/2.0/

Introduction to Python/Django

• Outcomes:

• Understand our course‟s outline

• Know the use of Python/Django in today‟s world

• Know some basic concept about python programming language (Built in types, statements, Class, Exception Handling,...)

• Can write some simple python program

Overall Python/Django Course

• Section 1: Getting familiar with Python/Django • Part 1: Introduction to Python/Django • Part 2: HTML + CSS + JavaScript • Part 3: Installation & Configuration • Part 8: Software development support

• Section 2: Understanding Basics Parts: • Part 4: Models • Part 5: QuerySets • Part 7: URL Configuration and Request/Response (Views) • Part 9: Django Templates

• Section 3: Adding functions to your page: • Part 6: Admin Sites • Part 10: Forms • Part 11: File Uploads and Generic View • Part 12: Other topics • Part 13: Deployment

Intro - Python Philosophy

• Beautiful is better than ugly.

• Explicit is better than implicit.

• Simple is better than complex.

• Complex is better than complicated.

• Flat is better than nested.

• Sparse is better than dense.

• Readability counts.

• Special cases aren't special enough to break the rules.

• Although practicality beats purity.

Intro - Python Philosophy (cont.)

• Errors should never pass silently.

• Unless explicitly silenced.

• In the face of ambiguity, refuse the temptation to guess.

• There should be one-- and preferably only one --obvious way to do it.

• Although that way may not be obvious at first unless you're Dutch.

• Now is better than never.

• Although never is often better than right now.

• If the implementation is hard to explain, it's a bad idea.

• If the implementation is easy to explain, it may be a good idea.

• Namespaces are one honking great idea -- let's do more of those!

Web components

Web Dev. Levels

Intro - Django Philosophy

• Loose coupling

• Less code

• Quick development

• Don‟t repeat yourself (DRY)

• Explicit is better than Implicit

• Consistency

• For more, use this document use guide: http://media.readthedocs.org/pdf/django/1.4.X/django.pdf

Intro – Python Exercise

1. Write a program that continually reads integer numbers from the users until the user inputs value 0. After that, print out the average value of input numbers.

2. Write a guess number game. Each launching, the program will generate a random lucky number from 1 to 100. After that, the program will ask the user for a guess number. If the guess number is greater than the lucky number, it will print out “Too high”; if the guess number is less than the lucky number, it will print out “Too low”. The program will continue to ask a new guess number until the user enters the lucky number. As a consequence, it will print out “You guess right! It costs you x guesses”, where x is the number of guesses the user tries.

Intro – Python Exercise (cont.)

3. Write a dictionary program (use Dictionary type). When launching, the users can choose 3 options from the main menu:

a. Search a word

b. Import dictionary

c. Exit

- If the user chooses Search a word, it will require him to enter a word, then, it will print out the definition of this word and return the main menu.

- If the user chooses Import dictionary, it will require him to enter the path of dictionary file. After that, it will import words and definitions in the file into the program dictionary. Finally, it returns the main menu.

- If the user chooses Exit, the program will terminate immediately. The dictionary file is a plain text file with the following format:

Intro – Python Exercise (cont.)

4. Write a student management program (use Class). A student has 5 fields of information: ID, Name, Class, DOB (Date of Birth), GPA (Grade Point Average). The program will have 4 options from the main menu:

a. Explore all students

b. Add new student

c. Remove a student

d. Exit

- Explore all students: prints out all students with their information.

- Add new student: requires the user to enter the information for new student.

- Remove a student: removes a student by ID.

- Exit: terminates the program.

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

HTML + CSS + JavaScript

• (1) HTML + CSS slides: http://www.mediafire.com/?30r202gu4b2csgo

• (2) JavaScript + jQuery slides: http://www.slideshare.net/ducminhkhoi/training-javascript-2012-hcmut

• (3) For complete tutorial and reference, please refer to this page: http://www.w3schools.com/ section

(HTML, HTML5, CSS, CSS3, JavaScript, jQuery, Ajax)

HTML + CSS + JavaScript

• Know some basic concepts about Web infrastructure

• Clearly know about some HTML tags and their functions

• Know some basic CSS attributes and their use

• Know some basic JS statements and clearly know some jQuery statements

• Write a basic form using jQuery/JS to manipulate the information

Exercise

• Write HTML code to make this form

• Add CSS to make align and other styles if you want

• Write JS to check some input fields like this form. If any input fields is wrong, write the alert notice right after

that fields.

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

Installation & Configuration

• You can refer to this documents: http://www.mediafire.com/view/?dwo2133fcpvct16

• Remember to download and install the latest version of the software and tools

• For complete setup, please refer to this site: http://nguyenducminhkhoi.blogspot.com/2011/12/how-to-set-up-environment-for.html

• For complete option of settings.py, refer to this site: https://docs.djangoproject.com/en/1.4/ref/settings/

Installation & Configuration - Outcomes

• Setup successfully according to the guides

• Understand Django Structure Directories and functions.

Exercise

• Complete your own configure and projects.

• Write Hello World project to test your work!

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

Models - References

• (1) Django Models syntax: https://docs.djangoproject.com/en/1.4/topics/db/models/

• (2) Django Models Fields Type https://docs.djangoproject.com/en/1.4/ref/models/fields/

• (3) SQL Wikipedia reference: http://en.wikipedia.org/wiki/SQL

Models - Outcomes

• Understand MVP, MVC Pattern Design

• Understand Django‟s infrastructure

• Know how to mapping a given design database to Django models

• Understand SQL Statements (DML, DDL, Queries)

• Use python manage.py syncdb to sync with database.

MVP Design Pattern

• Django Framework based on MVP Design Pattern

• Model in Django is Model holding database of your website

• View in Django is Template or HTML, that shows your website interface

• Presenter in Django is Views, that control the flow and logic of your website

• So MVP design pattern in Django is MTV

How things in Django works?

Models

• Model:

• Is the single, definitive source of data about your data.

• Contains the essential fields and behaviors of the data you‟re storing.

• Each model maps to a single database table.

• Example:

• The above Person model would create a database table like this:

Models (cont.)

• Review SQL Statements: • DDL (Data Definition Language)

• Query Statements: SELECT columnName,...

FROM tableName,...

WHERE expression

GROUP BY expression

HAVING expression

ORDER BY columnName

Models (cont.)

• Review SQL Statements:

• DML (Data Manipulation Language)

Models (cont.)

• Field types • The database column type (e.g. INTEGER, VARCHAR).

• The widget to use in Django's admin interface, if you care to use it (e.g. <input type="text">,<select>).

• The minimal validation requirements, used in Django's admin and in automatically-generated forms.

Models (cont.)

• Field options

• Each field takes a certain set of field-specific arguments (documented in the model field reference). For example, CharField (and its subclasses) require a max_length argument which specifies the size of the VARCHAR database field used to store the data.

• Examples: null, blank, choices, default, primary_key, unique

• Verbose field names

Models (cont.)

• Relationship:

• Many-to-one:

• use django.db.models.ForeignKey.

• requires a positional argument: the class to which the model is related.

• Many-to-many:

• use ManyToManyField.

Models (cont.)

Can have recursive relationship

Models (cont.)

• One to one: • use OneToOneField

• primary key of an object when that object "extends" another object in some way.

• Models across files:

Models (cont.) • Model methods

• Sample method should define: • __unicode__(): returns a unicode "representation" of any object.

• get_absolute_url(): This tells Django how to calculate the URL for an object.

Models (cont.)

• Override predefined method:

• Notice: • call the superclass method -- that's that super(Blog, self).save(*args,

**kwargs) business -- to ensure that the object still gets saved into the database.

• pass through the arguments that can be passed to the model method -- that's what the *args, **kwargs bit does. Django will, from time to time, extend the capabilities of built-in model methods, adding new arguments.

Models (cont.) • Model fields:

Please refer to: https://docs.djangoproject.com/en/1.4/ref/models/fields/ for more details

Models (cont.) - Homework • Write models.py files for the following database:

• Remember that, this exercise will be used through our homework exercises in our course, so keep in mind this models!

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

QuerySet – references

• (1) Making queries https://docs.djangoproject.com/en/1.4/topics/db/queries/

• (2) QuerySet API reference: https://docs.djangoproject.com/en/1.4/ref/models/querysets/

• (3) Database and project for this section is on: http://www.mediafire.com/?djd76f6uc3ieog5

QuerySet – Outcome

• Make sure after this training, you understand:

QuerySet API

QuerySet –Example1 • We will have 3 model:

#without inheritance from models.Model class

class Student():

id_student = models.IntegerField()

email = models.EmailField()

#without using def __unicode__(self):

class Student2(models.Model):

id_student = models.IntegerField()

#and class student3 with inheritance and __unicode__ function

class Student3(models.Model):

name = models.CharField(max_length=200)

def __unicode__(self):

return 'name: %s and email %s ' % (self.name , self.email)

QuerySet-Using python shell

Let‟s start create some objects!!!

QuerySet-Exercises1:

Using Student3 model, create 35 students who has name is in form: one lowercase letter and its uppercase, email in form “[name]@mysite.com” For example:

QuerySet- with relations Gender_choise = (('m','Male'),('f','Female'))

class Article(models.Model):

gender = models.CharField(max_length=1 ,choices=Gender_choise)

return "article: %s" %self.name

class Song(models.Model):

article = models.ForeignKey(to=Article,related_name='composed')

return "song: %s" %self.name

class Playlist(models.Model):

listmusic = models.ManyToManyField(to=Song,related_name='of_playlist')

return "playlist %s" %self.name

QuerySet-wit relations(2)

QuerySet-with relations (3)

QuerySet- exercises class Publisher(models.Model): name = models.CharField(max_length=30) address = models.CharField(max_length=50) website = models.URLField(blank= True,null=True) def __unicode__(self): return self.name Gender_choise = (('m','Male'),('f','Female')) class Author(models.Model): first_name = models.CharField(max_length=30) last_name = models.CharField(max_length=30) email = models.EmailField() gender = models.CharField(max_length=1,choices=Gender_choise) def __unicode__(self): return "%s %s" %(self.first_name,self.last_name) class Book(models.Model): title= models.CharField(max_length=100) author = models.ManyToManyField(to=Author,related_name="writed") publisher = models.ForeignKey(to=Publisher,related_name="published") publication_date = models.DateField(blank= True,null=True) def __unicode__(self): return self.title

QuerySet – Class exercise

• Print Author‟s name (in order from z to a) and his (her) books.

• Print all Author, who use yahoo mail. (the difference from get and filter)

• Print book that has publisher address is USA

• Print all books that has publisher before 1/1/2012.

• Print books that has been written by women writers.

• Confirm that we already has book that‟s name “Steve Jobs” if not create one.

• Confirm that we already has book that‟s name “Bill Gates” if not create one.

QuerySet – Homework Exercise

• Use the database you designed last week to complete these questions

- Create an app with those models.

- Use shell to complete the following:

• CREATING

+ Create 100 EMPLOYEEs

+ Create 20 PROJECTs

+ Create DEPARTMENTs: HR, IT, marketing, R & D,

QuerySet – Homework Exercise

• RETRIEVING

+ Filter all employees work for HR department

+ Filter all employees work on projects control by IT department

+ Filter all employees that is a supervisor of some other employees

+ Filter all departments that manages by employees that work for project with specific id( you can choose whatever id you want)

• DELETING

+ Delete a given employee with name

+ Delete all Psychology movies

Note: please capture your screens when doing those steps and add them to your report (doc or pdf file).

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

Admin sites (cont.) – reference

• (1) For complete tutorial on setup and running admin sites, visit: https://docs.djangoproject.com/en/1.4/intro/tutorial02/

• (2) For complete document about Django Admin Sites, visit: https://docs.djangoproject.com/en/1.4/ref/contrib/admin/

• (3) And: https://docs.djangoproject.com/en/1.4/ref/contrib/admin/actions/

Admin sites (cont.) - outcomes

• Know how to set up for admin sites

• ModelAdmin Object

• ModelAdmin Option

• ModelAdmin Action

• ModelAdmin Method

• InlineModelAdmin Object

• InlineModelAdmin Option

• Overriding Admin Templates (Optional)

• Adding Custom Validation to admin (Optional)

Admin sites

• “One of the most powerful parts of Django. It reads metadata in your model to provide a powerful and production-ready interface

that content producers can immediately use to start adding content to the site.”

Admin sites (cont.) – setup • How to activate the admin sites mode:

1. Add 'django.contrib.admin' to your INSTALLED_APPS setting.

2. The admin has four dependencies - django.contrib.auth, django.contrib.contenttypes,django.contrib.messages and django.contrib.sessions. If these applications are not in your INSTALLED_APPS list, add them.

3. Add django.contrib.messages.context_processors.messages to TEMPLATE_CONTEXT_PROCESSORS andMessageMiddleware to MIDDLEWARE_CLASSES. (These are both active by default, so you only need to do this if you’ve manually tweaked the settings.)

4. Determine which of your application’s models should be editable in the admin interface.

5. For each of those models, optionally create a ModelAdmin class that encapsulates the customized admin functionality and options for that particular model.

6. Instantiate an AdminSite and tell it about each of your models and ModelAdmin classes.

7. Hook the AdminSite instance into your URLconf.

• visiting the URL you hooked it into (/admin/, by default).

Admin sites (cont.) – ModelAdmin

• The ModelAdmin class is the representation of a model in the admin interface.

• These are stored in a file named admin.py in your application

• If you are happy with the default admin interface, just use:

Admin sites (cont.) – ModelAdmin Options

• ModelAdmin.actions_on_top

• ModelAdmin.actions_on_bottom

• ModelAdmin.actions_selection_counter

• ModelAdmin.date_hierarchy

Admin sites (cont.) – ModelAdmin Actions

• ModelAdmin.exclude

• ModelAdmin.fields

• ModelAdmin.fieldsets

Admin sites (cont.) – ModelAdmin • ModelAdmin.list_display

ModelAdmin.list_display_links ModelAdmin.list_editable

Admin sites (cont.) – ModelAdmin • ModelAdmin.list_filter

• ModelAdmin.search_fields

• ModelAdmin.list_max_show_all

• ModelAdmin.list_per_page

• ModelAdmin.list_select_related

• ModelAdmin.ordering

• ModelAdmin.paginator

• ModelAdmin.save_as

Admin sites (cont.) – InlineModelAdmin

• TabularInline

• StackedInline

• You can edit the books authored by an author on the author page. You add inlines to a model by specifying them in a ModelAdmin.inlines:

• Some InlineModelAdmin options

Admin sites (cont.)

• Overriding admin templates, see more at documents!

Admin sites (cont.) - Homework

Admin page

+ Add all of the models above to admin site.

+ Manage projects of a department by StackInline

+ Manage department managed by an employee by TabularInline

+ Add all below actions to admin page:

- Filter all employees with odd id

- Filter all employees with total timework is more than 40 hours

- Filter all projects which total salary of worker is more than 500usd

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

URLs & Views - reference

• (1) Python regular expression http://docs.python.org/library/re.html#regular-expression-syntax

• (2) URL Dispatcher https://docs.djangoproject.com/en/1.4/topics/http/urls/

• (3) Writing Views: https://docs.djangoproject.com/en/dev/topics/http/views/

• (4) Request and response objects https://docs.djangoproject.com/en/1.4/ref/request-response/

• (5) Render [to response] function: https://docs.djangoproject.com/en/dev/topics/http/shortcuts/#render-to-response

URLs & Views - Outcomes

• Understand some basics python regular expression

• Clearly understand the URL Dispatcher‟s working

• Apply some Request and response objects to simple views and generate a simple website

How things in Django works?

Regular Expressions (RE)

• “A regular expression (or RE) specifies a set of strings that matches it; the functions in this module let you check if a particular string matches a given regular expression”

• Regular expressions can be concatenated to form new regular expressions

• If A and B are both regular expressions, then AB is also a regular expression.

• In general, if a string p matches A and another string q matches B, the string pq will match AB

Some useful REs in Python

• Special characters: „.‟ , „^‟, „$‟, „*‟, „+‟, „?‟, „\‟ , „|‟

• Brackets: {m}, {m, n}, [ab], [0-9], (ab)

• Others: (?P<name>...), \d, \s

• For more information about meanings of above symbols, visit (1)

How to use RE in python

• regular expressions use the backslash character ('\') to indicate special forms or to allow special characters to be used without invoking their special meaning

• string literal prefixed with 'r'

How to use RE in python

URL Dispatcher

• To design URLs for an app, you create a Python module informally called a URLconf (URL configuration).

• This module is pure Python code and is a simple mapping between URL patterns (as simple regular expressions) to Python callback functions (your views).

• Use in urls.py in project and app folder

URL – sample requests explain

• A request to /articles/2005/03/ would match the third entry in the list. Django would call the function news.views.month_archive(request, '2005', '03').

• /articles/2005/3/ would not match any URL patterns, because the third entry in the list requires two digits for the month.

• /articles/2003/ would match the first pattern in the list, not the second one, because the patterns are tested in order, and the first one is the first test to pass. Feel free to exploit the ordering to insert special cases like this.

• /articles/2003 would not match any of these patterns, because each pattern requires that the URL end with a slash.

• /articles/2003/03/03/ would match the final pattern. Django would call the function news.views.article_detail(request, '2003', '03', '03').

URL – non-named/named groups

• non-named regular-expression groups (via parenthesis) to capture bits of the URL and pass them as positional arguments to a view.

• named regular-expression groups to capture URL bits and pass them as keyword arguments to a view.

• the syntax for named regular-expression groups is (?P<name>pattern), where name is the name of the group and pattern is some pattern to match.

• If there are any named arguments, it will use those, ignoring non-named arguments. Otherwise, it will pass all non-named arguments as positional arguments.

URL – non-named/named groups

URL - utility functions

• django.conf.urls utility functions:

• patterns(prefix, pattern_description, ...)

• url(regex, view, kwargs=None, name=None, prefix='')

• include(<module or pattern_list>)

URL – view prefix

URL - Passing extra options to view functions

• In views.py, we have callback function: year_archive(request, year, foo)

Writing views

• View is simply a Python function that takes a Web request and returns a Web response

• This response can be the HTML contents of a Web page, or a redirect, or a 404 error, or an XML document, or an image . . . or anything, really.

• The view itself contains whatever arbitrary logic is necessary to return that response.

Request/ Response

• Django uses request and response objects to pass state through the system.

• HttpRequest objects: • HttpRequest.body

• HttpRequest.path

• HttpRequest.path_info

• HttpRequest.method

• HttpRequest.GET

• HttpRequest.POST

• HttpRequest.FILES

• HttpRequest.META

• HttpRequest.user

• Read more at (4)

Request/ Response (cont.)

• UploadedFile objects

• UploadedFile.name

• UploadedFile.size

• UploadedFile.chunks(chunk_size=None)

• UploadedFile.read(num_bytes=None)

• HttpResponse objects

• In contrast to HttpRequest objects, which are created automatically by Django, HttpResponse objects are your responsibility. Each view you write is responsible for instantiating, populating and returning an HttpResponse.

Request/ Response (cont.)

• Usage:

• HttpResponse subclasses

• class HttpResponseRedirect

• class HttpResponseBadRequest (400)

• class HttpResponseNotFound (404)

• class HttpResponseForbidden (403)

• class HttpResponseServerError (500)

• render(request, template_name[, dictionary][,

context_instance][, content_type][, status][, current_app])

• Combines a given template with a given context dictionary and returns an HttpResponse object with that rendered text.

Django shortcut functions

Django shortcut functions (cont.) • render_to_response(template_name[, dictionary][,

context_instance][, mimetype]) • Renders a given template with a given context dictionary and returns

an HttpResponse object with that rendered text.

Django shortcut functions (cont.)

• redirect(to[, permanent=False], *args, **kwargs):

• Returns an HttpResponseRedirect to the appropriate URL for the arguments passed.

Django shortcut functions (cont.)

Homework

• Write urls.py to map with the following views:

• /employee/?P<e_id> -> employee(id)

• /Department/?P<d_name> -> department()

• /Project/?P<p_name> -> project()

• End in your view, you should implement the exercise in Part 5: QuerySets about employee, department, and project, using render_to_response() function.

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

Dev. Tools - references

• (1) Please refer to this document: http://www.mediafire.com/view/?x074zrdwd40g4u7

Dev. tools - outcomes

• An overview of Software Development Process

• Subversion - Working remotely with team (SVN)

• Project Management Systems (Teamlab)

• Bugs Tracker (Trello)

Software dev. tools Exercise

• You should you at least SVN in your Final Project when working with your partner.

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

Django Templates - reference

• (1) Django template language: https://docs.djangoproject.com/en/1.4/topics/templates/

• (2) Built-in template tags and filters: https://docs.djangoproject.com/en/1.4/ref/templates/builtins/

• (3) If you want to look more technical part, read this: https://docs.djangoproject.com/en/1.4/ref/templates/api/

Django Templates - outcomes

• Understand some basics concepts about django templates and simple HTML view

• Introduce a simple views.py

• Write some code that combines django template and simple view

Templates

• A template is simply a text file

• A template contains:

• Variables: get replaced with values

• Tags: control the logic of the template

• Syntax: {{ variable }}

i = 1, j = 2

class book(models.Model):

title = models.CharField(max_length=50)

author = models.CharField(max_length=35)

obj = book(title = “My life”, author = “Unknow”)

obj can be a non-parametric function

Variable

<h3> {{ obj.title }} </h3> <p> {{ obj.author }} </p>

<h3> My life </h3> <p> Unknow </p>

Filters • Use filters to modify variables for display

• Syntax: {{ variable | filter [| filter …] }}

https://docs.djangoproject.com/en/1.4/ref/templates/builtins

/#ref-templates-builtins-filters

https://docs.djangoproject.com/en/1.4/howto/custom-

template-tags/

<p>{{ value1 | default: "nothing" }}</p> <p> nothing </p>

<p> Length: {{ value2 | length }}</p> <p> Length: 4 </p>

value1 = “” value2 = [1, 4, 2, 6]

• Syntax:

• {% tag %}

• {% tag %} ... tag contents ... {% endtag %}

list = [1, 2, 3, 4] display: List: 1 2 3 4

list = [] display: List is empty

• {# This is a comment #}

{% if list | length > 0 %} List: {% for i in list %} {{ i }} {% endfor %} {% else %} List is empty {% endif %}

Tags: inheritance

• base.html

• template.html

<p>This is a example</p> <title>{% block title %}My site{% endblock %}</title> <div>{% block content %} {% endblock %}</div>

{% extends "base.html" %} {% block title %}Welcome !{% endblock %} {% block content %} <ul> {% for i in [1, 2] %} <li>This is line {{ i }}</li> {% endfor %} </ul> {% endblock %}

Tags: inheritance

• template.html

<p>This is a example</p> <title>Welcome !</title> <div <ul> <li> This is line 1 </li> <li> This is line 2 </li> </ul> </div>

Escape

Example: {{ obj }}

obj = <b>Bold</b>

This will be escaped:

This will not be escaped:

Block autoescape

{% autoescape on %} Example {{ obj }} {% endautoescape %}

{% autoescape off %} Example {{ obj }} {% endautoescape %}

Example <b>Bold</b> Example Bold

Loading templates

setting.py template.html

views.py

TEMPLATE_DIR = ( “mysite/app/template”, “home/default”, )

def viewExample(request, title, author): obj = book(title, author) return render_to_response( “template.html”, {“book” : obj}, context_instance=RequestContext(request))

<p> This is a book </p> <p> Title: {{ book.title }} </p> <p> Author: {{ book.author }}</p>

<p> This is a book </p> <p> Title: My life </p> <p> Author: H.Anh </p>

Django Templates - Exercises

• Write Django Templates for these page:

• Search all employees according to given Name, SSN, Bdates (between X and Y)

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

Forms - references

• (1) Working with forms: https://docs.djangoproject.com/en/1.4/topics/forms/

• (2) Form API: https://docs.djangoproject.com/en/1.4/ref/forms/api/

• (3) FormFields Reference: https://docs.djangoproject.com/en/1.4/ref/forms/fields/

• (4) Form from models: https://docs.djangoproject.com/en/1.4/topics/forms/modelforms/

Forms - Outcomes

• Know how to create a simple form

• Understand how forms are generated and display form in the way you want

• Know how to generate form from a given model

• Know how to make a simple website using form

Form Objects

• A Form object encapsulates a sequence of form fields and a collection of validation rules that must be fulfilled in order for the form to be accepted.

• An unbound form does not have any data associated with it; when rendered to the user, it will be empty or will contain default values.

• A bound form does have submitted data, and hence can be used to tell if that data is valid.

Using Form in a view

• If the form has not been submitted, an unbound instance of ContactForm is

created and passed to the template.

• If the form has been submitted, a bound instance of the form is created using request.POST. If the submitted data is valid, it is processed and the user is re-directed to a "thanks" page.

• If the form has been submitted but is invalid, the bound form instance is passed on to the template.

Processing the data from a form

• What is cleaned_data? • For example, DateField normalizes input into

Python datetime.date object. Regardless of whether you pass it a string in the format '1994-07-15', a datetime.date object, or a number of other formats,DateField will always normalize it to a datetime.date object as long as it's valid.

Displaying a form using a template

• form.as_p, form.as_table, form.as_ul (list)

• Form.errors: Access the errors attribute to get a dictionary of error messages:

Customizing the form template

• {{ field.label }}

• {{ field.label_tag }}

• {{ field.value }}

• {{ field.html_name }}

• {{ field.help_text }}

• {{ field.errors }}

Looping over the form's fields

Form fields – core fields argument

• required

• label:

Form fields – core fields argument • initial:

• help_text:

• Error_messages:

Form fields – built in fields classes • BooleanField

• CharField

• ChoiceField

• TypedChoiceField

• DateField

• DateTimeField

• DecimalField

• EmailField

• FileField

• FilePathField

• FloatField

• ImageField

• IntegerField

• IPAddressField

• GenericIPAddressField

• MultipleChoiceField

• TypedMultipleChoiceField

• NullBooleanField

• RegexField

• SlugField

• TimeField

• URLField

ModelForms

• Make form directly from models

• Fields type conversion: see more at: https://docs.djangoproject.com/en/1.4/topics/forms/modelforms/#field-types

ModelForms • The save() method:

• creates and saves a database object from the data bound to the form.

• save() will raise a ValueError if the data in the form doesn't validate -- i.e., if form.errors evaluates to True.

• If you call save() with commit=False, then it will return an object that hasn't yet been saved to the database.

• you can invoke save_m2m() to save the many-to-many form data

ModelForms – customize

• Overriding the default field types or widgets:

Forms – Exercises

• Write 2 pages that have functions:

• Django Templates Exercise, when click on a name of an employee, this will link to the page of displaying details of this employee. At this page, you can edit the information and save to the database!, or at this page, if you want to delete this employee, you can press button delete. Be careful the integrity with other tables!.

• Creating new employee page and save to the database.

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

File Uploads and Generic View- reference • (1) File Uploads:

https://docs.djangoproject.com/en/1.4/topics/http/file-uploads/

• (2) Storage API: https://docs.djangoproject.com/en/1.4/ref/files/storage/

• (3) Managing Files: https://docs.djangoproject.com/en/1.4/topics/files/

• (4) Output PDF with Django: https://docs.djangoproject.com/en/1.4/howto/outputting-pdf/

• (5) Generic Views: https://docs.djangoproject.com/en/1.4/topics/class-based-views/ and: https://docs.djangoproject.com/en/1.4/ref/generic-views/

• (6) Built in Generic Views: https://docs.djangoproject.com/en/1.4/ref/class-based-views/

File Uploads and Generic View - Outcomes

• Know how to work with file upload

• Understand how generic view works

• Write a simple program to deal with file upload and generic views

File Uploads

• Conditions in templates to use:

• enctype="multipart/form-data“

• method was POST

Handling uploaded files

• read()

• multiple_chunks()

• chunks()

• name

• size

• Changing upload handlers: in settings.py: • FILE_UPLOAD_MAX_MEMORY_SIZE

• FILE_UPLOAD_TEMP_DIR

• FILE_UPLOAD_PERMISSIONS

• FILE_UPLOAD_HANDLERS

Storage class

• accessed_time(name)

• created_time(name)

• delete(name)

• exists(name)

• get_available_name(name)

• get_valid_name(name)

• listdir(path)

• modified_time(name)

• open(name, mode='rb')

• path(name)

• save(name, content)

• size(name)

• url(name)

Outputting PDF • Install ReportLab:

• Write your view

Generic Views

• Generic views:

• let you quickly provide common views of an object without actually needing to write any Python code.

• django.views.generic.simple • django.views.generic.simple.direct_to_template:

• django.views.generic.simple.redirect_to

Generic Views (cont.) • Other Generic views:

• Date-based generic views

• django.views.generic.date_based.archive_index

• django.views.generic.date_based.archive_year

• django.views.generic.date_based.archive_month

• django.views.generic.date_based.archive_week

• django.views.generic.date_based.archive_day

• django.views.generic.date_based.archive_today

• django.views.generic.date_based.object_detail

• List/detail generic views

• django.views.generic.list_detail.object_list

• django.views.generic.list_detail.object_detail

• Create/update/delete generic views

• django.views.generic.create_update.create_object

• django.views.generic.create_update.update_object

• django.views.generic.create_update.delete_object

Generic Views (cont.)

• list_detail.object_list e.g

• Other necessary fields:

• To build a list page of all publishers

• In the absence of an explicit template Django will infer one from the object's name. i.e. "books/publisher_list.html“

• Remember to enable in TEMPLATE_LOADERS in settings.py

• Other generic views should know: • Simple generic views

• View

• TemplateView

• RedirectView

• Detail views • DetailView

• List views • ListView

File Uploads and GV - Exercises

• In Edit and create new Employee, add or change avatar image Upload fields (remember to add fields in models.py)

• Write generic Views page for simple pages like: welcome page, Successful page,...

Contents

Part 4: Models

Part 5: QuerySets

Part 6: Admin Sites

Part 10: Forms

Part 13: Deployment

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