ইন্টারন্যাশনালাইজেশন ও লোকালাইজেশন:

django-admin startproject multilingual_api
cd multilingual_api

python manage.py startapp products

multilingual_api/
│
├── multilingual_api/
│   ├── __init__.py
│   ├── asgi.py
│   ├── settings.py
│   ├── urls.py
│   ├── wsgi.py
│
├── products/                        # Your Django app for products
│   ├── __init__.py
│   ├── admin.py
│   ├── apps.py
│   ├── migrations/
│   ├── models.py
│   ├── views.py
│   ├── urls.py
│   └── templates/
│       └── products/
│           ├── product_list.html
│           └── change_language.html
│
├── locale/                          # Locale directory for translations
│   ├── bn/
│   │   └── LC_MESSAGES/
│   │       └── django.po            # Bengali translations
│   ├── hi/
│   │   └── LC_MESSAGES/
│   │       └── django.po            # Hindi translations
│   └── zh/
│       └── LC_MESSAGES/
│           └── django.po            # Chinese translations
│
└── manage.py

# settings.py

INSTALLED_APPS = [
    ...
    'rest_framework',
    'products',
]

# settings.py
from django.utils.translation import gettext_lazy as _

LANGUAGES = [
    ('en', 'English'),
    ('bn', 'Bengali'),
    ('hi', 'Hindi'),
    ('zh', 'Chinese'),
]

LOCALE_PATHS = [
    BASE_DIR / 'locale',
]

MIDDLEWARE = [
    ...
    'django.middleware.locale.LocaleMiddleware',
    ...
]

# products/models.py
from django.db import models
from django.utils.translation import gettext_lazy as _

class Product(models.Model):
    name = models.CharField(_("Product Name"), max_length=255)
    description = models.TextField(_("Description"))
    price = models.DecimalField(_("Price"), max_digits=10, decimal_places=2)

    def __str__(self):
        return self.name

python manage.py makemigrations
python manage.py migrate

# products/serializers.py
from rest_framework import serializers
from .models import Product
from django.utils.translation import gettext_lazy as _

class ProductSerializer(serializers.ModelSerializer):
    name = serializers.CharField(source='name', label=_("Product Name"))
    description = serializers.CharField(source='description', label=_("Description"))

    class Meta:
        model = Product
        fields = ['id', 'name', 'description', 'price']

# products/views.py
from django.utils import translation
from rest_framework import generics, views, status
from rest_framework.response import Response
from rest_framework.permissions import AllowAny
from .models import Product
from .serializers import ProductSerializer

class ProductListCreateView(generics.ListCreateAPIView):
    queryset = Product.objects.all()
    serializer_class = ProductSerializer

class ChangeLanguageView(views.APIView):
    permission_classes = [AllowAny]

    def post(self, request):
        language = request.data.get('language')

        if language in dict(settings.LANGUAGES):
            translation.activate(language)
            request.session[translation.LANGUAGE_SESSION_KEY] = language
            return Response({"message": "Language changed successfully."}, status=status.HTTP_200_OK)
        else:
            return Response({"error": "Invalid language code."}, status=status.HTTP_400_BAD_REQUEST)

class GetLanguagesView(views.APIView):
    permission_classes = [AllowAny]

    def get(self, request):
        languages = dict(settings.LANGUAGES)
        return Response(languages, status=status.HTTP_200_OK)

# products/urls.py
from django.urls import path
from .views import ProductListCreateView, ChangeLanguageView, GetLanguagesView

urlpatterns = [
    path('products/', ProductListCreateView.as_view(), name='product-list-create'),
    path('change-language/', ChangeLanguageView.as_view(), name='change-language'),
    path('get-languages/', GetLanguagesView.as_view(), name='get-languages'),
]

# multilingual_api/urls.py
from django.urls import path, include

urlpatterns = [
    path('api/', include('products.urls')),
]

django-admin makemessages -l bn   # বাংলা ভাষার জন্য
django-admin makemessages -l hi   # হিন্দি ভাষার জন্য
django-admin makemessages -l zh   # চাইনিজ ভাষার জন্য

msgid "Product Name"
msgstr "পণ্যের নাম"

msgid "Description"
msgstr "বর্ণনা"

msgid "Price"
msgstr "মূল্য"

django-admin compilemessages

python manage.py runserver

npx create-react-app multilingual-app
cd multilingual-app

npm install axios

// src/App.js
import React, { useEffect, useState } from 'react';
import axios from 'axios';

const App = () => {
    const [products, setProducts] = useState([]);
    const [languages, setLanguages] = useState([]);
    const [selectedLanguage, setSelectedLanguage] = useState('en');

    useEffect(() => {
        fetchProducts();
        fetchLanguages();
    }, [selectedLanguage]);

    const fetchProducts = async () => {
        const response = await axios.get('http://127.0.0.1:8000/api/products/', {
            headers: { 'Accept-Language': selectedLanguage }
        });
        setProducts(response.data);
    };

    const fetchLanguages = async () => {
        const response = await axios.get('http://127.0.0.1:8000/api/get-languages/');
        setLanguages(response.data);
    };

    const changeLanguage = async (language) => {
        await axios.post('http://127.0.0.1:8000/api/change-language/', { language });
        setSelectedLanguage(language);
    };

    return (
        <div>
            <h1>Products</h1>
            <select onChange={(e) => changeLanguage(e.target.value)}>
                {Object.entries(languages).map(([code, name]) => (
                    <option key={code} value={code}>
                        {name}
                    </option>
                ))}
            </select>
            <ul>
                {products.map(product => (
                    <li key={product.id}>
                        <h2>{product.name}</h2>
                        <p>{product.description}</p>
                        <p>{product.price}</p>
                    </li>
                ))}
            </ul>
        </div>
    );
};

export default App;

npm start

django-admin startproject multilingual_site
cd multilingual_site

python manage.py startapp products

# settings.py
from django.utils.translation import gettext_lazy as _

INSTALLED_APPS = [
    ...
    'products',
]

LANGUAGES = [
    ('en', 'English'),
    ('bn', 'Bengali'),
    ('hi', 'Hindi'),
    ('zh', 'Chinese'),
]

LOCALE_PATHS = [
    BASE_DIR / 'locale',  # Translation files path
]

MIDDLEWARE = [
    ...
    'django.middleware.locale.LocaleMiddleware',
    ...
]


# Template settings (no changes needed, but include necessary dirs)
TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [BASE_DIR / 'templates'],  # Your global templates directory
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
                
            ],
        },
    },
]

# products/models.py
from django.db import models
from django.utils.translation import gettext_lazy as _

class Product(models.Model):
    name = models.CharField(_("Product Name"), max_length=255)
    description = models.TextField(_("Description"))
    price = models.DecimalField(_("Price"), max_digits=10, decimal_places=2)

    def __str__(self):
        return self.name

python manage.py makemigrations
python manage.py migrate

RestApiProject/
├── products/
│   ├── __init__.py
│   ├── models.py
│   ├── views.py
│   ├── context_processors.py  # <- Add this file here
│   └── ...
├── anotherapp/
└── ...

from django.conf import settings

def languages(request):
    return {'LANGUAGES': settings.LANGUAGES}

# settings.py
TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, 'templates')],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
                'products.context_processors.languages',  # <- Update this line
            ],
        },
    },
]

# products/views.py
from django.shortcuts import render
from django.utils import translation
from .models import Product

def product_list(request):
    products = Product.objects.all()
    return render(request, 'products/product_list.html', {'products': products})

def change_language(request):
    if request.method == 'POST':
        language = request.POST.get('language')
        if language in dict(request.LANGUAGES):
            translation.activate(language)
            request.session[translation.LANGUAGE_SESSION_KEY] = language
    return render(request, 'products/change_language.html')

<!-- templates/products/product_list.html -->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>{% trans "Product List" %}</title>
</head>
<body>
    <h1>{% trans "Product List" %}</h1>
    <ul>
        {% for product in products %}
            <li>
                <h2>{{ product.name }}</h2>
                <p>{{ product.description }}</p>
                <p>{{ product.price }}</p>
            </li>
        {% endfor %}
    </ul>
    <a href="{% url 'change_language' %}">{% trans "Change Language" %}</a>
</body>
</html>

<!-- templates/products/change_language.html -->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>{% trans "Change Language" %}</title>
</head>
<body>
    <h1>{% trans "Change Language" %}</h1>
    <form action="" method="POST">
        {% csrf_token %}
        <select name="language">
            <option value="en">English</option>
            <option value="bn">বাংলা</option>
            <option value="hi">हिंदी</option>
            <option value="zh">中文</option>
        </select>
        <button type="submit">{% trans "Change Language" %}</button>
    </form>
</body>
</html>

# products/urls.py
from django.urls import path
from .views import product_list, change_language

urlpatterns = [
    path('products/', product_list, name='product_list'),
    path('change-language/', change_language, name='change_language'),
]

# multilingual_site/urls.py
from django.urls import path, include

urlpatterns = [
    path('', include('products.urls')),
]

django-admin makemessages -l bn   # বাংলা ভাষার জন্য
django-admin makemessages -l hi   # হিন্দি ভাষার জন্য
django-admin makemessages -l zh   # চাইনিজ ভাষার জন্য

msgid "Product List"
msgstr "পণ্যের তালিকা"

msgid "Change Language"
msgstr "ভাষা পরিবর্তন করুন"

django-admin compilemessages

python manage.py runserver