Resource View
The tables plugin implements CKAN's IResourceView interface, which means it can act as a resource view — a built-in CKAN mechanism that allows you to preview resource data directly on a dataset resource page, without writing any custom code.
Once the plugin is active, CKAN will automatically offer a Tables View option whenever a resource is in one of the supported formats.
Supported Formats
The view is available for resources whose Format field (case-insensitive) is one of:
| Format | Data Source |
|---|---|
csv |
CsvUrlDataSource |
xlsx |
XlsxUrlDataSource |
orc |
OrcUrlDataSource |
parquet |
ParquetUrlDataSource |
feather |
FeatherUrlDataSource |
If the resource has been pushed to the CKAN Datastore (i.e. its datastore_active flag is True), the DataStoreDataSource is used regardless of the format field, providing direct and efficient access to stored records without any caching overhead.
Caching
For file-based data sources (CSV, XLSX, ORC, Parquet, Feather), fetched data is cached with a default TTL of 3600 seconds (1 hour), configurable via ckanext.tables.cache.ttl. The cache backend is configurable:
| Config value | Backend |
|---|---|
feather (default) |
Disk-based feather (Arrow IPC) files |
parquet |
Disk-based parquet files |
pickle |
Disk-based pickle files |
redis |
CKAN's Redis connection |
# Switch to Redis
ckanext.tables.cache.backend = redis
# Or keep the default feather backend and customise the cache directory
ckanext.tables.cache.backend = feather
ckanext.tables.cache.cache_dir = /var/cache/ckanext-tables
The Datastore-backed view does not use caching — it queries the Datastore API directly on every request.
An expired entry is deleted the next time it's read, but one that's never read again after expiring (a removed or renamed resource, for example) would otherwise stay on disk indefinitely. For the file-based backends, run the following periodically (e.g. from a cron job) to sweep away anything past its TTL:
ckan -c /etc/ckan/default/ckan.ini tables clean-cache
The Redis backend already expires and removes its own keys, so this command is a no-op there.
The Refresh button in the table's UI invalidates the cached data for that table, so the next load re-fetches and re-parses the file from its source URL.
View Configuration
When a CKAN administrator creates a Tables View manually, an optional File URL field is available in the view configuration form. If filled in, the data is fetched from that URL instead of the resource's own URL. This is useful when:
- The resource URL points to an HTML download page rather than a direct file link.
- You want to preview data from a different but related file.
If the field is left blank, the resource URL is used as-is.
Enabling the View
No additional setup is required beyond having the tables plugin enabled:
ckan.plugins = ... tables ...
Once active, the view is registered and will appear as Tables in the Add View dropdown on any resource whose format is supported.
Note
If you want the view to be added automatically for matching resources during resource creation or update, set CKAN's ckan.views.default_views configuration option:
ckan.views.default_views = tables_view