Add spatial search based on PostGIS for packages with geographic extent

ckanext/harvest/__init__.py

@@ -66,7 +66,11 @@ class Harvest(SingletonPlugin):
         map.connect('harvest_create', '/harvest/:id/refresh',
             controller='ckanext.harvest.controllers.view:ViewController',
             action='create_harvesting_job')
-       
+
+        map.connect('api_spatial_query', '/api/2/search/package/geo',
+            controller='ckanext.harvest.controllers.api:ApiController',
+            action='spatial_query')
+      
         return map
 
     def update_config(self, config):

ckanext/harvest/controllers/api.py

@@ -0,0 +1,80 @@
+from ckan.lib.helpers import json
+import ckan.lib.helpers as h
+from ckan.lib.base import c, g, request, \
+                          response, session, render, config, abort, redirect
+from ckan.controllers.rest import BaseApiController
+
+
+from ckan.model import Session
+
+
+class ApiController(BaseApiController):
+    def _get_srid(self,crs):
+        """Returns the SRID for the provided CRS definition
+            The CRS can be defined in the following formats
+            - urn:ogc:def:crs:EPSG::4258
+            - EPSG:4258
+            - 4258
+           """
+
+        if ':' in crs:
+            crs = crs.split(':')
+            srid = crs[len(crs)-1]
+        else:
+           srid = crs
+
+        return int(srid)
+
+
+    def spatial_query(self):
+        if not 'bbox' in request.params:
+            abort(400)
+        
+        bbox = request.params['bbox'].split(',')
+        if len(bbox) is not 4:
+            abort(400)
+        
+        minx = float(bbox[0])
+        miny = float(bbox[1])
+        maxx = float(bbox[2])
+        maxy = float(bbox[3])
+
+        params = {'minx':minx,'miny':miny,'maxx':maxx,'maxy':maxy}
+
+        if 'crs' in request.params:
+            # The input bounding box is defined in another projection, we need
+            # to transform it
+            srid = self._get_srid(request.params['crs'])
+
+            statement = """SELECT package_id FROM package_extent WHERE 
+                            ST_Intersects(
+                                ST_Transform(
+                                    ST_GeomFromText('POLYGON ((%(minx)s %(miny)s, 
+                                                        %(maxx)s %(miny)s,
+                                                        %(maxx)s %(maxy)s,
+                                                        %(minx)s %(maxy)s,
+                                                        %(minx)s %(miny)s))',%(srid)s),
+                                    4258)
+                                ,the_geom)"""
+            params.update({'srid': srid})
+        else:
+            statement = """SELECT package_id FROM package_extent WHERE 
+                            ST_Intersects(
+                                ST_GeomFromText('POLYGON ((%(minx)s %(miny)s, 
+                                                        %(maxx)s %(miny)s,
+                                                        %(maxx)s %(maxy)s,
+                                                        %(minx)s %(maxy)s,
+                                                        %(minx)s %(miny)s))',4258),
+                                the_geom)"""
+        try:
+            conn = Session.connection()
+            rows = conn.execute(statement,params)
+            ids = [row['package_id'] for row in rows]
+        
+            output = dict(count=len(ids),results=ids)
+
+            return self._finish_ok(output)
+        except:    
+            abort(500)
+
+