Add optional `context_object_name` to `TemplateColumn` and make `extra_context` optionally callable by jieter · Pull Request #931 · jieter/django-tables2

jieter · 2023-10-17T09:49:34Z

fixes: #928

…a_context` optionally callable fixes: #928

danielvdp

Interessant. Ik heb wat vragen en suggesties

django_tables2/columns/templatecolumn.py

danielvdp · 2023-10-25T13:40:07Z

django_tables2/columns/templatecolumn.py

        }
-        additional_context.update(self.extra_context)
+
+        extra_context = self.extra_context


ik vind "additional" en "extra" content wel dubbelop? Waar is additional voor en waar is extra voor? Kunnen we de namen niet wat aanpassen in termen van waar ze voor dienen?

I tried to improve on this

danielvdp · 2023-10-25T13:42:09Z

django_tables2/columns/templatecolumn.py

-        additional_context.update(self.extra_context)
+
+        extra_context = self.extra_context
+        if callable(extra_context):


ik had uit de docstring begrepen dat extra_context een dict was - dus dan zou ik de callable meegeven in een dict ... maar blijkbaar moet je een callable toewijzen aan extra_context? Dus voor mij is de docstring van verwarrend

You should return a callable returning a dict.

I tried to clarify it in the docstring.

danielvdp · 2023-10-25T13:49:51Z

tests/columns/test_templatecolumn.py

+        table = Table([{"name": "Bob"}])
+        self.assertEqual(list(table.as_values()), [["Name"], ["Bob"]])
+
+    def test_extra_context_callable(self):


test voor extra context dict was er al toch?

Nope, just added one.

danielvdp · 2023-10-25T13:51:30Z

tests/columns/test_templatecolumn.py

+    def test_extra_context_callable(self):
+        class Table(tables.Table):
+            size = tables.TemplateColumn(
+                "{{ size }}", extra_context=lambda record: {"size": record["clothes"]["size"]}


ik zou het wel beter vinden als er meer optional arguments getest zouden worden? table / value / bound column - ik zie niet goed hoe dat hier terug komt.

I added another column with value.

federicobond · 2025-03-18T07:16:03Z

Would it make sense to extract context building so it can be done in an overrideable get_context_data method?

Here's an example use case where I want to resolve a second accessor and pass it to the template. This is the original code:

class NameAndDescriptionColumn(tables.Column):
    def __init__(self, *args, **kwargs):
        description_accessor = kwargs.pop("description_accessor", "description")
        super().__init__(*args, **kwargs)
        self.description_accessor = (
            Accessor(description_accessor) if description_accessor else None
        )

    def render(self, record):
        return format_html(
            """<span class="h5">{name}</span>
            <br>
            <span class="fs-5 text-body">{description}</span>""",
            name=self.accessor.resolve(record),
            description=self.description_accessor.resolve(record),
        )

With a get_context_data method, I could transform it into a TemplateColumn subclass with an idiomatic Django API:

class NameAndDescriptionColumn(tables.TemplateColumn):
    template_code = """<span class="h5">{{ value }}</span><br>
        <span class="fs-5 text-body">{{ description }}</span>"""

    def __init__(self, *args, **kwargs):
        description_accessor = kwargs.pop("description_accessor", "description")
        super().__init__(*args, **kwargs)
        self.description_accessor = (
            Accessor(description_accessor) if description_accessor else None
        )

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx["description"] = self.description_accessor.resolve(ctx["record"])
        return ctx

This is arguably more flexible than passing callable to extra_context, but I'm not sure how well you think it fits with the django_tables2 design.

federicobond · 2025-11-28T23:18:30Z

Hi @jieter, I'm keen to move this forward. How can I help?

Would you be interested in reviewing a rebased PR with a changelog entry if I make one?

…plate-column

Co-authored-by: danielvdp <danielvdp@users.noreply.github.com>

jieter · 2025-12-22T15:03:10Z

Would it make sense to extract context building so it can be done in an overrideable get_context_data method?

Excellent idea, I updated the PR to use that pattern.

@federicobond If you can review the current state of the PR I think we can get this released quickly.

federicobond

I left a couple of comments. One thought: it might be helpful to add a short note in the docs about overriding get_context_data in TemplateColumn subclasses.

For use cases that need more complex or dynamic context, defining a custom column (similar to class-based views) feels quite idiomatic in Python/Django:

class MyColumn(TemplateColumn):
    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx["some_variable"] = my_function(ctx["record"])
        return ctx

Compared to a lambda-based extra_context, which can become a bit harder to read once the logic grows:

my_column = TemplateColumn(
    extra_context=lambda record: {"some_variable": my_function(record)}
)

Totally optional, but having this mentioned somewhere in the docs could help steer users toward the pattern that best fits their use case.

federicobond · 2026-01-05T04:00:48Z

django_tables2/columns/templatecolumn.py

+        # attaches the context to the table as a gift to `TemplateColumn`.
+        parent_context = getattr(table, "context", Context())
+
+        with parent_context.update(self.get_context_data(table=table, **kwargs)):


Nit: I'd extract local variable context for readability.

Suggested change

with parent_context.update(self.get_context_data(table=table, **kwargs)):

context = self.get_context_data(table=table, **kwargs)

with parent_context.update(context):

federicobond · 2026-01-05T04:03:36Z

django_tables2/columns/templatecolumn.py

-        # attaches the context to the table as a gift to `TemplateColumn`.
-        context = getattr(table, "context", Context())
-        additional_context = {
+    def get_context_data(self, record, table, value, bound_column, **kwargs):


Should these be kwargs-only? A specific positional argument order can make the API harder to change later

Suggested change

def get_context_data(self, record, table, value, bound_column, **kwargs):

def get_context_data(self, *, record, table, value, bound_column, **kwargs):

jieter added 2 commits October 17, 2023 12:09

Add optional context_object_name to TemplateColumn and make `extr…

9ef248a

…a_context` optionally callable fixes: #928

Use relative import

7691bf3

jieter force-pushed the feature/improve-template-column branch from cba0965 to 7691bf3 Compare October 17, 2023 10:09

jieter mentioned this pull request Oct 17, 2023

Feature request: Make TemplateColumn more dynamic #928

Closed

Add basic docs, remove stub get_context_data

fe78309

jieter force-pushed the feature/improve-template-column branch from 475dd3d to fe78309 Compare October 17, 2023 12:12

danielvdp self-requested a review October 25, 2023 13:24

danielvdp reviewed Oct 25, 2023

View reviewed changes

rixx mentioned this pull request Oct 15, 2025

Pass request to TemplateColumn #1008

Closed

jieter and others added 7 commits December 22, 2025 15:33

Merge remote-tracking branch 'origin/master' into feature/improve-tem…

f3f41f1

…plate-column

Apply suggestions from code review

1d8bc79

Co-authored-by: danielvdp <danielvdp@users.noreply.github.com>

Code formatting tweaks

9baf943

TemplateColumn.get_context_data()

416b128

Extend test to use 'value'

6e89b28

Add test for extra_context as dict

3d76700

Fix test

70f9955

federicobond reviewed Jan 5, 2026

View reviewed changes

	with parent_context.update(self.get_context_data(table=table, **kwargs)):
	context = self.get_context_data(table=table, **kwargs)
	with parent_context.update(context):

	def get_context_data(self, record, table, value, bound_column, **kwargs):
	def get_context_data(self, , record, table, value, bound_column, *kwargs):

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jieter commented Oct 17, 2023

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federicobond commented Mar 18, 2025

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federicobond commented Nov 28, 2025

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jieter commented Dec 22, 2025

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