UnicodeDecodeError : 'ascii' codec can't decode byte 0xe0 in position 0: ordinal not in range(128)


On one of my machines I have the error when I am working with google apps engine or django.

For example:

  • app.yaml

    application: demas1252c
    version: 1
    runtime: python
    api_version: 1
       - url: /images
    static_dir: images
       - url: /css
    static_dir: css
       - url: /js
    static_dir: js
       - url: /.*
    script: demas1252c.py
  • demas1252c.py

    import cgi
    import wsgiref.handlers
    from google.appengine.ext.webapp import template
    from google.appengine.ext import webapp
    class MainPage(webapp.RequestHandler): 
    def get(self):
    values = {'id' : 10}
    self.response.out.write(template.render('foto.html', values))
    application = webapp.WSGIApplication([('/', MainPage)], debug = True)
  • foto.html

    <!DOCTYPE html>
    <html lang="en">

error message:

C:\artefacts\dev\project>"c:\Program Files\Google\google_appengine\dev_appserver.py" foto-hosting
Traceback (most recent call last):
  File "c:\Program Files\Google\google_appengine\dev_appserver.py", line 69, in <module>
    run_file(__file__, globals())
  File "c:\Program Files\Google\google_appengine\dev_appserver.py", line 65, in run_file
    execfile(script_path, globals_)
  File "c:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver_main.py", line 92, in <module>
    from google.appengine.tools import dev_appserver
  File "c:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 140, in <module>
    mimetypes.add_type(mime_type, '.' + ext)
  File "C:\Python27\lib\mimetypes.py", line 344, in add_type
  File "C:\Python27\lib\mimetypes.py", line 355, in init
  File "C:\Python27\lib\mimetypes.py", line 260, in read_windows_registry
    for ctype in enum_types(mimedb):
  File "C:\Python27\lib\mimetypes.py", line 250, in enum_types
    ctype = ctype.encode(default_encoding) # omit in 3.x!
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe0 in position 0: ordinal not in range(128)

When I am working with static files in django (without gae) I have very similar error (with different stack).

I tried to find the reason of error and added code to mimetypes.py:

print '====='
print ctype
ctype = ctype.encode(default_encoding) # omit in 3.x!

Then I get next messages in my console:

Traceback (most recent call last):

In the registry HKCR/Mime/Database/ContentType/ I have five keys with russian (cyrilic) letters. But how can I fix this error?

11/21/2010 1:07:25 PM

Accepted Answer

This is a bug in mimetypes, triggered by bad data in the registry. (рєфшю/AMR is not at all a valid MIME media type.)

ctype is a registry key name returned by _winreg.EnumKey, which mimetypes is expecting to be a Unicode string, but it isn't. Unlike _winreg.QueryValueEx, EnumKey returns a byte string (direct from the ANSI version of the Windows API; _winreg in Python 2 doesn't use the Unicode interfaces even though it returns Unicode strings, so it'll never read non-ANSI characters correctly).

So the attempt to .encode it fails with a Unicode​Decode​Error trying to get a Unicode string before encoding it back to ASCII!

    ctype = ctype.encode(default_encoding) # omit in 3.x!
except UnicodeEncodeError:

These lines in mimetypes should simply be removed.

ETA: added to bug tracker.

11/21/2010 2:14:22 PM

By the way, the main culpit of the problem is QuickTime which adds non-ascii mime types to the windows registry. The easiest way to fix it is to manually find and remove from the registry the subsections of the HKCR/Mime/Database/ContentType/ starting with аудио/ and видео/.

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