mp5maker/trydjango

Try Django

All thanks to Coding Entrepreneurs

Operating System

Working in Linux Ubuntu 18.04

Installation

    sudo apt-get install pip
    sudo apt-get install nodejs

    pip install environ
    pip install virtualenvwrapper
    pip install Django==1.11.16

    export WORKON_HOME=~/Envs
    mkdir -p $WORKON_HOME
    source /usr/local/bin/virtualenvwrapper.sh
    source ~/.bashrc
    mkvirtualenv djangoconcepts

Virtual Environment Commands

1. mkvirtualenv [name]
2. rmvirtualenv [name]
3. workon [name]
4. deactivate

Django Admin Command

django-admin startproject [name]

Management Commands

• python manage.py migrate
• python manage.py runserver
• python manage.py shell_plus
• python manage.py shell
• python manage.py startapp angular
• python manage.py createsuperuser
• python manage.py makemigration [name]

Folder Setups [In my current folder]

    mkdir src
    cd src
    django-admin startproject trydjango .

Settings [src/django/settings.py]

1) Where my manage.py file is ?

    print BASE_DIR
    In my case,
    /home/photon/Downloads/trydjango/src

2) What is installed app ?

• All the apps must be entered here INSTALLED_APPS

3) What is URL CONF ?

• Url configuration manages all the routes

4) Where do we store the js, css, html?

• STATIC_URL

Create Superuser

• Create superuser

    python manage.py createsuperuser

Create New App

• Create new app

    python manage.py startapp products

Create Model [models.py] and Make Migrations

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models

# Create your models here.
class Product(models.Model):
    title       = models.TextField() 
    description = models.TextField()
    price       = models.TextField()
    summary     = models.TextField(default="Write Meaningful Description")

    python manage.py makemigrations
    python manage.py migrate

Register in Admin [admin.py]

    admin.site.register(*model-name*) 

Python Shell

    python manage.py shell

    from products.models import Product
    
    Read,
    result = Product.objects.all()
    str(result.query)
    print result

    Create,
    Product.objects.create(title="String", description="Ernie Balls", price="8.99", summary="")

Updating the Model

• Updating the previous model with new fields with default value to new fields

    class Product(models.Model):
        title       = models.CharField(max_length=120) # max_length is required
        description = models.TextField(blank=True, null=True)
        price       = models.DecimalField(decimal_places=2, max_digits=1000)
        summary     = models.TextField(default="Write Meaningful Description")
        ## Added After two products were added, featured was added
        featured    = models.BooleanField() # null=True, default=True

    python manage.py makemigrations
    
    Choose > Provide a one-off default now
    Press 1
    Type True
    
    python manage.py migrate

Creating a View [views.py]

    from django.http import HttpResponse

    class Home(*args, **kwargs):
        return Response("<h1> Hello World </h1>")

Create a url for the view trydjango[urls.py]

    from django.conf.urls import url
    from django.contrib import admin
    from products.views import home

    urlpatterns = [
        url(r'^admin/', admin.site.urls),
        url(r'^', home, name="home"),
    ]

Print arguments and keyword arguments[views.py]

    class Home(*args, **kwargs):
        print(args, kwargs) # We can see in the server 
        return Response("<h1> Hello World </h1>")

    (<WSGIRequest: GET '/'>,), {})

Therefore we can write,

    class Home(request, *args, **kwargs):
        print(args, kwargs) # We can see in the server 
        ## We will see the request
        return Response("<h1> Hello World </h1>")

What can request do ?

• We can see the which user sent the request, authentication,login helps

        class Home(request, *args, **kwargs):
        # print(args, kwargs) # We can see in the server 
        # print(request.user) # Requested user info
        return Response("<h1> Hello World </h1>")

Template (views.py)

from django.shortcuts import render

# Create your views here.
def home(request, *args, **kwargs): 
    return render(request, "home.html", {})

Templates in src folder

    mkdir templates

Setup Django where templates are (settings.py)

    TEMPLATES = [
        {
            'DIRS': [os.path.join(BASE_DIR, 'templates')],
            ...
        }
    ]

Using Jinja Templates

    [Jinja Template Inheritance]
    {% extends 'base.html'}
    {% block content %}
    {% endblock %}

    [Jinja Template Include]
    {% include 'layouts/navbar.html' %}

    [Jinja Template for Loop]
    {% for item in list %}
    {% endfor %}
    We can use *forloop.counter* to count the loop

    [Jinja Template Conditions]
    {% if <<condition>> %}
    {% elif <<condition>> %}
    {% else %}
    {% endif %}

Template Tag Filters

• {{ variable | upper }}
• {{ variable | add }}
• {{ variable | slugify }}
• {{ variable | capfirst }}
• {{ variable | safe }}
• {{ variable | striptags }}

Access the Data through Shell

<< Get the Query Set >>

    from products.models import Product
    obj = Product.objects.all()
    str(obj.query)
    print obj

<< Get all the attributes, mthod of a certain object >>

    from products.models import Product
    obj = Product.objects.get(pk=1)
    dir(obj)
    obj.title

Render Data from the Database

1. Write the naming convention of the functions in the view in lowercase
2. Write the name convention of the functions in the model in uppercase

views.py

    from .models import Product 
    def product_detail(request, *args, **kwargs):
    obj = Product.objects.get(pk=1)
    context = {
        "title": obj.title,
        "description": obj.description
    }
    return render(request, 'product/detail.html', context)

product/detail.html

{% extends 'base.html' %}

{% block content %}
<div class="container">
    <div class="row">
        <div class="col">
            <h1>Items</h1>
            <div class="information">
                <ul>
                    <li>
                        <span>
                            {{ title }}
                        </span>
                        {% if description != Null and description != '' %}
                        <span>
                            {{ description}}
                        </span>
                        {% else %}
                        <span>
                            Coming Soon
                        </span>
                        {% endif %}
                    </li>
                </ul>
            </div>
        </div>
    </div>
</div>
{% endblock %}

views.py [Improved]

def product_detail(request, *args, **kwargs):
    obj = Product.objects.get(pk=1)
    context = {
        "obj": obj
    }
    return render(request, 'product/detail.html', context)

Changing the location of the template

Inside the Product app,

    mkdir templates
    cd templates 
    mkdir products
    touch detail.html

Intentionally making mistake in views.py

    return render(request, 'productss/detail.html', context)

Checking the Template loader post mortem

django.template.loaders.filesystem.Loader: /home/photon/Downloads/trydjango/src/templates/productss/detail.html 

Comes from the settings 'DIRS': [os.path.join(BASE_DIR, 'templates')]

django.template.loaders.app_directories.Loader: /home/photon/Downloads/trydjango/src/products/templates/productss/detail.html

Comes from the products app

django.template.loaders.app_directories.Loader: /home/photon/.virtualenvs/trydjango/local/lib/python2.7/site-packages/django/contrib/admin/templates/productss/detail.html

*Comes from the contrib/admin

django.template.loaders.app_directories.Loader: /home/photon/.virtualenvs/trydjango/local/lib/python2.7/site-packages/django/contrib/auth/templates/productss/detail.html

*Comes from the contrib/auth

Django Forms

touch forms.py

forms.py

from django import forms
from .models import Product

class ProductForm(forms.ModelForm):
    class Meta:
        model = Product
        fields = [
            'title',
            'description',
            'price'
        ]

views.py

from .forms import ProductForm
def product_form_view(request, *args, **kwargs):
    form = ProductForm(requestPost or None)
    if form.is_valid():
        form.save()
        form = ProductForm()
    context = {
        "form": form
    }
    return render(request, 'product_form_view.html', context)

products/product_form_view.html

{% extends 'base.html' %}

{% block content %}
<form method="POST">
    {% csrf_token %}
    {{ form.as_p }}
    <input type="submit" value="Save"/>
</form>
{% endblock %}

[trydjango] urls.py

url(r'^product/create/', product_form_view, name="product_form_view")

Creating Raw Django Form

views.py

def product_form_raw(request, *args, **kwargs):
    my_form = ProductRawForm()
    if request.method == "POST":
        my_form = ProductRawForm(request.POST)
        if my_form.is_valid():
            print my_form.cleaned_data 
            Product.objects.create(**my_form.cleaned_data)
        else:
            print my_form.errors
    else:
        my_form = ProductRawForm(None)
    context = {
        "form": my_form
    }
    return render(request, 'products/product_form_raw.html', context)

forms.py

class ProductRawForm(forms.Form):
    title = forms.CharField()
    description = forms.CharField()
    price = forms.DecimalField()
    summary = forms.CharField()
    featured = forms.BooleanField()

[trydjango] urls.py

    url(r'^product/rawcreate/', product_form_raw, name="product_form_raw")

Form Widgets

forms.py

    class ProductRawForm(forms.Form):
    title = forms.CharField(
                        label='', 
                        widget=forms.TextInput(
                            attrs= {
                                "placeholder": "Your title"
                            }
                        )
                    )
    description = forms.CharField(
                        required=False, 
                        widget=forms.Textarea(
                            attrs={
                                "class": "new-class-name two",
                                "id": "my-id-for-text-area",
                                "rows": 10,
                                "cols": 20
                            }
                        )
                    )
    price = forms.DecimalField(initial=12.99)
    summary = forms.CharField()
    featured = forms.BooleanField()

Form Validation Methods

class ProductForm(forms.ModelForm):
title = forms.CharField(
    label='',
    widget=forms.TextInput(
        attrs={
            "placeholder": "Your Title"
        }
    )
)
class Meta:
    model = Product
    fields = [
        'title',
        'description',
        'price',
        'summary',
        'featured',
    ]
def clean_title(self, *args, **kwargs):
    title = self.cleaned_data.get("title")
    if not "Photon" in title:
        raise forms.ValidationError("This is not a valid title")
    return title

def clean_price(self, *args, **kwargs):
    price = self.cleaned_data.get("price")
    if price < 0:
        raise forms.ValidationError("This is not a valid number")
    return price

Set Initial Data to the form

views.py

def product_initial_data(request, *args, **kwargs):
    initial_data = {
        "title": "Initial Data"
    }
    obj = Product.objects.get(pk=1)
    form = ProductForm(request.POST or None, initial=initial_data, instance=obj)
    if form.is_valid():
        form.save()
    context = {
        "form": form
    }
    return render(request, 'products/product_initial_data.html', context)

Dynamic URL Routing

urls.py

    url(r'^product/dynamic-lookup/(?P<product_id>[0-9]+)/', dynamic_lookup_view, name="dynamic_look_view"),

views.py

    def dynamic_lookup_view(request, product_id):
        obj = Product.objects.get(id=product_id)
        context = {
            "obj": obj
        }
        return render(request, "products/dynamic_lookup.html", context)

Handle the Page that doesn't exist

views.py

from django.shortcuts import render, get_object_or_404, Http404

def dynamic_lookup_view(request, product_id):
    obj = get_object_or_404(Product, id=product_id)
    # try:
    #     obj = Product.objects.get(id=product_id)
    # except Product.DoesNotExist:
    #     raise Http404
    context = {
        "obj": obj
    }
    return render(request, "products/dynamic_lookup.html", context)

Delete a object in the database

views.py

from django.shortcuts import redirect, get_object_or_404

def product_delete_view(request, product_id, *args, **kwargs):
    obj = get_object_or_404(Product, id=product_id)
    if request.method == "POST":
        obj.delete()
        return redirect("home/")
    context = {
        "obj": obj
    }
    return render(request, "products/product_delete.html", context)

urls.py

url(r'^product/delete/(?P<product_id>[0-9]+)/', product_delete_view, name="product_delete_view")

products/product_delete.html

{% extends 'base.html' %}

{% block content %}
<form action="." method="POST">
    {% csrf_token %}
    <h1> Do you want to delete the product {{ obj.title }}</h1>
    <p>
        <input type="submit" value="Yes"/>
        <a href="../">Cancel</a>
    </p>
</form>
{% endblock %}

Getting list of all the objects from the model

     from products.models import Product
     Product._meta.get_fields()

views.py

    def product_list_view(request, *args, **kwargs):
    queryset = Product.objects.all()
    context = {
        "products": queryset
    }
    return render(request, "products/product_list.html", context)

urls.py

     url(r'^product/product-list/', product_list_view, name="product_list_view")

model.py

class Product(models.Model):
    title       = models.CharField(max_length=120) # max_length is required
    description = models.TextField(blank=True, null=True)
    price       = models.DecimalField(decimal_places=2, max_digits=1000)
    summary     = models.TextField(default="Write Meaningful Description")
    ## Added After two products were added, featured was added
    featured    = models.BooleanField() # null=True, default=True

    ## Get Absolute Url using the string substitution
    def get_absolute_url(self):
        return "/product/dynamic-lookup/{self.id}/"

/products/product_list.html

{% extends 'base.html' %}
{% block content %}
<div class="container">
    <div class="row">
        <div class="col">
            <div class="card">
                {% for product in products %}
                <div class="card-content">
                    <div class="card-title">
                        <h1>
                            {{ product.title }}
                        </h1>
                    </div>
                    <div class="card-body">
                        <div class="description">
                            <div>
                                <p>
                                    {{ product.description }}
                                </p>
                            </div>
                            <div>
                                <p>
                                    {{ product.summary }}
                                </p>
                            </div>
                        </div>
                    </div>
                    <div class="card-footer">
                        <p>
                            <span>
                                Price: 
                            </span>
                            <span>
                                <em>
                                    {{ product.price }}
                                </em>
                            </span>
                        </p>
                        <p>
                            <span>
                                Details Link: 
                            </span>
                            <span>
                                <em>
                                    <a href = "{{ product.get_absolute_url }}">
                                        {{ product.title }}
                                    </a>
                                </em>
                            </span>
                        </p>
                    </div>
                </div>
                {% endfor %}
            </div>
        </div>
    </div>
</div>
{% endblock %}

Absolute Urls Generating from Django

models.py

## Get Absolute Url using the string substitution
def get_absolute_url(self):
    return f"/product/dynamic-lookup/{self.id}"

Better way to do it

 ## Uses the name of the urls
    def get_absolute_url(self):
        return reverse("dynamic_lookup_view", kwargs={"product_id": self.id})

Taking the urls to the app modules

trydjango urls.py

 url(r'^products/', include('products.urls'))

products urls.py

from django.conf.urls import url

from .views import (
    home, contact,
    about, product_detail,
    product_form_view,
    product_form_raw, product_initial_data,
    dynamic_lookup_view, product_delete_view,
    product_list_view
)

urlpatterns = [
    url(r'^home/', home, name="home"),
    url(r'^contact/', contact, name="contact"),
    url(r'^about/', about, name="about"),
    url(r'^product/detail/', product_detail, name="product_detail"),
    url(r'^product/create/', product_form_view, name="product_form_view"),
    url(r'^product/rawcreate/', product_form_raw, name="product_form_raw"),
    url(r'^product/initialdata/', product_initial_data, name="product_initial_data"),
    url(r'^product/dynamic-lookup/(?P<product_id>[0-9]+)/', dynamic_lookup_view, name="dynamic_lookup_view"),
    url(r'^product/delete/(?P<product_id>[0-9]+)/', product_delete_view, name="product_delete_view"),
    url(r'^product/product-list/', product_list_view, name="product_list_view")
]

Namespacing the urls

products.urls.py

# This namespaces the url
app_name = "products"

products.models.py

    def get_absolute_url(self):
        # return f"/product/dynamic-lookup/{self.id}" # Better Way to url
        
        # This is going to use the name of the url
        return reverse("products:dynamic_lookup_view", kwargs={"product_id": self.id})

Products related links are in products app and home, about, contact are in pages app from now on

• Simple Task: **Organize the contact, home, about ** to a app called pages

Create a Blog App

All the methods are like previous ones

models.py

from django.db import models

# Create your models here.
class Article(models.Model):
    title = models.CharField(max_length=120)
    content = models.TextField()
    active = models.BooleanField(default=True)

For Class Based Views

views.py

from django.views.generic import (
    CreateView,
    DetailView,
    ListView,
    UpdateView,
    ListView,
    DeleteView
)
from .models import Article

class ArticleListView(ListView):
    template_name = 'articles/article_list.html'
    queryset = Article.objects.all() 

forms.py

from .models import Article
from django.forms import ModelForm

class ArticleForm(ModelForm):
    class Meta:
        model = Article
        fields = [
            'title',
            'content',
            'active'
        ]

urls.py

from django.conf.urls import url
from .views import ArticleListView

urlpatterns = [
    url(r'^article-list/', ArticleListView.as_view(), name="article-list-view")
]

html

{% extends 'base.html' %}

{% block content %}
<div class="container">
    <div class="row">
        <div class="col">
            {% for instance in object_list %}
            <div class="card">
                <div class="card-content">
                    <div class="card-header">
                        <p>
                            <strong>
                                {{ forloop.counter }} - {{ instance.title }}
                            </strong>
                        </p>
                    </div>
                    <div class="card-body">
                        <p>
                            <small>
                                {{ instance.content }}
                            </small>
                        </p>
                    </div>
                    <div class="card-footer">
                        <p>
                            <em>
                                <a href="">
                                    {{ instance.title }}
                                </a>
                            </em>
                        </p>
                    </div>
                </div>
            </div>
            {% endfor %}
        </div>
    </div>
</div>
{% endblock %}

Check the Blog App

More Concepts Based on Views

In concept app