Messaging Problem

Anvil Q&A
1

I’m trying to use Anvil Extras Messaging to pass a message from a row template to the parent form. I thought I’d got my head around it but clearly not.
The idea is that clicking a link in the row template deletes the item (this bit works) and this sends a message. In the parent form the message handler refreshes the form.

What I’ve tried and what’s not working:
I have module named ‘common’ in which a Publisher is created

from anvil_extras.messaging import Publisher

publisher = Publisher()

In the row template (RowTemplate5) I import the publisher

from ...common import publisher

and I have a handler for the link_click which tries to publish the message

  @handle("lnkDeleteAccount", "click")
  def lnkDeleteAccount_click(self, **event_args):
    un = self.item['username']
    fn = self.item['forename']
    sn = self.item['surname']
    ar = alert("Are you sure you want to delete the member " + fn + ' ' + sn + " (" + un + ")", large=True, title='Delete Member?', buttons=[('Yes','y'),('No','n')])
    if ar == 'y':
      pass
      #delete the user
      rowtodelete = app_tables.users.get(username=un)
      rowtodelete.delete()
      #delete yns
      self.RemoveYNs(un)
      #refresh main form
88  publisher.publish(channel="Members", title="Member Deleted")

When I click the link the code in the handler runs, deleting the record I want deleted. but the attempt to publish the message fails with this error:-
TypeError: 'NoneType' object is not callable

  • at app/anvil_extras/messaging.py:52
  • called from frmAdminMembers.RowTemplate5, line 88

Can anyone see what I’m doing wrong?

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2

it’s this line in your code

publisher.subscribe(channel="Members", subscriber=self, handler=self.RefreshMembersTable())

it should be

publisher.subscribe(channel="Members", subscriber=self, handler=self.RefreshMembersTable)

i.e. don’t pass the result of calling a function as the handler
instead pass in the function itself

3

Doh! Well caught stucork and thanks again.

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