How do I show the error to the user when initializing the Django form?

I'm trying to do the following. The form should upload a text file. If it is not present, the form should not be loaded. An error should appear instead.

class SemanticAiForm(forms.Form):
    semantic_folder = configurate.AI_DATA_FOLDER
    semantic_files = 'ai_openai_fresh_news.txt'

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        semantic = self.get_semantic()
        if semantic is None:
            self.add_error(NON_FIELD_ERRORS, 'No data')
        else:
            self.fields['order'] = forms.CharField(widget=forms.Textarea())
            self.fields['order'].initial = semantic.system_content

    def get_semantic(self) -> Union[SemanticTxt, None]:
        """
        Получает объект SemanticTxt с прочитанным файлом параметрической
        конфигурации.
        """

        try:
            filepath = os.path.join(self.semantic_folder, self.semantic_files)
            semantic = read_semantic(filepath)

        except exception.SemanticError:
            return

        return semantic

If there is a file, everything is fine. If there is no file, on the contrary. Django reports:

'SemanticAiForm' object has no attribute 'cleaned_data'

I'm trying to do something else. If there is no file, display an error in the template. And don't show the form. What am I doing wrong?

UPDATE

class RustpdAdminSite(admin.AdminSite):
"""
Переопределение админ-части создаёт пространство для творчества.
"""

def get_urls(self):
    urls = super().get_urls()

    custom_urls = [
        path('semantic-ai/',
             self.admin_view(views_admin.SemanticAiGPT.as_view(
                 admin_context=self.each_context)
             ),
             name='semantic'),
    ]

    return custom_urls + urls

The view function is called via views_admin. Perhaps it matters?

  1. Update the form class as follows:

    class SemanticAiForm(forms.Form): semantic_folder = configurate.AI_DATA_FOLDER semantic_files = 'ai_openai_fresh_news.txt'

     def __init__(self, *args, **kwargs):
     super().__init__(*args, **kwargs)
     self.is_valid_file = True

     semantic = self.get_semantic()
     if semantic is None:
         self.is_valid_file = False
     else:
         self.fields['order'] = forms.CharField(widget=forms.Textarea())
         self.fields['order'].initial = semantic.system_content

 def get_semantic(self) -> Union[SemanticTxt, None]:
     try:
         filepath = os.path.join(self.semantic_folder, self.semantic_files)
         semantic = read_semantic(filepath)
     except exception.SemanticError:
         return None
     return semantic

 def is_bound(self):
     return super().is_bound() and self.is_valid_file

 def is_valid(self):
     if not self.is_valid_file:
         return False
     return super().is_valid()

  2. Update your view as follows:

    def your_view(request): form = SemanticAiForm() if form.is_valid_file: if request.method == 'POST': form = SemanticAiForm(request.POST) if form.is_valid(): # Your form processing code pass else: error_message = "File not found or couldn't be read." return render(request, 'your_template.html', {'error_message': error_message})

     return render(request, 'your_template.html', {'form': form})

  3. Update your template as follows:

    {% if error_message %} {{ error_message }}

    {% else %} {% csrf_token %} {{ form.as_p }} Submit {% endif %}

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