实时语言切换

问题:

如何实现实时语言切换？

解法:

  1. import os
  2. import sys
  3. import gettext
  4. import web
  6. # File location directory.
  7. rootdir = os.path.abspath(os.path.dirname(__file__))
  9. # i18n directory.
  10. localedir = rootdir + '/i18n'
  12. # Object used to store all translations.
  13. allTranslations = web.storage()
  15. def get_translations(lang='en_US'):
  16.     # Init translation.
  17.     if allTranslations.has_key(lang):
  18.         translation = allTranslations[lang]
  19.     elif lang is None:
  20.         translation = gettext.NullTranslations()
  21.     else:
  22.         try:
  23.             translation = gettext.translation(
  24.                     'messages',
  25.                     localedir,
  26.                     languages=[lang],
  27.                     )
  28.         except IOError:
  29.             translation = gettext.NullTranslations()
  30.     return translation
  32. def load_translations(lang):
  33.     """Return the translations for the locale."""
  34.     lang = str(lang)
  35.     translation  = allTranslations.get(lang)
  36.     if translation is None:
  37.         translation = get_translations(lang)
  38.         allTranslations[lang] = translation
  40.         # Delete unused translations.
  41.         for lk in allTranslations.keys():
  42.             if lk != lang:
  43.                 del allTranslations[lk]
  44.     return translation
  46. def custom_gettext(string):
  47.     """Translate a given string to the language of the application."""
  48.     translation = load_translations(session.get('lang'))
  49.     if translation is None:
  50.         return unicode(string)
  51.     return translation.ugettext(string)
  53. urls = (
  54.     '/', 'index'
  55. )
  57. render = web.template.render('templates/',
  58.         globals={
  59.             '_': custom_gettext,
  60.             }
  61.         )
  63. app = web.application(urls, globals())
  65. # Init session.
  66. session = web.session.Session(app,
  67.         web.session.DiskStore('sessions'),
  68.         initializer={
  69.             'lang': 'en_US',
  70.             }
  71.         )
  73. class index:
  74.     def GET(self):
  75.         i = web.input()
  76.         lang = i.get('lang', 'en_US')
  78.         # Debug.
  79.         print >> sys.stderr, 'Language:', lang
  81.         session['lang'] = lang
  82.         return render.index()
  84. if __name__ == "__main__": app.run()

模板文件: templates/index.html.

  1. $_('Hello')

不要忘记生成必要的po&mo语言文件。参考: 模板语言中的i18n支持

现在运行code.py:

  1. $ python code.py
  2. http://0.0.0.0:8080/

然后用你喜欢的浏览器访问下面的地址，检查语言是否改变:

  1. http://your_server:8080/
  2. http://your_server:8080/?lang=en_US
  3. http://your_server:8080/?lang=zh_CN

你必须:

  • 确保语言文件(en_US、zh_CN等)可以动态改变。

  • 确保custom_gettext()调用越省资源越好。参考:

  • 这里有使用app.app_processor()的 另一个方案。