I can't use accented letters in my model

[Virgilio Ravagli]

Hi everybody.

I defined a model class, Book, whose field title may contain accented letters.

But in the case, when the instruction save() is executed, I receive an error saying that "You must not use 8-bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str)".

So. my question is: how can I use accented letters ?

[Antonis Christofides]

Please provide the minimum code that reproduces the problem, and the full traceback.

Regards,

Antonis

[Virgilio Ravagli]

All right.

class Book(models.Model):

       code = models.PositiveIntegerField(primary_key=True)

       title = models.CharField(max_length=60,blank=False,null=False)

book = Book()

book.code = 1

book.title = 'Verità'

book.save()

the code is really simple

[Antonis Christofides]

Please read my email again.

Antonis Christofides
+30-6979924665 (mobile)

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[Virgilio Ravagli]

I have surround book.save with a try...catch...; the exception is: You must not use 8-bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings.

Without the try...catch, here is the traceback:

Environment:


Request Method: POST
Request URL: http://localhost:8000/uti/dataLoading/

Django Version: 1.8.5
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',
 'uti')
Installed Middleware:
('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',
 'django.middleware.security.SecurityMiddleware')


Traceback:
File "C:\Python27\lib\site-packages\django\core\handlers\base.py" in get_response
  132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\RavagliV\eclipse-workspace-saved\librarian\uti\views.py" in datLoading
  34.                 msg = do_dat_loading()
File "C:\Users\RavagliV\eclipse-workspace-saved\librarian\uti\views.py" in do_dat_loading
  79.             book.save()
File "C:\Python27\lib\site-packages\django\db\models\base.py" in save
  734.                        force_update=force_update, update_fields=update_fields)
File "C:\Python27\lib\site-packages\django\db\models\base.py" in save_base
  762.             updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "C:\Python27\lib\site-packages\django\db\models\base.py" in _save_table
  827.                                       forced_update)
File "C:\Python27\lib\site-packages\django\db\models\base.py" in _do_update
  877.         return filtered._update(values) > 0
File "C:\Python27\lib\site-packages\django\db\models\query.py" in _update
  580.         return query.get_compiler(self.db).execute_sql(CURSOR)
File "C:\Python27\lib\site-packages\django\db\models\sql\compiler.py" in execute_sql
  1062.         cursor = super(SQLUpdateCompiler, self).execute_sql(result_type)
File "C:\Python27\lib\site-packages\django\db\models\sql\compiler.py" in execute_sql
  840.             cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py" in execute
  79.             return super(CursorDebugWrapper, self).execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py" in execute
  64.                 return self.cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\utils.py" in __exit__
  97.                 six.reraise(dj_exc_type, dj_exc_value, traceback)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py" in execute
  64.                 return self.cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\sqlite3\base.py" in execute
  318.         return Database.Cursor.execute(self, query, params)

Exception Type: ProgrammingError at /uti/dataLoading/
Exception Value: You must not use 8-bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings.

[o1bigtenor]

On Fri, Jun 10, 2022 at 2:50 AM Virgilio Ravagli
<virgilio...@gmail.com> wrote:
>
> I have surround book.save with a try...catch...; the exception is: You must not use 8-bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings.
> Without the try...catch, here is the traceback:
> Environment:
>
>
> Request Method: POST
> Request URL: http://localhost:8000/uti/dataLoading/
>
> Django Version: 1.8.5
> Python Version: 2.7.10

Hmmmmmmmm - - - - not speaking as any kind of expert - - - - but - - - -
Python 2.xx has been deprecated for some time now. Python 3.10 is
current. Likewise Django is now at version 3.2 for long-term support
and is at 4.0.5 for current. AIUI you may find that your issue has already
been addressed.

HTH

[Virgilio Ravagli]

I'm bound to use old versions of Python and Django, cannot pass to newer versions in this project

[o1bigtenor]

On Fri, Jun 10, 2022 at 6:15 AM Virgilio Ravagli
<virgilio...@gmail.com> wrote:
>
> I'm bound to use old versions of Python and Django, cannot pass to newer versions in this project
>

https://python.readthedocs.io/en/v2.7.2/howto/unicode.html

maybe that helps

You may also have a severe case of 'can't get there from here' - - -
meaning it may be a no can do.

HTH

[Antonis Christofides]

Hello,

try this:

book.title = u'Verità'

Regards,

Antonis

P.S. Sorry I was a bit harsh yesterday—I had drunk too much beer :-)

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/e2df5c07-5dd3-4fc3-9034-1955d438b670n%40googlegroups.com.

[Virgilio Ravagli]

Thank you, Antonis, it works !

book.title = u'Verità' doesn't give any errors.

Just another step: suppose that the title with accented letters stays in a variable, say titolo, and I want to write

book.title = titolo. It gives error. How can I do, when the assignment on the right is not a constant ?

Thanks in advance

[Virgilio Ravagli]

I found a way: book.title = titolo.decode('unicode_escape')

it works fine

[Antonis Christofides]

Exactly. The important thing to remember here is that, in Python 2, a "string" is actually a list of bytes, whereas a "unicode string" is actually a list of characters (not a list of unicode characters—just a list of characters). The confusion arises because, when Python was created, i.e. in 1990, multi-byte characters were in their infancy, and we mostly assumed that a character and a byte was more or less the same thing.

In Python 3, the Python 2 "strings" were renamed to "bytes", and the Python 2 "unicode strings" were renamed to "strings"—and the syntax for the literals of these types also changed. This made it way better.

More information about all this is in https://djangodeployment.com/2017/06/19/encodings-part-1/.

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/fb8bed42-b1f9-4aba-aa9d-c87b06cc774cn%40googlegroups.com.

[Ryan Nowakowski]

This is a good primer on bytes vs strings:

https://www.joelonsoftware.com/2003/10/08/the-absolute-minimum-every-software-developer-absolutely-positively-must-know-about-unicode-and-character-sets-no-excuses/