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

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

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)


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.
related.


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.
related.

• 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.djangoproje
ct.com/en/1.4/ref/model
s/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):
address = models.CharField(max_length=50)
website = models.URLField(blank= True,null=True)
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)
gender = models.CharField(max_length=1,choices=Gender_choise)
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)
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_CONT
EXT_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


• ModelAdmin.list_display

ModelAdmin.list_display_links
ModelAdmin.list_editable


• 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)


Django shortcut functions
• 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 (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.


• redirect(to[, permanent=False], *args, **kwargs):
• Returns an HttpResponseRedirect to the appropriate URL
for the arguments passed.


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


Variable
• Syntax: {{ variable }}

i = 1, j = 2
<p> This is line {{ i }}</p> <p> This is line 1</p>
<p> This is line {{ j }}</p> <p> This is line 3</p>

class book(models.Model):
title = models.CharField(max_length=50)
author = models.CharField(max_length=35)
obj = book(title = “My life”, author = “Unknow”)

<h3> {{ obj.title }} </h3> <h3> My life </h3>
<p> {{ obj.author }} </p> <p> Unknow </p>

obj can be a non-parametric function


Filters
• Use filters to modify variables for display

• Syntax: {{ variable | filter [| filter …] }}
value1 = “” value2 = [1, 4, 2, 6]
<p>{{ value1 | default: "nothing" }}</p> <p> nothing </p>

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

More:
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/


Tags
• Syntax:

• {% tag %}

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

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

list = [1, 2, 3, 4] display: List: 1 2 3 4
list = [] display: List is empty
• {# This is a comment #}


Tags: inheritance
• base.html

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

• template.html

{% 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: <b>Bold</b>

This will not be escaped: Bold

Block autoescape
{% autoescape on %} {% autoescape off %}
Example {{ obj }} Example {{ obj }}
{% endautoescape %} {% endautoescape %}
Example <b>Bold</b> Example Bold


Loading templates
setting.py template.html
TEMPLATE_DIR = (
<p> This is a book </p>
“mysite/app/template”,
<p> Title: {{ book.title }} </p>
“home/default”,
<p> Author: {{ book.author }}</p>
)

views.py
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: 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/modelfor
ms/


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


Looping over the form's fields

• {{ field.label }}
• {{ field.label_tag }}
• {{ field.value }}
• {{ field.html_name }}
• {{ field.help_text }}
• {{ field.errors }}


Form fields – core fields argument
• required

• label:


Form fields – core fields argument
• initial:

• help_text:

• Error_messages:


Form fields – built in fields classes
• BooleanField • IntegerField
• CharField
• IPAddressField
• ChoiceField
• GenericIPAddressField
• TypedChoiceField
• MultipleChoiceField
• DateField
• TypedMultipleChoiceFi
• DateTimeField
eld
• DecimalField
• EmailField
• NullBooleanField
• FileField • RegexField
• FilePathField • SlugField
• FloatField • TimeField
• ImageField • URLField


ModelForms
• Make form directly from models

• Fields type conversion: see more at:
https://docs.djangoproject.com/en/1.4/topics/forms/modelfo
rms/#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



• 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


Other topics - references
• (1) User authentication in Django:
https://docs.djangoproject.com/en/dev/topics/auth/
• (2) Testing Django Applications:
https://docs.djangoproject.com/en/dev/topics/testing/?from=o
lddocs
• (3) Sending Email:
https://docs.djangoproject.com/en/dev/topics/email/
• (4) Pagination:
https://docs.djangoproject.com/en/dev/topics/pagination/?fro
m=olddocs
• (5) Turn off debug modes:
http://djangobook.com/en/2.0/chapter12/


Other topics - Outcomes
• Understand clearly and apply these information in
your project, exercises.


User authentication
• The auth system consists of:
• Users
• Permissions: Binary (yes/no) flags designating whether a
user may perform a certain task.
• Groups: A generic way of applying labels and permissions
to more than one user.
• Installation, in settings.py:
• Put 'django.contrib.auth' and 'django.contrib.contenttypes'
in your INSTALLED_APPS setting.
• Run the command manage.py syncdb.


User authentication (cont.)
• Class models.User has fields:
• username
• Class models.User has methods:
• first_name
• is_anonymous()
• last_name
• is_authenticated()
• email
• get_full_name()
• password
• is_staff • set_password()
• is_active • check_password(raw_password)
• is_superuser • get_all_permissions(obj=None)
• last_login • email_user(subject, message, from
• date_joined _email=None)
• get_profile()
• Class models.UserManager has helper functions:
• create_user(username, email=None, password=None)
• make_random_password(length=10,allowed_chars='abcdefghjkmn
pqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789')


• Usage:
• creating users:

• changing password:

• creating superuser:


• Storing additional information about user:
• in modes.py:

User.profile = property(lambda u:
PubProfile.objects.get_or_create(user=u)[0]) # (Tips)
• in settings.py:


• How to log a user in:
• Authenticate() and login():

• logout():


• Limiting access – login_required decorator:
• decorators.login_required([redirect_field_name=REDI
RECT_FIELD_NAME,login_url=None])

• redirect_field_name by default is = “next”
• login_url by defaults is = settings.LOGIN_URL (in settings.py)

• And map with views:


• Writing login page:
• manually if you want like any other templates, and views
• Built-in views, the usage is like Generic Views:
• login(request[, template_name, redirect_field_name, authentic
ation_form])
• logout(request[, next_page, template_name, redirect_field_na
me])
• logout_then_login(request[, login_url])
• password_change(request[, template_name, post_change_redire
ct,password_change_form])
• password_change_done(request[, template_name])
• password_reset(request[, is_admin_site, template_name, email_
template_name,password_reset_form, token_generator, post_
reset_redirect, from_email])
• password_reset_done(request[, template_name])
• password_reset_confirm(request[, uidb36, token, template_name
, token_generator,set_password_form, post_reset_redirect])
• password_reset_complete(request[, template_name])
• redirect_to_login(next[, login_url, redirect_field_name])
• See more at (1)


• Built-in forms:
• class AdminPasswordChangeForm: A form used in the admin
interface to change a user's password.
• class AuthenticationForm: A form for logging a user in.
• class PasswordChangeForm: A form for allowing a user to
change their password.
• class PasswordResetForm: A form for generating and emailing
a one-time use link to reset a user's password.
• class SetPasswordForm: A form that lets a user change his/her
password without entering the old password.
• class UserChangeForm: A form used in the admin interface to
change a user's information and permissions.
• class UserCreationForm: A form for creating a new user.


Testing Django App.
• When you need testing:
• When you‟re writing new code, you can use tests to
validate your code works as expected.
• When you‟re refactoring or modifying old code, you can
use tests to ensure your changes haven‟t affected your
application‟s behavior unexpectedly.
• Writing tests: (write in tests.py)
• Unit tests (important!, mostly use)
• Doctests (just for simple tasks)


Testing Django App. (cont.)
• Running test:


• The test database:
• Tests that require a database (namely, model tests) will
not use your "real" (production) database. Separate,
blank databases are created for the tests.
• Regardless of whether the tests pass or fail, the test
databases are destroyed when all the tests have been
executed.
• Understanding test outputs:


• Test tools: if you want, look more info at (2):
• the test Client
• making request
• testing response
• Exceptions
• request factory
• URL configuration


Sending Email
• Testing on localhost:
• In settings.py:
• EMAIL_HOST = 'localhost'
• EMAIL_PORT = 1025
• Open a command-line: python -m smtpd -n -c
DebuggingServer localhost:1025
• Sending email with your Gmail account
• In settings.py:
• EMAIL_HOST = 'smtp.gmail.com'
• EMAIL_HOST_USER = 'abc@gmail.com'
• EMAIL_HOST_PASSWORD = 'yourpass'
• EMAIL_PORT = 587 # Check on the Internet if not successful
• EMAIL_USER_TLS = True # Gmail now accepts HTTPS only


Sending Email (cont.)
• in views.py:

• send_mail(subject, message, from_email, recipient_list, fail_silently=F
alse,auth_user=None, auth_password=None, connection=None)
• send_mass_mail(datatuple, fail_silently=False, auth_user=None,auth
_password=None, connection=None)
• mail_admins(subject, message, fail_silently=False, connection=None,
html_message=None)
• mail_managers(subject, message, fail_silently=False, connection=No
ne,html_message=None)


Sending Email (cont.)
• Prevent Header injection: - handling email form


Pagination
• In views.py:


Pagination (Cont.)
• in templates (html files)


Turn Debug mode off
• in settings.py, you set TEMPLATE_DEBUG and
DEBUG to False
• write 404.html


Turn Debug mode off (cont.)
• And write 500.html template

• Setting up Error alert:


Other topics - Exercise
• Create a page for user authentication, when user
authenticated, they will see
“authenticated_page.html” that you can write
anything that you want.
• Write unit test for some functions in Query Set's
exercise
• In the Django Templates' exercise, add function
send to my email button to send result of
searching employee given name or ssn or bdate
• If the result in search employee is above 5, use
pagination to cut off the display to another pages.


Contents
Part 4: Models
Part 5: QuerySets
Part 6: Admin Sites
Part 10: Forms
Part 13: Deployment


Deployment - References
• (1) How to use Django with Apache and mod_wsgi
https://docs.djangoproject.com/en/1.3/howto/deployment/mo
dwsgi/
• (2) Notes on using pip and virtualenv with Django
http://www.saltycrane.com/blog/2009/05/notes-using-pip-
and-virtualenv-django/


PART 13 - DEPLOYMENT
Time to attract people to your website


Outline
• Setup environment
• Use Virtualenv
• Deploy w/ Apache2 and Mod_WSGI
• Serve static files


SETUP ENVIRONMENT


Prerequisites
• Ubuntu (10.4 or newer) server or desktop
• Apache2
• Virtualenv
• Django 1.x and other libs on Virtualenv


Installing Apache2
• Update the source list for newest version
> sudo apt-get update
• Install Apache2 and mod_wsgi
> sudo apt-get install apache2 libapache2-mod-
wsgi


Installing Virtualenv
• Install python setup tools and pip
> sudo apt-get install python-setuptools python-
dev build-essential
> sudo apt-get install python-pip
• Install virtualenv
> pip install virtualenv


USE VIRTUALENV


What is Virtualenv?
• An isolated Python environment. Allows you to
control which packages are used on a particular
project by cloning your main Python.
• For example, you can run both Django 1.1 and
Django 1.4 project on the same server with
Virtualenv.


Create a virtual environment
• The straight way
> virtualenv ~/.virtualenv/myenv
• If you want to use different Python version
> virtualenv --python=/usr/bin/python2.5
~/.virtualenv/myenv

Note: ~/.virtualenv/myenv is just an example path,
in fact you can create the environment at
anywhere.


Use it!
• Activate the virtual enviroment
> source ~/.virtualenv/myenv/bin/activate
• Deactivate
(myenv)> deactivate
• Install Django package
(myenv)> pip install django
• Install MySQL-Python
(myenv)> pip install mysql-python


DEPLOY W/ APACHE2 AND
MOD_WSGI


Components

links to
Apache Script WSGI Script

links to

Django Project
Directory


Apache script (Virtualhost)
• Copy the following script into /etc/apache2/sites-
available/myproject
<VirtualHost *:80>
ServerName mysite.com, www.mysite.com

CustomLog /var/logs/myproject-access_log common
ErrorLog /var/logs/myproject-error_log

Alias /home/user1/www/myproject/media
<Directory /home/user1/www/myproject/static>
Order allow,deny
Options Indexes
Allow from all
</Directory>

WSGIScriptAlias / /home/user1/www/myproject/myproject.wsgi
</VirtualHost>


WSGI script
• Copy this into
home/user1/www/myproject/myproject.wsgi
import os
import sys

root_path = '/home/user1/www'
project_path = '/home/user1/www/myproject'
if root_path not in sys.path:
sys.path.append(root_path)
if project_path not in sys.path:
sys.path.append(project_path)

os.environ['DJANGO_SETTINGS_MODULE'] = „myproject.settings'

import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()


Enable site
• Enable Apache script
> a2ensite myproject
• Restart Apache server
> sudo service apache2 restart


Deployment - Outcome
• In Apache script, you have seen the line:
ServerName mysite.com, www.mysite.com

• To access myproject.com site, in practice you need
to buy a domain (myproject.com) and append
DNS record to point to the server IP. It is beyond
this course.
• You will test the deployment outcome in local
server by configuring the host file. This is a very
useful tip especially when you deploy the project
before buying a domain.
• Tip: it’s the same technique used to by-pass
Facebook blocking.


Configure your host file
• Open the host file with nano
> sudo nano /etc/hosts
• Append 2 lines
127.0.0.1 myproject.com
127.0.0.1 www.myproject.com
• Press Ctrl+X and prompt Y to save the file
• Finally, open the browser at www.myproject.com.


Deployment - Exercises
• Deploy your Django project with nginx (a different
web server).


Final Projects
• You can choose any topics from your own such as
a social network or e-commerce websites... That
must be contains almost all features or more that
you learn from our course.
• Or you can complete all Exercises in this course
about Employee Project management and add
another functions if you don‟t have much time to
do.
• If you do in groups, remember to use SVN for
easy to maintain your codes.


Django Dev. Determine the functions
of your website

Process Design your database in ERD
and implements in models.py
• You can refer to this
process to do your Determine how many pages you

final project. needed and url for each page,
then implements in urls.py

Design your base.html layout by
hand or by Photoshop

Implement your functions in
views.py, forms.py, admins.py Display your views to django
templates (.html) file

Complete your sites by adding css,
js, and other stuff

Run on localhost and testing, and
then deploy in a server

Python/Django Training

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