01 Django Introduction

Step 1: Install Django and Set Up Virtual Environment¶

Create a virtual environment to isolate your project dependencies:

virtualenv venv
source venv/bin/activate  # On Windows use `venv\Scripts\activate`
deactivate # 退出虚拟环境

Install Django in the virtual environment:
```
pip install django
```

Step 2: Create a Django Project¶

Create a new Django project:
```
django-admin startproject recsys
```
Navigate into the project directory:
```
cd recsys
```

Your project structure will look like this:

recsys/
    manage.py
    recsys/
        __init__.py
        settings.py
        urls.py
        asgi.py
        wsgi.py

Step 3: Start the Local Development Server¶

You can start your Django development server to test if everything is working:

python manage.py runserver

Visit http://127.0.0.1:8000/ in your browser to verify the server is running.

Step 4: Create a Django App¶

Create a new app within your project:
```
python manage.py startapp reviewmaster
```

Your app structure will look like this:

reviewmaster/
    __init__.py
    admin.py
    apps.py
    migrations/
        __init__.py
    models.py
    tests.py
    views.py

Step 5: Add the App to Your Project¶

In recsys/settings.py, add the new app to the INSTALLED_APPS section:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'reviewmaster.apps.ReviewmasterConfig',
]

Step 6: Define Models for the App¶

In reviewmaster/models.py, define the models for User, Business, and Review:

from django.db import models

class User(models.Model):
    name = models.CharField(max_length=200)

    def __str__(self):
        return self.name

class Business(models.Model):
    name = models.CharField(max_length=200)
    city = models.CharField(max_length=200)
    users = models.ManyToManyField(User, through='Review')

    def __str__(self):
        return self.name

class Review(models.Model):
    RATING_STARS = [
        (1, 'One Star'),
        (2, 'Two Star'),
        (3, 'Three Star'),
        (4, 'Four Star'),
        (5, 'Five Star'),
    ]
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    business = models.ForeignKey(Business, on_delete=models.CASCADE)
    rating = models.IntegerField(choices=RATING_STARS)

    def __str__(self):
        return f'{self.user} rates {self.business} at {self.rating} star.'

Step 7: Apply Migrations¶

Generate the migrations for your models and apply them:

python manage.py makemigrations
python manage.py migrate

Step 8: Create Views for the App¶

In reviewmaster/views.py, create views to list users, businesses, and their details:

from django.shortcuts import render, get_object_or_404
from .models import User, Business

def user_index(request):
    users = User.objects.all()
    return render(request, 'reviewmaster/user_index.html', {'users': users})

def user_detail(request, user_id):
    user = get_object_or_404(User, pk=user_id)
    return render(request, 'reviewmaster/user_detail.html', {'user': user})

def business_index(request):
    businesses = Business.objects.all()
    return render(request, 'reviewmaster/business_index.html', {'businesses': businesses})

def business_detail(request, business_id):
    business = get_object_or_404(Business, pk=business_id)
    return render(request, 'reviewmaster/business_detail.html', {'business': business})

Step 9: Set Up URLs¶

In recsys/urls.py, include the URLs from the reviewmaster app:

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('reviewmaster/', include('reviewmaster.urls')),
    path('admin/', admin.site.urls),
]

In reviewmaster/urls.py, define the URLs for your views:

from django.urls import path
from . import views

urlpatterns = [
    path('users/', views.user_index, name='user_index'),
    path('users/<int:user_id>/', views.user_detail, name='user_detail'),
    path('businesses/', views.business_index, name='business_index'),
    path('businesses/<int:business_id>/', views.business_detail, name='business_detail'),
]

Step 10: Create Templates¶

Create a templates/reviewmaster/ folder for your HTML templates.
Add templates such as user_index.html, user_detail.html, business_index.html, and business_detail.html:

user_index.html:

{% if users %}
<ul>
    {% for user in users %}
    <li><a href="{% url 'user_detail' user.id %}">{{ user.name }}</a></li>
    {% endfor %}
</ul>
{% else %}
<p>No users are available.</p>
{% endif %}

user_detail.html:

<p>User Id: {{ user.id }}</p>
<p>User Name: {{ user.name }}</p>

Step 11: Admin Setup¶

Register the models in reviewmaster/admin.py so that you can manage them via the Django admin interface:

from django.contrib import admin
from .models import User, Business, Review

admin.site.register(User)
admin.site.register(Business)
admin.site.register(Review)

Create a superuser to access the Django admin panel:

python manage.py createsuperuser

Follow the prompts to create your admin account.

Step 12: Run the Development Server¶

Finally, run the server again to test your app:

python manage.py runserver

You can now visit:

http://127.0.0.1:8000/reviewmaster/users/ to view the list of users.
http://127.0.0.1:8000/reviewmaster/businesses/ to view the list of businesses.
http://127.0.0.1:8000/admin/ to manage users, businesses, and reviews via the admin interface.

![[Screen Shot 2024-10-08 at 22.24.56.png]]