Added TemplateColumn.value() and enhanced export docs (fixes #470)

django_tables2/columns/templatecolumn.py

@@ -3,6 +3,8 @@
 
 from django.template import Context, Template
 from django.template.loader import get_template
+from django.utils import six
+from django.utils.html import strip_tags
 
 from .base import Column, library
 
@@ -63,3 +65,14 @@ def render(self, record, table, value, bound_column, **kwargs):
                 return get_template(self.template_name).render(context.flatten())
         finally:
             context.pop()
+
+    def value(self, **kwargs):
+        '''
+        The value returned from a call to `value()` on a `TemplateColumn` is
+        the rendered tamplate with `django.utils.html.strip_tags` applied.
+        '''
+        html = super(TemplateColumn, self).value(**kwargs)
+        if isinstance(html, six.string_types):
+            return strip_tags(html)
+        else:
+            return html

docs/pages/custom-data.rst

@@ -87,14 +87,16 @@ argument.
     a default value is rendered instead (both `.Column.render` and
     ``Table.render_FOO`` are skipped).
 
+.. _table.value_foo:
+
 `Table.value_foo` methods
 -------------------------
 
 If you want to use `Table.as_values` to export your data, you might want to define
 a method ``value_foo``, which is analogous to ``render_foo``, but used to render the
 values rather than the HTML output.
 
-Please refer to `~.Table.as_values` for an example.
+Please refer to `.Table.as_values` for an example.
 
 .. _subclassing-column:
 

docs/pages/export.rst

@@ -52,6 +52,23 @@ If you must use a function view, you might use someting like this::
             'table': table
         })
 
+What exacly is exported?
+------------------------
+
+The export views use the `.Table.as_values()` method to get the data from the table.
+Because we often use HTML in our table cells, we need to specify something else for the
+export to make sense.
+
+If you use :ref:`table.render_foo`-methods to customize the output for a column,
+you should define a :ref:`table.value_foo`-method, returning the value you want
+to be exported.
+
+If you are creating your own custom columns, you should know that each column
+defines a `value()` method, which is used in `Table.as_values()`.
+By default, it just calls the `render()` method on that column.
+If your custom column produces HTML, you should override this method and return
+the actual value.
+
 
 Excluding columns
 -----------------

tests/columns/test_templatecolumn.py

@@ -74,3 +74,12 @@ class Table(tables.Table):
 
     table = Table([{'track': 'Beat it {Freestyle}'}])
     assert table.rows[0].get_cell('track') == 'track: Beat it {Freestyle}'
+
+
+def test_should_strip_tags_for_value():
+    class Table(tables.Table):
+        track = tables.TemplateColumn('<span>{{ value }}</span>')
+
+    table = Table([{'track': 'Space Oddity'}])
+
+    assert list(table.as_values()) == [['Track'], ['Space Oddity']]