2-capturing-overrides.rst

Chapter 2: Capturing Overrides

In the last chapter we configured our settings, and in this chapter we'll start to use those settings to capture overrides for different values.

Add components to the Homepage

Let's add the following components to the Homepage form:

• A Button named btn_submit, click event bound to btn_submit_click
• A Text Box named text_box_override
• A Text Box named text_box_comment

Once you're done, the Homepage form should look like this:

And now let's add the code:

from ._anvil_designer import HomepageTemplate
import anvil

from trexjacket.api import get_dashboard
from trexjacket import dialogs

class Homepage(HomepageTemplate):
  def __init__(self, **properties):
    self.dashboard = get_dashboard()
    self.init_components(**properties)

  @property
  def worksheet(self):
    # Here we use the settings we configured to dynamically get the worksheet
    return self.dashboard.get_worksheet(self.dashboard.settings['worksheet'])

  def btn_configure_click(self, **event_args):
    dialogs.show_form('configure_form', width=900, height=900)
    self.refresh_data_bindings()

  def btn_submit_click(self, **event_args):
    # If the user hasn't filled out the override and comment fields
    # and if they haven't selected anything, return
    if not all([
      self.text_box_override.text,
      self.text_box_comment.text,
      self.worksheet.get_selected_marks()[0]
    ]):
      return

    selected_record = self.worksheet.get_selected_marks()[0]
    anvil.Notification('We should save this!').show()

    # Reset our text boxes
    self.text_box_comment.text = ''
    self.text_box_override.text = None

Right now, if you enter an override and a comment and click the Submit button, you should see a notification but nothing else!

.. dropdown::
    :open:

    .. image:: https://extension-documentation.s3.amazonaws.com/tutorials/value-override/dummy_override.gif

This works, but let's start persisting this data using Anvil data tables.

Configure the data table

Let's create a data table named overrides with the following columns:

• id_field: Text
• id_value: Text
• override_field: Text
• override_value: Text
• on: Date and Time
• who: Text
• comment: Text

Make sure to select "Can search, edit and delete" next to permissions. We'd never do this in a production application but will for the tutorial.

.. dropdown::
    :open:

    .. image:: https://extension-documentation.s3.amazonaws.com/tutorials/value-override/allow_client_write.gif

Now let's add a data grid to the Homepage form with the following 4 column names and keys:

Name	Key
ID Field	id_field
ID Value	id_value
Override Field	override_field
Override Value	override_value

.. dropdown::
    :open:

    .. image:: https://extension-documentation.s3.amazonaws.com/tutorials/value-override/add_data_grid.gif

Now that we have our data table and UI set up, let's save the user's override and comment to our data table. Add the following code to the Homepage form:

from ._anvil_designer import HomepageTemplate
import anvil
from anvil.tables import app_tables
from datetime import datetime

from trexjacket.api import get_dashboard
from trexjacket import dialogs

class Homepage(HomepageTemplate):
  def __init__(self, **properties):
    self.dashboard = get_dashboard()
    self.repeating_panel_1.items = app_tables.overrides.search()
    self.init_components(**properties)

  @property
  def worksheet(self):
    # Here we use the settings we configured to dynamically get the worksheet
    return self.dashboard.get_worksheet(self.dashboard.settings['worksheet'])

  def btn_configure_click(self, **event_args):
    dialogs.show_form('configure_form', width=900, height=900)
    self.refresh_data_bindings()

  def btn_submit_click(self, **event_args):
    # If the user hasn't filled out the override and comment fields
    # and if they haven't selected anything, return
    if not all([
      self.text_box_override.text,
      self.text_box_comment.text,
      self.worksheet.get_selected_marks()[0]
    ]):
      return

    selected_record = self.worksheet.get_selected_marks()[0]

    app_tables.overrides.add_row(
      id_value = selected_record[self.dashboard.settings['id_field']],
      id_field = self.dashboard.settings['id_field'],
      override_field = self.dashboard.settings['override_field'],
      override_value = self.text_box_override.text,
      who = selected_record[self.dashboard.settings['username']],
      comment = self.text_box_comment.text,
      on = datetime.now()
    )
    self.repeating_panel_1.items = app_tables.overrides.search()
    anvil.Notification('Override saved!').show()

    # Reset our text boxes
    self.text_box_comment.text = ''
    self.text_box_override.text = None

Now reload your extension in Tableau and you should be able to add a comment and an override!

.. dropdown::
    :open:

    .. image:: https://extension-documentation.s3.amazonaws.com/tutorials/value-override/save_override.gif

In the next chapter we'll connect Tableau directly to our data table so we can add the overrides to the dashboard tooltip.