Django 国际化和本地化

from django.shortcuts import render
from django.utils.translation import gettext as _
from django.utils.translation import gettext_lazy, ngettext
from django.http import HttpResponse

def welcome_view(request):
    # 基本翻译
    message = _("Welcome to our website!")

    # 带变量的翻译
    username = request.user.username
    personalized_message = _("Hello, %(username)s!") % {'username': username}

    # 复数形式
    item_count = 5
    items_message = ngettext(
        "There is %(count)d item.",
        "There are %(count)d items.",
        item_count
    ) % {'count': item_count}

    context = {
        'message': message,
        'personalized_message': personalized_message,
        'items_message': items_message,
    }

    return render(request, 'welcome.html', context)

# 在模型中使用（使用 gettext_lazy）
from django.db import models
from django.utils.translation import gettext_lazy as _

class Product(models.Model):
    name = models.CharField(_("product name"), max_length=100)
    description = models.TextField(_("product description"))

    class Meta:
        verbose_name = _("product")
        verbose_name_plural = _("products")

    def __str__(self):
        return self.name

# 在表单中使用
from django import forms
from django.utils.translation import gettext_lazy as _

class ContactForm(forms.Form):
    name = forms.CharField(label=_("Your name"), max_length=100)
    email = forms.EmailField(label=_("Email address"))
    message = forms.CharField(
        label=_("Message"),
        widget=forms.Textarea,
        help_text=_("Please enter your message here.")
    )

# 在异常消息中使用
from django.core.exceptions import ValidationError
from django.utils.translation import gettext_lazy as _

def validate_even(value):
    if value % 2 != 0:
        raise ValidationError(
            _('%(value)s is not an even number'),
            params={'value': value},
        )

from django.utils.translation import pgettext, pgettext_lazy

# 相同单词在不同上下文中的翻译
# "Book" 作为名词（书）和动词（预订）
noun_book = pgettext("noun", "Book")
verb_book = pgettext("verb", "Book")

# 在模型中使用
class Reservation(models.Model):
    status = models.CharField(
        choices=[
            ('booked', pgettext_lazy("reservation status", "Booked")),
            ('confirmed', pgettext_lazy("reservation status", "Confirmed")),
        ],
        max_length=20
    )

# 创建消息文件（首次）
django-admin makemessages -l zh_Hans
django-admin makemessages -l ja
django-admin makemessages -l fr

# 创建所有语言的消息文件
django-admin makemessages -a

# 忽略特定目录
django-admin makemessages -l zh_Hans --ignore=venv/* --ignore=static/*

# 使用不同的扩展名（用于JavaScript）
django-admin makemessages -l zh_Hans -d djangojs

# 编译消息文件
django-admin compilemessages

# 编译特定语言
django-admin compilemessages -l zh_Hans

# 更新现有消息文件
django-admin makemessages -a --keep-pot

# 检查翻译完整性
django-admin makemessages --all --check

# 创建翻译目录结构
mkdir -p locale/zh_Hans/LC_MESSAGES
mkdir -p locale/ja/LC_MESSAGES

myproject/
├── manage.py
├── myproject/
│   ├── settings.py
│   ├── urls.py
│   └── ...
├── myapp/
│   ├── __init__.py
│   ├── models.py
│   ├── views.py
│   └── ...
└── locale/                   # 翻译文件目录
    ├── zh_Hans/
    │   └── LC_MESSAGES/
    │       ├── django.po     # 文本翻译文件
    │       └── django.mo     # 编译后的二进制文件
    ├── ja/
    │   �└── LC_MESSAGES/
    │       ├── django.po
    │       └── django.mo
    └── fr/
        └── LC_MESSAGES/
            ├── django.po
            └── django.mo

#: myapp/views.py:23
msgid "Welcome to our website!"
msgstr "欢迎访问我们的网站！"

#: myapp/models.py:45
msgid "product"
msgstr "产品"

#: myapp/models.py:46
msgid "products"
msgstr "产品"

#: templates/base.html:15
#, python-format
msgid "Hello, %(username)s!"
msgstr "你好，%(username)s！"

#: templates/shop.html:32
#, python-format
msgid "Your cart contains %(count)d items."
msgstr "您的购物车中有 %(count)d 件商品。"

#: templates/products.html:12
msgid "Search"
msgstr "搜索"

# 复数形式
#: myapp/views.py:67
#, python-format
msgid "There is %(count)d item."
msgid_plural "There are %(count)d items."
msgstr[0] "有 %(count)d 件商品。"
msgstr[1] "有 %(count)d 件商品。"

# 带上下文的翻译
#: myapp/forms.py:89
msgctxt "button"
msgid "Submit"
msgstr "提交"

#: myapp/forms.py:90
msgctxt "form"
msgid "Submit"
msgstr "表单提交"

from django.utils import timezone
from datetime import datetime, timedelta

def timezone_examples(request):
    # 获取当前时间（时区感知）
    now_aware = timezone.now()

    # 获取当前时间（时区非感知）
    now_naive = datetime.now()

    # 转换时区
    utc_time = now_aware.astimezone(timezone.utc)
    local_time = timezone.localtime(now_aware)  # 转换为当前时区

    # 创建时区感知日期时间
    from pytz import timezone as pytz_timezone
    beijing_tz = pytz_timezone('Asia/Shanghai')
    custom_time = timezone.make_aware(
        datetime(2023, 12, 25, 15, 30),
        beijing_tz
    )

    # 时区运算
    one_hour_later = now_aware + timedelta(hours=1)
    one_day_ago = now_aware - timedelta(days=1)

    # 在模板中使用的上下文
    context = {
        'now_aware': now_aware,
        'local_time': local_time,
        'utc_time': utc_time,
        'custom_time': custom_time,
        'one_hour_later': one_hour_later,
        'one_day_ago': one_day_ago,
    }

    return render(request, 'timezone_example.html', context)

# 在模型中使用时区
class Event(models.Model):
    title = models.CharField(max_length=200)
    start_time = models.DateTimeField()
    end_time = models.DateTimeField()

    def is_active(self):
        """检查事件是否正在进行"""
        now = timezone.now()
        return self.start_time <= now <= self.end_time

    def time_until_start(self):
        """距离开始还有多久"""
        now = timezone.now()
        if now < self.start_time:
            return self.start_time - now
        return None

    def duration(self):
        """事件持续时间"""
        return self.end_time - self.start_time

# 在表单中处理时区
from django import forms
from django.utils import timezone

class EventForm(forms.ModelForm):
    class Meta:
        model = Event
        fields = ['title', 'start_time', 'end_time']
        widgets = {
            'start_time': forms.DateTimeInput(attrs={'type': 'datetime-local'}),
            'end_time': forms.DateTimeInput(attrs={'type': 'datetime-local'}),
        }

    def clean(self):
        cleaned_data = super().clean()
        start_time = cleaned_data.get('start_time')
        end_time = cleaned_data.get('end_time')

        if start_time and end_time:
            # 确保开始时间在当前时间之后
            if start_time < timezone.now():
                raise forms.ValidationError("开始时间必须在当前时间之后")

            # 确保结束时间在开始时间之后
            if end_time <= start_time:
                raise forms.ValidationError("结束时间必须在开始时间之后")

        return cleaned_data

{% load tz %}

<!-- 设置时区 -->
{% timezone "Europe/Paris" %}
    <p>巴黎时间: {{ event.start_time }}</p>
{% endtimezone %}

{% timezone "Asia/Shanghai" %}
    <p>北京时间: {{ event.start_time }}</p>
{% endtimezone %}

<!-- 使用用户时区 -->
{% timezone user.timezone %}
    <p>您的时区: {{ event.start_time }}</p>
{% endtimezone %}

<!-- UTC 时间 -->
{% timezone "UTC" %}
    <p>UTC 时间: {{ event.start_time }}</p>
{% endtimezone %}

<!-- 时区转换 -->
<p>本地时间: {% localtime on %}{{ event.start_time }}{% endlocaltime %}</p>
<p>UTC 时间: {% localtime off %}{{ event.start_time }}{% endlocaltime %}</p>

<!-- 时区信息 -->
{% get_current_timezone as TIME_ZONE %}
<p>当前时区: {{ TIME_ZONE }}</p>

<!-- 相对时间 -->
{% load humanize %}
<p>开始时间: {{ event.start_time|naturaltime }}</p>
<p>{{ event.start_time|timesince }} 之前</p>
<p>{{ event.end_time|timeuntil }} 之后</p>

<!-- 事件状态 -->
{% if event.is_active %}
    <span class="badge bg-success">进行中</span>
{% elif event.start_time > now %}
    <span class="badge bg-warning">
        还有 {{ event.time_until_start|timeuntil }}
    </span>
{% else %}
    <span class="badge bg-secondary">已结束</span>
{% endif %}

<!-- 持续时间 -->
<p>持续时间: {{ event.duration }}</p>

# 时区设置
USE_TZ = True
TIME_ZONE = 'Asia/Shanghai'  # 默认时区

# 常用时区:
# TIME_ZONE = 'UTC'
# TIME_ZONE = 'US/Eastern'
# TIME_ZONE = 'Europe/London'
# TIME_ZONE = 'Asia/Tokyo'

# 在用户模型中存储时区偏好
class User(AbstractUser):
    timezone = models.CharField(
        max_length=50,
        default='Asia/Shanghai',
        choices=[
            ('UTC', 'UTC'),
            ('Asia/Shanghai', 'Asia/Shanghai'),
            ('Asia/Tokyo', 'Asia/Tokyo'),
            ('Europe/London', 'Europe/London'),
            ('US/Eastern', 'US/Eastern'),
        ]
    )

# 中间件设置用户时区
class TimezoneMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        if request.user.is_authenticated:
            timezone.activate(pytz.timezone(request.user.timezone))
        else:
            timezone.deactivate()

        return self.get_response(request)