Django - vimlesh-verma16/Notes GitHub Wiki

Repo link https://github.com/Pierian-Data?tab=repositories

Repo link:: https://github.com/codingforentrepreneurs/eCommerce

Date : March 4 2025

Create Virtual environment:

python -m venv env  
env\Scripts\activate
pip freeze > requirements.txt
pip3 install -r requirements.txt

Conda Specific commands

conda create --name env_name python=3.6 [for specific version]
python -m django --version
conda create --name myDjangoEnv django
conda info --envs
conda env list (conda activate envname)
conda remove --name ecommerce --all

Django Commands flow

django-admin startproject first_project 
python manage.py runserver
python manage.py startapp first_app

ADD first_app in INSTALLED_APPS [settings.py]

full Flow Client → Django URLs → Middleware (pre-processing) → View → Middleware (post-processing) → Response to Client

The name="index" Parameter This assigns a name (index) to this URL pattern, making it easier to reference in templates and redirects: < href="{% url 'index' %}">Home

If the URL changes, you only need to update urlpatterns without changing every reference in your templates.

Templates and Static files (Join Base dir with static and template)

BASE_DIR = Path(file).resolve().parent.parent
TEMPLATE_DIR=os.path.join(BASE_DIR,"templates")
STATIC_DIR=os.path.join(BASE_DIR,"static")

Now add TEMPLATE_DIR in Dirs

Models (Django level two )

CRUD Operations: Create -- POST Retrieve/List/Search -- GET Update -- PUT/Patch/POST Delete -- Delete

Model class should always be named as: Product(ProductCategory) and not Products

python manage.py makemigrations  
python manage.py migrate

Now go to admin and register your models admin.site.register(Webpage)

python manage.py shell (to test our models)

from first_app.models import Topic print(Topic.objects.all()) <QuerySet []> t= Topic(top_name = "Social Network") t.save() print(Topic.objects.all()) <QuerySet [<Topic: Social Network>]> quit()

python manage.py createsuperuser
vimlesh
vimmu1998

test
test

Now go to admin
http://127.0.0.1:8000/admin

Flow Model -> Template -> View
first grab all the data view.py file in index function and now inject it to template and then set in url.py

Django Level Three (Forms)

When form method is POST use

<form method = "POST"> {% csrf_token %}
    <input  type = "text" class = "form-control" placeholder="Name" name = "FullName">
    <button type = "Submit" class = "btn btn-default"> Submit</button> 
</form>

This is how we can get content from frontend

<input  type = "text" class = "form-control" placeholder="Name" name = "fullname">
"fullname" is dictionary.  
if request.method == "POST":
    print(request.POST)
    print(request.POST.get("fullname"))

built in django form flow

Now Instead of using the entire Hardcoded Form, we can use django built in form. 
1. 
form.py file. 
class ContactForm(forms.Form):
    fullname = forms.CharField(
        widget=forms.TextInput(
            attrs={"class": "form-control", "placeholder": "Your Full Name"}
        )
    )

2. 
from .form import ContactForm 
contact_form = ContactForm()
context = {
    "title": "Contact Page -> from view.html",
    "content": "Welcome to contact page",
    "form": contact_form,
}
if request.method == "POST":
    # print(request.POST)
    print(request.POST.get("fullname"))

3.     
<form method = "POST"> {% csrf_token %}
{{ form }}
<button type = "Submit" class = "btn btn-default"> Submit</button> 
</form>

4. Now you need to modify to get clean data
contact_form = ContactForm(request.POST or None)

if contact_form.is_valid():
    print(contact_form.cleaned_data)
{'fullname': 'vimmu', 'email': '[email protected]', 'content': 'hello 3nd hit'}

5. validation check to raise error in frontend
    def clean_email(self):
        email = self.cleaned_data.get("email")
        if "gmail.com" not in email:
            raise forms.ValidationError("Email has to be gmail.com")
        return email

def clean(self): (method is called by itself) all_cleaned_data = super().clean()

Django Level 4 (Templates inheritance)

app_name = 'basic_app' urlpatterns = [ path('relative/',views.relative ,name='relative'), path('other/',views.other,name='other') ]

template tagging ->

< href="{% url 'basic_app:other' %}"> relative path

info about above code : basic app is coming from app_name and other is coming from name

'basic_app:other' dont give space here or you will get error

< href="{% url 'admin:index' %}"> LINK TO ADMIN

this will not work unless you migrate

filter for django templates {{ username|default:"Guest" }} {{ "This is a long sentence."|truncatewords:3 }} {{ vimlesh| upper }}

Django Level 5 (UserAuthentication) Study again

pip install bcrypt pip install django[argon2]

in login

check whether the user is authicated or not

Add this arrays in settings.py

PASSWORD_HASHERS = [
    "django.contrib.auth.hashers.PBKDF2PasswordHasher",
    "django.contrib.auth.hashers.PBKDF2SHA1PasswordHasher",
    "django.contrib.auth.hashers.Argon2PasswordHasher",
    "django.contrib.auth.hashers.BCryptSHA256PasswordHasher",
    "django.contrib.auth.hashers.ScryptPasswordHasher",
]
AUTH_PASSWORD_VALIDATORS = [
    {
        "NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator",
    },
    {
        "NAME": "django.contrib.auth.password_validation.MinimumLengthValidator",
        "OPTIONS": {"min_length": 9},
    },
    {
        "NAME": "django.contrib.auth.password_validation.CommonPasswordValidator",
    },
    {
        "NAME": "django.contrib.auth.password_validation.NumericPasswordValidator",
    },
]

Now create a User:Model

Now register the model like this in admin.py of app

from basic_app.models import UserProfileInfo
admin.site.register(UserProfileInfo)

Create a function in view.py file to handle request
Create a login.html and create a user_login fucntion in views.py
Create a user_login fun in view.py and do some code in main html file to show whether the user is loggin in or logged out

class Meta: flow models -> form -> admin

different ways to use authentication

:: BACKEND

    if form.is_valid():
        print("üser logged in :", request.user.is_authenticated)
        print(form.cleaned_data)  # cleaned_data is a dictionary
        username = form.cleaned_data.get("username")
        password = form.cleaned_data.get("password")
        user = authenticate(request, username=username, password=password)
        if user is not None:
            login(request, user)


def home_page(request):
    context = {
        "title": "Home Page -> from home.html",
        "content": "Welcome to home page",
    }
    if request.user.is_authenticated:
        context["premium_content"] = "YEAHhhhhhhh!"
    return render(request, "home.html", context)

::FRONTEND

        {% if premium_content %} 
        {% comment %} {% if request.user.is_authenticated %}  {% endcomment %}
            <div class='text-center'> 
                <h1> Premium Content </h1>
                <p>{{ premium_content }}</p> 
            </div>
        {% endif %}


# cleaned data is dictionary
    def clean(self):
        data = self.cleaned_data
        password = self.cleaned_data.get("password")
        password2 = self.cleaned_data.get("password2")


Creating a new user in register page
User = get_user_model()

    username = form.cleaned_data.get("username")
    email = form.cleaned_data.get("email")
    password = form.cleaned_data.get("password")
    User.objects.create_user(username, email, password)

Static files

Always add css file after bootstrap css or it will overwrite