Dash all-in-one component (AIO) - why is the nested `Ids` class exposed as `ids`

Dash Python
1

I am trying to understand the idea behind exposing the nested Ids class as ids as is shown in the Dash all-in-one component tutorial:

# Make the Ids class a public class
ids = Ids

Why create the ids variable when external users can also just directly call the Ids class?

I asked chatGPT on some ideas for this. It came up with:

While it’s technically possible to directly call the Ids class itself, doing so would break encapsulation and make the code harder to understand and maintain. By using the ids attribute, the developers are signaling that the Ids class is an implementation detail that should not be accessed directly.

and

Accessing the Ids class directly versus accessing it through the ids attribute of the AIOI class doesn’t provide any additional functionality. Both ways provide access to the same methods and properties of the Ids class.

However, the way these are accessed can have implications on the code’s readability, maintainability, and encapsulation. Accessing Ids directly might suggest that it’s an independent entity that can be used separately, which might not be the case. On the other hand, accessing it through ids makes it clear that it’s a part of the AIO class, and should be used in that context.

In summary, the difference isn’t about what users can do, but about how the code communicates its design and intent.

That reasoning seems to make some sense. Additionally, I can also imagine that this brings some uniformity across AIO components, as this gives developers freedom in how they name the nested identity classes or to have more classes for ids, for example to separate private vs public ids. Then users can always just access ids to get access to the ids of all available subcomponents.

Can anyone comment on this? Is this the full reasoning, or am I missing some other logic here?

2

Hello @Tobs,

Believe you hit the nail on the hear with this one.

If you provide the underlying ids you can customize and develop callbacks based upon the underlying component. :slight_smile:

3

develop callbacks based upon the underlying component.

Do you have specific examples of this where the usage would be different for AIO developers versus AIO users?

The thing about this topic that throws me off a bit is the mention of a public class. Somehow I associate that with the class otherwise not being available (which isn’t the case in Python). So somehow I get the feeling I am missing something. Though, it seems I am not:p

4

Sure, first lets breakdown some definitions:

  • AIO developer: developer designing the component, creating inputs, callbacks within the component, etc.
  • AIO user: developer creating interactions with the component, needs access to the component ids for triggers and updates.

Now, lets take a look at one designed by @AnnMarieW:

If you look in the code, for the ThemeChanger example you can see that there is a callback like this:

@app.callback(
    Output("graph", "figure"), Input(ThemeChangerAIO.ids.radio("theme"), "value"),
)
def update_graph_theme(theme):
    return px.bar(
        df, x="Fruit", y="Amount", color="City", barmode="group", template=template_from_url(theme)
    )

Now, this above callback could have been written like this:

Input({
            "component": "ThemeChangerAIO",
            "subcomponent": "radio",
            "aio_id": "theme",
        }, "value")

This would have the same effect, but much easier to write as ThemeChangerAIO.ids.radio("theme").

Inside the component itself, these ids are used as inputs and outputs for callbacks as well.

It is also possible, that since you know the ids of the underlying components, the AIO user could design interactions or alterations that the AIO developer didnt have in mind when designing the component.

Hope this helps.

5

Clear, in that case we are on the same page and I am not missing anything. Thanks for the explanation!

1 Like