python之如何使用 App Engine 获取 Jinja2 中继承模板的特定回溯

每当我的 App Engine 项目中继承的 Jinja2 模板出现错误时，我都会得到一个回溯，它仅指定导致继承的行，而不是导致错误的行。

例如，我用两个模板创建了一个虚拟项目，page.html 和 base.html。 page.html 继承自 base.html 并且 base.html 具有旨在导致错误的行。 App Engine/Jinja 不会在 base.html 中报告错误，而是会给我以下回溯:

Traceback (most recent call last): 
  File "/home/kkinder/Software/google_appengine/lib/webapp2/webapp2.py", line 1536, in __call__ 
    rv = self.handle_exception(request, response, e) 
  File "/home/kkinder/Software/google_appengine/lib/webapp2/webapp2.py", line 1530, in __call__ 
    rv = self.router.dispatch(request, response) 
  File "/home/kkinder/Software/google_appengine/lib/webapp2/webapp2.py", line 1278, in default_dispatcher 
    return route.handler_adapter(request, response) 
  File "/home/kkinder/Software/google_appengine/lib/webapp2/webapp2.py", line 1102, in __call__ 
    return handler.dispatch() 
  File "/home/kkinder/Software/google_appengine/lib/webapp2/webapp2.py", line 572, in dispatch 
    return self.handle_exception(e, self.app.debug) 
  File "/home/kkinder/Software/google_appengine/lib/webapp2/webapp2.py", line 570, in dispatch 
    return method(*args, **kwargs) 
  File "/home/kkinder/Projects/JinjaTestProject/main.py", line 11, in get 
    self.response.out.write(self.jinja2.render_template('page.html')) 
  File "/home/kkinder/Software/google_appengine/lib/webapp2/webapp2_extras/jinja2.py", line 158, in render_template 
    return self.environment.get_template(_filename).render(**context) 
  File "/home/kkinder/Software/google_appengine/lib/jinja2/jinja2/environment.py", line 894, in render 
    return self.environment.handle_exception(exc_info, True) 
  File "templates/page.html", line 1, in top-level template code 
    {% extends 'base.html' %} 
UndefinedError: 'doesnotexist' is undefined 

主要.py:

import webapp2 
from webapp2_extras import jinja2 
 
class MainHandler(webapp2.RequestHandler): 
    @webapp2.cached_property 
    def jinja2(self): 
        return jinja2.get_jinja2(app=self.app) 
 
    def get(self): 
        self.response.out.write(self.jinja2.render_template('page.html')) 
 
app = webapp2.WSGIApplication([('/', MainHandler)], 
                             debug=True) 

页面.html:

{% extends 'base.html' %} 
{% block content %} 
    Stuff 
{% endblock %} 

基础.html:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 
<head> 
</head> 
<body> 
<h1>{{ doesnotexist.foo }}</h1> 
    {% block content %}{% endblock %} 
</body> 
</html> 

请您参考如下方法:

不幸的是，在生产环境中，不可能在 GAE 上获得更好的 Jinja2 调试信息，因为它们限制了对所需包的访问。您可以在官方FAQ: My tracebacks look weird. What’s happening?上找到有关此问题的更多信息。