Wagtail admin portal is using pure HTML and CSS. So everything coming to the python side is received via a HTML form. That means every button click in UI should associate with a HTML form and from wagtail side you can find it in the request.
Execute Action Method
If you went through the bulk action documentation, you will find that after the form is submitted, execute_action class method will be executed. Now you need to understand the parameters of this method.
@classmethod
def execute_action(cls, objects, **kwargs):
raise NotImplementedError("execute_action needs to be implemented")
As this is a class method, the first parameter is the class type which this method is on. You can learn more about class methods in the python documentation.
The 2nd parameter objects is the list of objects that you have selected for this bulk operation. To be precise, this is the list of objects that you have selected with the correct permission level. In the default implementation, permission is given for all the objects. But you can override this behavior.
def check_perm(self, obj):
return True
You can override this method in your custom bulk action class and check permission for each object. As the objects parameter, you will receive the only objects which have check_perm(obj)==True, from the list of objects you selected.
The 3rd parameter of execute_action class method is a keyworded argument list (a dictionary to be precise). This dictionary is obtained by calling the following method.
def get_execution_context(self):
return {}
Default behavior of this method is to return empty dictionary. But you can override this to send anything. Because execute_action is a class method, it can't access the instant variables. So this method is very helpful to pass instance variables to execute_action class method.
Lets look at an example.
@hooks.register('register_bulk_action')
class CustomBulkAction(ImageBulkAction):
display_name = _("A Thing")
aria_label = _("A thing to do")
action_type = "thing"
template_name = "appname/bulk/something.html"
def get_execution_context(self):
print(self.request)
return super().get_execution_context()
If you run this example, you can see the data submitted from the HTML form.
<WSGIRequest: POST '/admin/bulk/image/customimage/thing/?next=%2Fadmin%2Fimages%2F&id=1'>
Override the HTML Form
In the bulk action template, you can't find any HTML <form></form> tag. It is because the form with action buttons are in wagtailadmin/bulk_actions/confirmation/form.html file that you have import in the template. You can create the copy of that file and change it's behavior.
<form action="{{ submit_url }}" method="POST">
{% include 'wagtailadmin/shared/non_field_errors.html' %}
{% csrf_token %}
{% block form_fields %}
<!-- Custom Fields goes here -->
{% endblock form_fields %}
<input type="submit" value="{{ action_button_text }}" class="button {{ action_button_class }}" />
<a href="{{ next }}" class="button button-secondary">{{ no_action_button_text }}</a>
</form>
You can add custom fields you need in the area that I mentioned above sample code and values of those additional fields will be there in self.request.POST parameter. This is the easiest way to get something from the template to python side.
Django Forms
But that is not the best way. Django recommends using forms for these purposes. You can find more about Django forms in the documentation.
Almost every place that there is a form in a wagtail template, there is a associated Django form. In this case, the instance variable form_class is used to associate a bulk action template with a Django form.
class MyForm(forms.Form):
extra_field = forms.CharField(
max_length=100,
required=True,
)
@hooks.register('register_bulk_action')
class CustomBulkAction(ImageBulkAction):
display_name = _("A Thing")
aria_label = _("A thing to do")
action_type = "thing"
template_name = "appname/bulk/something.html"
form_class = MyForm
def get_execution_context(self):
print(self.cleaned_form.data)
return super().get_execution_context()
And very simply, I will add all the form fields to the template as in the below sample code.
<form action="{{ submit_url }}" method="POST">
{% include 'wagtailadmin/shared/non_field_errors.html' %}
{% csrf_token %}
{% block form_fields %}
{% for field in form %}
<div class="fieldWrapper">
{{ field.label_tag }} {{ field }}
{{ field.errors }}
</div>
{% endfor %}
{% endblock form_fields %}
<input type="submit" value="{{ action_button_text }}" class="button {{ action_button_class }}" />
<a href="{{ next }}" class="button button-secondary">{{ no_action_button_text }}</a>
</form>
Now this will print the data received from the HTML form. What we need to do is to pass the form data as kwargs to the execute_action class method.
Final Example
@hooks.register('register_bulk_action')
class CustomBulkAction(ImageBulkAction):
display_name = _("A Thing")
aria_label = _("A thing to do")
action_type = "thing"
template_name = "appname/bulk/something.html"
form_class = MyForm
def get_execution_context(self):
data = super().get_execution_context()
data['form'] = self.cleaned_form
return data
@classmethod
def execute_action(cls, objects, **kwargs):
print("KWARGS:", kwargs)
print(kwargs['form'].cleaned_data['extra_field'])
# Do what you want
return 0, 0
I believe this was helpful and answered all the questions related to bulk action submission.
With forms.ModelChoiceField in your form, you can get values from Django Models and pass them to the HTML field. You have to pass a queryset in the constructor.
extra_field = forms.ModelChoiceField(
required=True,
queryset=Collection.objects.order_by("name"),
)
