[#45] Hook into the custom spatial previewer

A custom helper function checks if the format is one of the ones
supported by the external viewer maintained by GMU. The viewer URL and
the supported formats can be defined via config options.

ckanext.geodatagov.spatial_preview.url
ckanext.geodatagov.spatial_preview.formats

Support for a future default_srs parameter has been added.

ckanext/geodatagov/helpers.py

@@ -1,4 +1,8 @@
+import urllib
 import logging
+
+from pylons import config
+
 from ckan import plugins as p
 from ckan.lib import helpers as h
 
@@ -72,3 +76,27 @@ def get_harvest_source_link(package_dict):
        return p.toolkit.literal(link)
 
     return ''
+
+def resource_preview_custom(resource, pkg_id):
+
+    viewer_url = config.get('ckanext.geodatagov.spatial_preview.url')
+    formats = config.get('ckanext.geodatagov.spatial_preview.formats', 'wms kml kmz').strip().split(' ')
+
+    if viewer_url and resource.get('url') and resource.get('format','').lower() in formats:
+        params= {
+            'url': resource['url'],
+            'serviceType': resource['format'].lower(),
+        }
+        if resource.get('default_srs'):
+            params['srs'] = resource['default_srs']
+
+        url = '{viewer_url}?{params}'.format(
+                viewer_url=viewer_url,
+                params=urllib.urlencode(params))
+
+        return p.toolkit.render_snippet("dataviewer/snippets/data_preview.html",
+               data={'embed': False,
+               'resource_url': url,
+               'raw_resource_url': resource['url']})
+
+    return h.resource_preview(resource, pkg_id)

ckanext/geodatagov/plugins.py

@@ -198,6 +198,7 @@ def get_helpers(self):
                 'get_harvest_source_link': geodatagov_helpers.get_harvest_source_link,
                 'get_validation_profiles': geodatagov_helpers.get_validation_profiles,
                 'get_collection_package': geodatagov_helpers.get_collection_package,
+                'resource_preview_custom': geodatagov_helpers.resource_preview_custom,
                 }
 
     ## IActions

ckanext/geodatagov/templates/package/resource_read.html

@@ -0,0 +1,5 @@
+{% ckan_extends %}
+
+{% block data_preview %}
+  {{ h.resource_preview_custom(c.resource, c.package.id) }}
+{% endblock %}