Datatables View Ext: Null / NoneType Front-End Label Option & Helper

changes/7574.feature

@@ -0,0 +1,6 @@
+Added `ckan.datatables.null_label` config option.
+
+Added `datatablesview_null_label` helper.
+
+Datatables Views will now show blank cells
+for NoneType field values by default.

ckanext/datatablesview/blueprint.py

@@ -122,8 +122,10 @@ def ajax(resource_view_id: str):
         dtdata = {u'error': query_error}
     else:
         data = []
+        null_label = h.datatablesview_null_label()
         for row in response[u'records']:
-            record = {colname: str(row.get(colname, u''))
+            record = {colname: str(null_label if row.get(colname, u'')
+                                   is None else row.get(colname, u''))
                       for colname in cols}
             # the DT_RowId is used in DT to set an element id for each record
             record['DT_RowId'] = 'row' + str(row.get(u'_id', u''))

ckanext/datatablesview/config_declaration.yaml

@@ -93,3 +93,9 @@ groups:
       the user to view, copy and print the details of a specific row. This
       value can be overridden at the resource level when configuring a
       DataTables resource view.
+
+  - key: ckan.datatables.null_label
+    example: N/A
+    description: |
+      The option defines the label used to display NoneType values for the front-end.
+      This should be a string and can be translated via po files.

ckanext/datatablesview/helpers.py

@@ -0,0 +1,5 @@
+from ckan.plugins.toolkit import _, config
+
+
+def datatablesview_null_label():
+    return _(config.get('ckan.datatables.null_label', u''))

ckanext/datatablesview/plugin.py

@@ -2,11 +2,11 @@
 from __future__ import annotations
 
 from ckan.common import CKANConfig
-from typing import Any, cast
+from typing import Any, cast, Callable
 from ckan.types import Context, ValidatorFactory
 import ckan.plugins as p
 import ckan.plugins.toolkit as toolkit
-from ckanext.datatablesview import blueprint
+from ckanext.datatablesview import blueprint, helpers
 
 default = cast(ValidatorFactory, toolkit.get_validator(u'default'))
 boolean_validator = toolkit.get_validator(u'boolean_validator')
@@ -22,6 +22,7 @@ class DataTablesView(p.SingletonPlugin):
     p.implements(p.IConfigurer, inherit=True)
     p.implements(p.IResourceView, inherit=True)
     p.implements(p.IBlueprint)
+    p.implements(p.ITemplateHelpers)
 
     # IBlueprint
 
@@ -96,3 +97,8 @@ def info(self) -> dict[str, Any]:
                 u'filterable': [default(True), boolean_validator],
             }
         }
+
+    # ITemplateHelpers
+
+    def get_helpers(self) -> dict[str, Callable[..., object]]:
+        return {'datatablesview_null_label': helpers.datatablesview_null_label}