Django 无法处理非 ascii 符号答案

【问题标题】：Django can't process non-ascii symbolsDjango 无法处理非 ascii 符号
【发布时间】：2019-01-11 10:28:11
【问题描述】：

我们有一个奇怪的问题。如果我们在 Django 中使用非 ascii 符号，它会在列表中正常显示它们，

但如果我们尝试输入该项目，它会出现以下错误：

sys.setdefaultencoding("utf-8") 有帮助，但有人认为这是错误的方法 (Why should we NOT use sys.setdefaultencoding("utf-8") in a py script?)。我怎样才能正确解决它？为什么列表正确显示？任何想法表示赞赏！

完整的追溯：

Environment:


Request Method: GET
Request URL: http://127.0.0.1:8000/enter/event/23/change/

Django Version: 1.9.4
Python Version: 2.7.10
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'debug_toolbar',
 'enter']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'debug_toolbar.middleware.DebugToolbarMiddleware']


Template error:
In template /Library/Python/2.7/site-packages/django/contrib/admin/templates/admin/change_form.html, error at line 21
   ascii   11 : {% block coltype %}colM{% endblock %}
   12 : 
   13 : {% block bodyclass %}{{ block.super }} app-{{ opts.app_label }} model-{{ opts.model_name }} change-form{% endblock %}
   14 : 
   15 : {% if not is_popup %}
   16 : {% block breadcrumbs %}
   17 : <div class="breadcrumbs">
   18 : <a href="{% url 'admin:index' %}">{% trans 'Home' %}</a>
   19 : &rsaquo; <a href="{% url 'admin:app_list' app_label=opts.app_label %}">{{ opts.app_config.verbose_name }}</a>
   20 : &rsaquo; {% if has_change_permission %}<a href="{% url opts|admin_urlname:'changelist' %}">{{ opts.verbose_name_plural|capfirst }}</a>{% else %}{{ opts.verbose_name_plural|capfirst }}{% endif %}
   21 : &rsaquo; {% if add %}{% trans 'Add' %} {{ opts.verbose_name }}{% else %} {{ original|truncatewords:"18" }} {% endif %}
   22 : </div>
   23 : {% endblock %}
   24 : {% endif %}
   25 : 
   26 : {% block content %}<div id="content-main">
   27 : {% block object-tools %}
   28 : {% if change %}{% if not is_popup %}
   29 :   <ul class="object-tools">
   30 :     {% block object-tools-items %}
   31 :     <li>


Traceback:

File "/Library/Python/2.7/site-packages/django/core/handlers/base.py" in get_response
  174.                     response = self.process_exception_by_middleware(e, request)

File "/Library/Python/2.7/site-packages/django/core/handlers/base.py" in get_response
  172.                     response = response.render()

File "/Library/Python/2.7/site-packages/django/template/response.py" in render
  160.             self.content = self.rendered_content

File "/Library/Python/2.7/site-packages/django/template/response.py" in rendered_content
  137.         content = template.render(context, self._request)

File "/Library/Python/2.7/site-packages/django/template/backends/django.py" in render
  95.             return self.template.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  206.                     return self._render(context)

File "/Library/Python/2.7/site-packages/django/test/utils.py" in instrumented_test_render
  92.     return self.nodelist.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)

File "/Library/Python/2.7/site-packages/django/template/loader_tags.py" in render
  173.         return compiled_parent._render(context)

File "/Library/Python/2.7/site-packages/django/test/utils.py" in instrumented_test_render
  92.     return self.nodelist.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)

File "/Library/Python/2.7/site-packages/django/template/loader_tags.py" in render
  173.         return compiled_parent._render(context)

File "/Library/Python/2.7/site-packages/django/test/utils.py" in instrumented_test_render
  92.     return self.nodelist.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)

File "/Library/Python/2.7/site-packages/django/template/defaulttags.py" in render
  326.                 return nodelist.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)

File "/Library/Python/2.7/site-packages/django/template/loader_tags.py" in render
  69.                 result = block.nodelist.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)

File "/Library/Python/2.7/site-packages/django/template/defaulttags.py" in render
  326.                 return nodelist.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in render
  1043.             output = self.filter_expression.resolve(context)

File "/Library/Python/2.7/site-packages/django/template/base.py" in resolve
  736.                 new_obj = func(obj, *arg_vals)

File "/Library/Python/2.7/site-packages/django/template/defaultfilters.py" in _dec
  47.             args[0] = force_text(args[0])

File "/Library/Python/2.7/site-packages/django/utils/encoding.py" in force_text
  80.                 s = six.text_type(bytes(s), encoding, errors)

Exception Type: UnicodeEncodeError at /enter/event/23/change/
Exception Value: 'ascii' codec can't encode character u'\xe9' in position 29: ordinal not in range(128)

【问题讨论】：

请发布完整的回溯（作为文本）。还要检查您的settings.DEFAULT_CHARSET 和您的数据库编码（表和客户端）。
你的settings.DEFAULT_CHARSET 是什么？您的模型字段标签或 help_text 中是否有重音字符？您是仅在某些记录上还是在所有记录上都存在此问题？如果尝试从管理员创建新事件，您是否有问题？
@scharette django 使用“unicode 三明治”模式，因此模板需要 unicode 字符串并负责对其进行编码。
@Arkady 不检查您的代码就无法判断 - 这里有很多因素在起作用，包括您是否使用 from __future__ import unicode_literals 和/或您是否正确使用 u"" unicode 前缀，如果您的源代码中有# -*- coding: <encoding_name> 标头，您的__unicode__ 方法是如何实现的以及诸如此类的... wrt/ settings.DEFAULT_CHARSET 如果未设置，则默认为utf-8，并且由于您的错误消息明确提及在 ascii 编解码器中，它确实不是罪魁祸首。
作为一般规则：如果您想安全起见，您希望始终只在代码中使用 unicode，特别是对于文字字符串。 Django 本身在系统入口点（HTTP 查询、数据库查询等）将所有内容转换为 unicode。

标签： python django utf-8 ascii

【解决方案1】：

就我而言，用 __ unicode__ 替换 __ str__ 方法会有所帮助，但正如@bruno-desthuilliers 所说，这里有很多因素在起作用

# def __str__(self):
#     return str(self.id) +': ' + self.title

def __unicode__(self):
    return u'%s: %s' % (self.id, self.title)

【讨论】：

您绝对不想从__unicode__() 返回str！它必须是一个 unicode 字符串。这里的正确实现是return u"{}: {}".format(self.id, self.title)