Flask WTForms - option_widget for SelectMultipleField? - flask

I have a field in my Flask WTForm which uses a SelectMultipleField. I'm using a frontend library which renders the choices fine from the db and adds them to the input field as tags when I select them (like the tags do on this website when creating a question!).
However the data is not being saved, form.field.data and request.form.getlist('field') etc all show None. If I add option_widget=widgets.CheckboxInput to the SelectMultipleField, I can select and save data.
So what I'm wondering is, do I need make a custom field or widget in order for the form to use the selected options as the form data (for example, instead of checking if the field has been checked, it checks if it's in the input field). Going a bit mad reading all the documentation so grateful for a hint in the right direction! Code below:
field = SelectMultipleField(
"fieldname",
validators=[Optional()],
widget=widgets.ListWidget(prefix_label=False),
# option_widget=CheckboxInput(),
)

please try this way
from flask_appbuilder.fieldwidgets import Select2ManyWidget
"users": QuerySelectMultipleField(
_("group.user"),
query_factory=lambda: db.session.query(User),
widget=Select2ManyWidget(),
default=[],
),
The result will look like the image below

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I'm using wagtail CMS for Django, I want to add a dynamically populated value for a dropdown and save it on the Page model, this is my code:
class MyPage(Page):
domain = CharField(max_length=10, choices=MY_CHOICES)
subdomain = CharField(max_length=10, choices=[('', '------')]
I've got some frontend logic to populate dynamically the options for subdomain, but after I hit save I got: The page could not be created due to validation errors And in the subdomain field: Select a valid choice. [my value] is not one of the available choices.
I can't use ForeignKey to populate subdomain because it depends from an external API service that we're using.
I tried to use a custom field that inherits from CharField with no success, it looks it executes validate method only for the domain field.
If you use the choices argument, you have to predefine the list of possible values. Read the relevant part of the docs (last two paragraphs of that section).
You could omit the choices argument from the model field definition and only render a HTML select tag in the frontend (which is then filled with options dynamically, like you explained).
You could also look into changing the default widget of the CharField to a select tag, like this answer and this part of the docs show.

Linear Scale Django form widget

I am looking for some guidance in order to create a widget that is not documented at all in the django documentation but is an evident part of forms.
And I am talking about Linear Scales widgets for forms. Giving the ability to a user to choose on a scale between 1-100 a score
If you have any idea on how to do it, any direction I would be please to get it ;)
thx you very much
I'm guessing that you want a type="range" input as you can find in this MDN page.
Django doesn't provide this kind of field out of the box and you have to do it yourself or find a library that implements it.
To implement a field you should look at the Field API and the Input API.
# example input
from django.form.widgets import Input
class RangeInput(Input):
input_type = 'range'
template_name = 'path/to/input/template.html'
You should also implement type coercion (to int of float) and range checking to be sure that you can validate a form and store it appropriately in the db.
Once you have done that you can create your form with this input or create a new RangeField for models and link it to the RangeInput element.

Using jquery autocomplete Django form

I am using jquery autocomplete with my generic views on Django. I am getting the list via AJAX, but there is one problem. When the user get the category he wants, he will select that value. Thus, if I append the value on that field $("#id_category").val(ui.item.value); it will show the pk on that field instead of value, so if I append $("#id_category").val(ui.item.label); django will complain it should be the instance. Django is completely right. How to make this work?
Edit:
I have made id_category hidden field and added category_display to append the text value. It is working. But while editing the category_display would be empty. Again I am using generic view. How to solve this one on the edit?
I had similar issue and I suggest you to think about question: 'What will happen if user enters not valid category name(category with this name doesn`t exist)?'
if you need to accept entered value and add new category, you have to make clean_category method in form:
def clean_category(self):
name = self.data['category']
return Category.objects.get_or_create(name=name)[0]
and display ui.item.label for user
if new category isn`t acceptable you can raise error in clean_category method or use something like select2(http://ivaynberg.github.io/select2/) for your field. I choose second variant.

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I have a couple of fields in my model that to which I wish to add a link that will allow the user to search for names/files (external from the application's database).
So what I would like is:
Field name: [text box] - LINK
Is there a straightforward django way of achieving this?
Cheers.
You need to change the widget that the form field uses to display the models information. You basically add some html after the input to link to where you want.
Here's some code I put together to create a widget that displays how many characters are left for a CharacterField so it's similar to what you are looking to do:
https://github.com/pastylegs/django-widget-charsleft/blob/master/widget_charsleft/widgets.py