Add additional attributes to td (and other elements) after the table was created

[zelenij]

Please take a look at this discussion on SO: https://stackoverflow.com/questions/44525828/django-tables2-updating-attrs-has-no-effect/44546087

In essence, I want to be able to inject some additional attributes into the td element after the table was created. The table in question is based on a model, and therefore the columns are generated automatically, rather than being crafted one by one, providing a chance to set the parameters there. There is a way to hack it at the moment, but it feels it's using an undocumented API and such is brittle.

[zelenij]

Upon further testing I can see that my hack doesn't actually work, so the problem is still open

[jieter]

@zelenij thanks for reporting.
The suggestion in the stackoverflow answer was actually not that bad: you could do this with the extra_columns keyword argument:

class MyTable(tables.Table):
    class Meta:
        model = Person
        fields = ('first_name', 'last_name')

table = MyTable(queryset, extra_columns=[
    ('first_name', tables.Column(attrs={'td': {'style': 'color: red;'}}))
])

will add the style="color: red" html attribute to the <td> tags rendered for this column. Does this support your use case?

[zelenij]

It's a step in the right direction. Is there an easy way to do the same generically on all the columns of an existing table instance? It's a given that these columns can be some unknown derived classes of tablesColumn

[jieter]

Not really. May I ask, what is your exact usecase?

Issue #253 might be another step? Thoughts?

[zelenij]

What I'm trying to do is to stamp on each td (cell) the name of it's header, in order to then use CSS tricks for nice rendering on mobile. One description of the CSS trick is here: https://elvery.net/demo/responsive-tables/ (the last section on the page).

There are alternatives, for example I could use jQuery to achieve the same, but I prefer to restrict the usage of JavaScript as much as realistically possible.

[jieter]

Interesting technique. Did you look into creating a custom template for the django-tables2 table?

[zelenij]

Yes, it's an option. However, from that moment onwards I'll have to keep my custom template in sync with the "official" one, which over the long term might prove annoying.

[jieter]

Yes, I understand. And I also think it should be easier to override attrs for columns table-wide. We already have row_attrs, we could also just add column_attrs...
But adding more and more to the Table constructor has its limits. So maybe someone can think of another way...

[zelenij]

Maybe have a method which would allow to inject it?

[jieter]

@zelenij while I was fixing this, it turned out to be kind of supported already, see #457.

Please test this by installing the branch using
pip install -U https://github.com/bradleyayers/django-tables2/archive/td-attrs.zip
and this syntax:

class Table(tables.Table):
    class Meta:
        attrs = {
           'td': {'data-name': lambda column: column.name}
        }

[zelenij]

Yes, this seems to do the trick, thanks!

[jieter]

released 1.9.0