INTRODUCTION

govCMS CKAN provides integration with CKAN (http://ckan.org/). CKAN is a powerful data management system that makes data accessible by providing tools to streamline publishing, sharing, finding and using data.

Authors

This module was created by Jeremy Graham @ Doghouse Agency for GovCMS with assistance and guidance from Acquia and these contributors.

Submodules

govCMS CKAN Display

• Handles turning the tabular data into charts.
• Provides ability to download charts as svg/png.
• Provides visualisation plugins for common formats (eg. Bar, spline, line)

govCMS CKAN Display Examples

• Provides an examples page for viewing different chart types.

govCMS CKAN Media

• Provides media internet integration.
• Provides a CKAN file type and stream wrapper/handler.
• Visualisation configuration field/widget.
• Visualisation formatter/renderer.

GovCmsCkanClient Class

This client class handles fetching, caching and returning data from a CKAN endpoint.

The CKAN base URL and API key are configured via the admin UI. When an endpoint request is made it will first check if there is a local cached version and if not expired, will return that. If no cache exists or expired a new request to the endpoint is performed and cached.

Basic Usage of the class:

// Get a new instance of the class.
$client = govcms_ckan_client();

// Make a request.
$resource = 'action/package_show';
$query_params = array('id' => '1234');
$client->get($resource, $query_params);

This will make a request to the api which will look similar to this: http://my.ckan.enpoint.baseurl/api/3/action/package_show?id=1234

Valid responses:

The response object should always contain a valid property to indicate if the data returned is valid/usable. If FALSE there was either an error in the http request or possibly the CKAN request. All failed requests will get added to watchdog.

Examples of resources: action/package_show - metadata for a resource action/datastore_search - records (data) for a resource

Wrappers/Helpers:

// Return a resource metadata.
$meta = govcms_ckan_client_request_meta($resource_id);

// Return the records for a resource.
$records = govcms_ckan_client_request_records($resource_id);

GovCmsCkanDatasetParser Class

This parser class handles parsing the response records from the client class into table(s).

The parsed output is in a format for handing straight to theme_table either directly or by using a renderable array. Data can be represented in multiple ways, and this class provides setters to control how the data/table will be presented.

Basic usage of the class:

// Get a new instance of the class.
$parser = govcms_ckan_dataset_parser();

// Set the options.
$parser
  ->setResult($response_data)
  ->setKeys($keys)
  ->setLabelKey($label_key)
  ->setHeaderSource($x_axis_grouping)
  ->setTableAttributes($attributes)
  ->setGroupKey($group_key);
  ->parse();

GovCmsCkanDatasetParser.inc is well documented, see comments for what each setter does. You can also look at some of the visualisations used in govcms_ckan_display for working examples.

Visualisation plugins

Visualisations are cTools plugins, a module must implement the following for plugins to be registered:

function hook_ctools_plugin_directory($module, $plugin) {
  if ($module == 'govcms_ckan' && in_array($plugin, array_keys(govcms_ckan_ctools_plugin_type()))) {
    return 'plugins/' . $plugin;
  }
}

Visualisation plugins should live in the plugins/visualisations folder.

The best place to start with creating a new visualisation is by copying a visualisation from govcms_ckan_display/plugins/visualisation to your own module/theme and the customise.

Each plugin file should contain the following structure:

$plugin = array(
  'title' => 'My visualisation title',
  'settings' => array(),
);
function MODULE_NAME_PLUGIN_NAME_view($file, $display, $config){
  // Return renderable array of visualisation.
}
function MODULE_NAME_PLUGIN_NAME_configure($plugin, $form, $form_state, $config){
  // Return form structure array for configuration elements.
}

Configuration helpers:

There is a few helpers that include common structure/elements for visualisation configure forms. The intention is a plugin configuration form will include these as required.

  // Include default widgets.
  $widgets = array(
    'govcms_ckan_media_visualisation_default_key_config',
    'govcms_ckan_media_visualisation_default_axis_config',
    'govcms_ckan_media_visualisation_default_grid_config',
    'govcms_ckan_media_visualisation_default_chart_config',
  );
  $config_form = govcms_ckan_media_visualisation_include_form_widgets($form, $form_state, $config, $widgets);

Adding custom stlyes to exported charts

Exported charts (Download as PNG/SVG) must have the css embedded in the SVG, as you may want to add additional styling to the exported files, govcms_ckan_display provides a way for you add your own external stylesheets that get embedded for export. Example:

  drupal_add_js(array(
    'govcmsCkanDisplay' => array(
      'exportStylesheets' => array(url('path/to/custom/css/graph_export.css')),
    ),
  ), 'setting');

NOTE: This requires jQuery 1.5+