How to solve a UnicodeDecodeError?

Question

I get a strange error message when trying to read non-ascii from the datastore:

'ascii' codec can't decode byte 0xc3 in position 5: ordinal not in range(128)
Traceback (most recent call last):
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/webapp2.py", line 1511, in __call__
    rv = self.handle_exception(request, response, e)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/webapp2.py", line 1505, in __call__
    rv = self.router.dispatch(request, response)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/webapp2.py", line 1253, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/webapp2.py", line 1077, in __call__
    return handler.dispatch()
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/handler.py", line 127, in dispatch
    response = super(NewBaseHandler, self).dispatch()
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/webapp2.py", line 547, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/webapp2.py", line 545, in dispatch
    return method(*args, **kwargs)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/handler.py", line 73, in check_login
    return handler(self, *args, **kwargs)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/handler.py", line 526, in get
    user=user)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/handler.py", line 91, in render_jinja
    **template_args))
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/webapp2_extras/jinja2.py", line 158, in render_template
    return self.environment.get_template(_filename).render(**context)
  File "/base/data/home/apps/s~myapp-www/events.355951895377615944/jinja2/environment.py", line 894, in render
    return self.environment.handle_exception(exc_info, True)
  File "template_files/my_organization.html", line 148, in top-level template code
    <li id="{{ person.key.id()|makeid }}" class="level_1 inactive   leaf"><a href="" style="" class=""><ins>&nbsp;</ins><table class="leaf_info"><tbody>    <tr><td class="name">{{ person.firstname }} {{ person.lastname}} {{person.key.id()|makeid}}</td><td class="level" title="New Distributor"><span class="level_parseable">1</span>1</td><td class="downlines">0</td><td class="cc_personal"><span class="cc_personal_parseable"></span>0</td><td class="cc_downlines"><span class="cc_downlines_parseable"></span>0</td><td class="cc_activity"><span class="cc_activity_parseable"></span>0</td><td class="cc_nonmanager"><span class="cc_nonmanager_parseable"></span>0</td><td class="cc_total"><span class="cc_total_parseable"></span>0</td></tr></tbody></table></a></li>{% endfor %}
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 5: ordinal not in range(128)

The loop that used to work is ordinary:

{% for person in people %}
    <li id="{{ person.key.id()|makeid }}" class="level_1 inactive   leaf">
<a href="" style="" class=""><ins>&nbsp;</ins><table class="leaf_info"><tbody>  <tr><td class="name">{{ person.firstname }} {{ person.lastname}} {{person.key.id()|makeid}}</td><td class="level" title="New Distributor"><span class="level_parseable">1</span>1</td><td class="downlines">0</td><td class="cc_personal"><span class="cc_personal_parseable"></span>0</td><td class="cc_downlines"><span class="cc_downlines_parseable"></span>0</td><td class="cc_activity"><span class="cc_activity_parseable"></span>0</td><td class="cc_nonmanager"><span class="cc_nonmanager_parseable"></span>0</td><td class="cc_total"><span class="cc_total_parseable"></span>0</td></tr></tbody></table></a></li>
{% endfor %}

What can I do to resolve this error?

My handler looks like this

class Myorg(NewBaseHandler):
    @user_required
    def get(self):
        user = auth_models.User.get_by_id(long(self.auth.get_user_by_session()['user_id']))
        people = auth_models.User.query(auth_models.User.sponsor == user.key).fetch()
        self.render_jinja('my_organization.html', people=people,
                              user=user)

And my model definition is the User model from webapp2. Here is also my custom filer makeid:

def makeid(n, countrycode="46"):
    countrycode = str(countrycode)
    n = str(n)
    return "%s%s%s" % (countrycode, '0'*(12-len(countrycode)-len(n)), n)

Update

The workaround is strange, I just make a .decode('utf-8') which is shouldn't need to be doing:

class UpdateHandler(NewBaseHandler):

    @user_required
    def get(self):
        user = \
            auth_models.User.get_by_id(long(self.auth.get_user_by_session()['user_id'
                ]))
        sponsor = None
        if user.sponsor:
            sponsor = user.sponsor.get()
        address = None
        if user.address:
            address = user.address.decode('utf-8')
        if user.city:
            city = user.city.decode('utf-8')
        self.render_jinja('details.html', city=city, user=user, address=address, sponsor=sponsor, form=UpdateForm(obj=user))

Is there any way to decode the all of the variables of the user object at once instead of one by one?

Answer 1

The best was is to get the string converted to ASCII character set. You may use the python encode cgi function to convert to ASCII

s = string_1.encode("ascii", "ignore")

Example

Answer 2

You're attempting to interpolate a raw (byte) string into a Unicode template. This is done by attempting to decode the raw string into unicode using some encoding - here, the default 'ascii' encoding - which is failing because it's encountering a codepoint that isn't valid for ASCII.

To fix this, you need to pass only unicode strings into your template - decode the string using the correct codec before passing it in.

Answer 3

Cast the text/HTML you pass to the template as Unicode and you should see it go away. Have had this problem before with Django templates in GAE with webapp2.