==== Create a project ====
<code bash>
django-admin startproject mysite
python manage.py migrate
</code>

Create a super user account, which can login via http://localhost:8000/admin
<code bash>
python manage.py createsuperuser
</code>

==== Launch the server ====
<code lang=bash>
python manage.py runserver
</code>

==== Create a app inside a project ====
Everything are apps. Each app has it's own subfolder. To create a app sceleton run
<code lang=bash>
python manage.py startapp polls
</code>

==== Register URL ====
In the polls/urls.py file include the following code:
<code python polls/urls.py>
polls/urls.py¶

from django.urls import path

from . import views

urlpatterns = [
    # ex: /polls/
    path('', views.index, name='index'),
    # ex: /polls/5/
    path('<int:question_id>/', views.detail, name='detail'),
    # ex: /polls/5/results/
    path('<int:question_id>/results/', views.results, name='results'),
    # ex: /polls/5/vote/
    path('<int:question_id>/vote/', views.vote, name='vote'),
]
</code>

The corresponding view looks like this. The name correspond with the method name of views.py.
<code python polls/views.py>
from django.shortcuts import render
from django.http import HttpResponse


def index(request):
    return HttpResponse("Hello, world. You're at the polls index.")


def detail(request, question_id):
    return HttpResponse("You're looking at question %s." % question_id)

def results(request, question_id):
    response = "You're looking at the results of question %s."
    return HttpResponse(response % question_id)

def vote(request, question_id):
    return HttpResponse("You're voting on question %s." % question_id)
</code>

Now we need to add this url to our project:

<code python mysite/urls.py>
from django.contrib import admin
from django.urls import include, path

urlpatterns = [
    path('polls/', include('polls.urls')),
    path('admin/', admin.site.urls),
]
</code>

==== Templates ====
Templates are in the subfolder of the app. e.g. `mysite/polls/templates/*`
<code html polls/templates/polls/index.html>
{% if latest_question_list %}
    <ul>
    {% for question in latest_question_list %}
        <li><a href="/polls/{{ question.id }}/">{{ question.question_text }}</a></li>
    {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}
</code>

To render such a templates you need to do response the corresponding HttpResponse:
<code python polls/view.py>
  latest_question_list = Question.objects.order_by('-pub_date')[:5]
    template = loader.get_template('polls/index.html')
    context = {
        'latest_question_list': latest_question_list,
    }
    return HttpResponse(template.render(context, request))
</code>

or in short
<code python polls/view.py>
from django.shortcuts import render

def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    context = {'latest_question_list': latest_question_list}
    return render(request, 'polls/index.html', context)
</code>


==== Namespace url patterns ====
Define the namespace by adding `app_name = <namespace>` inside of urls.py.
<code python polls/urls.py>
app_name = 'polls'
urlpatterns = [
    # ex: /polls/
    path('<int:question_id>/', views.detail, name ='detail');
]
</code>
Then you need to specfiy the namespace in `{% url %}` of the template like this
<code html polls/templates/polls/detail.html>
        <li><a href="{% url 'polls:detail' question.id %}">{{ question.question_text }}</a></li>
</code>

==== Static files ====
Static files can be placed in the `static/` folder of each app.
Then refere to them inside the template like:
<code html polls/templates/polls/index.html>
{% load  static %}
<link rel="stylesheet" type="text/css" href="{% static 'polls/style.css' %}">
</code>

Run this command to store static files in proper folder:
<code bash>
python manage.py collectstatic
</code>
==== django_tables2 ====
=== Mixedin ===

<code python>
class UsefulMixin(tables.Table):
    age = AgeColumn()
    options = tables.Column(empty_values=())

    def render_options(self):
        return format_html('<button>DELETE</button>')
#    age = tables.Column()

class InstanceTable(UsefulMixin, tables.Table):
    age = AgeColumn()
    opt = tables.LinkColumn('delete_instance', args=[A('pk')], text='delete')
    class Meta:
        model = Instance
        template_name = 'django_tables2/bootstrap.html'

</code>

===  Custom tables.Column ===
<code python>
class AgeColumn(tables.Column):
    def render(self, record):
        diff = record.age()
        color = ''
        if (diff.seconds > 60 * 60 ):
            color = 'red'
        else:
            color = 'green'
        return format_html('<span style="color:{}">{}</span>',color, diff)


class InstanceTable(tables.Table):
    age = AgeColumn()
    opt = tables.LinkColumn('delete_instance', args=[A('pk')], text='delete')
    class Meta:
        model = Instance
        template_name = 'django_tables2/bootstrap.html'
</code>

To make links of a value https://django-tables2.readthedocs.io/en/latest/pages/api-reference.html?highlight=LinkColumn#django_tables2.columns.LinkColumn
==== Update database ====
Change the model file accordingly. [[https://docs.djangoproject.com/en/2.1/ref/django-admin/#makemigrations|doc:makemigrations]]
<code bash>
python manage.py makemigrations
python manage.py migrate
</code>

==== Bootstrap ====
https://www.w3schools.com/bootstrap/default.asp


==== Django Rest Framework ====
https://www.django-rest-framework.org/tutorial/quickstart/