After init of the form, is it impossible to modify the media js list?

white-seolpyo · July 11, 2024, 9:01am

I want to modify form.Media according to the received arg without setting it in advance.

After super().__init__(), self.media._js and self.media._js_lists are checked in self.media.__dir__().
However, neither of them could be modified or added.

Is it impossible to fix this??

KenWhitesell · July 12, 2024, 2:54pm

See the docs for Media as a dynamic property, and the related sections for Media on Forms, I believe that would allow you to customize its configuration based upon what exists within the form.

white-seolpyo · July 13, 2024, 12:04am

Your answer is not helpful.

white-seolpyo · July 13, 2024, 12:06am

A solution I found myself.
The form’s media is provided as a property, and a new Media class is created each time it is called.

Therefore, if you want to do this, you need to add a Media class to the form and override the action to be performed when calling the media property.

github.com

django/django/blob/main/django/forms/forms.py#L373


      
              return self.cleaned_data
          
          def has_changed(self):
              """Return True if data differs from initial."""
              return bool(self.changed_data)
          
          @cached_property
          def changed_data(self):
              return [name for name, bf in self._bound_items() if bf._has_changed()]
          
          @property
          def media(self):
              """Return all media required to render the widgets on this form."""
              media = Media()
              for field in self.fields.values():
                  media += field.widget.media
              return media
          
          def is_multipart(self):
              """
              Return True if the form needs to be multipart-encoded, i.e. it has

Additionally, the Media class used in the form uses Media from widgets.py, and writing a Media class within a form as mentioned in the Django document is a method of overriding and using the variable of the Media class.

github.com

django/django/blob/main/django/forms/widgets.py#L61


      
              "SelectDateWidget",
          )
          
          MEDIA_TYPES = ("css", "js")
          
          
          class MediaOrderConflictWarning(RuntimeWarning):
              pass
          
          
          @html_safe
          class Media:
              def __init__(self, media=None, css=None, js=None):
                  if media is not None:
                      css = getattr(media, "css", {})
                      js = getattr(media, "js", [])
                  else:
                      if css is None:
                          css = {}
                      if js is None:
                          js = []

When using {{ form.media }} in a template, the self.render() method connected to self.__str__() is used.

github.com

django/django/blob/main/django/forms/widgets.py#L93


      
              css = defaultdict(list)
              for css_list in self._css_lists:
                  for medium, sublist in css_list.items():
                      css[medium].append(sublist)
              return {medium: self.merge(*lists) for medium, lists in css.items()}
          
          @property
          def _js(self):
              return self.merge(*self._js_lists)
          
          def render(self):
              return mark_safe(
                  "\n".join(
                      chain.from_iterable(
                          getattr(self, "render_" + name)() for name in MEDIA_TYPES
                      )
                  )
              )
          
          def render_js(self):
              return [

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After init of the form, is it impossible to modify the media js list?

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