A custom serializer that outputs object_detail and object_list endpoints in KML, GeoJSON and SHP

boundaryservice/resources.py

@@ -3,32 +3,50 @@
 from django.contrib.gis.measure import D
 from tastypie import fields
 from tastypie.serializers import Serializer
+from boundaryservice.serializers import BoundaryGeoSerializer
+from boundaryservice.serializers import BoundarySetGeoSerializer
 
 from boundaryservice.authentication import NoOpApiKeyAuthentication
 from boundaryservice.models import BoundarySet, Boundary
 from boundaryservice.tastyhacks import SluggedResource
 from boundaryservice.throttle import AnonymousThrottle
 
+
 class BoundarySetResource(SluggedResource):
     boundaries = fields.ToManyField('boundaryservice.resources.BoundaryResource', 'boundaries')
 
     class Meta:
         queryset = BoundarySet.objects.all()
-        serializer = Serializer(formats=['json', 'jsonp'], content_types = {'json': 'application/json', 'jsonp': 'text/javascript'})
+        serializer = BoundarySetGeoSerializer()
         resource_name = 'boundary-set'
         excludes = ['id', 'singular', 'kind_first']
         allowed_methods = ['get']
         authentication = NoOpApiKeyAuthentication()
         #throttle = AnonymousThrottle(throttle_at=100) 
+
+    def alter_list_data_to_serialize(self, request, data):
+        """
+        Allow the selection of simple, full or no shapes using a query parameter.
+        """
+        data['shape_type'] = request.GET.get('shape_type', 'simple')
+        return data
+
+    def alter_detail_data_to_serialize(self, request, bundle):
+        """
+        Allow the selection of simple, full or no shapes using a query parameter.
+        """
+        bundle.shape_type = request.GET.get('shape_type', 'simple')
+        return bundle
+
 
 class BoundaryResource(SluggedResource):
     set = fields.ForeignKey(BoundarySetResource, 'set')
 
     class Meta:
         queryset = Boundary.objects.all()
-        serializer = Serializer(formats=['json', 'jsonp'], content_types = {'json': 'application/json', 'jsonp': 'text/javascript'})
+        serializer = BoundaryGeoSerializer()
         resource_name = 'boundary'
-        excludes = ['id', 'display_name']
+        excludes = ['id', 'display_name', 'centroid']
         allowed_methods = ['get']
         authentication = NoOpApiKeyAuthentication()
         #throttle = AnonymousThrottle(throttle_at=100) 
@@ -38,28 +56,24 @@ def alter_list_data_to_serialize(self, request, data):
         Allow the selection of simple, full or no shapes using a query parameter.
         """
         shape_type = request.GET.get('shape_type', 'simple')
-
+        data['shape_type'] = 'shape'
         for obj in data['objects']:
-            if shape_type != 'simple':
+            if shape_type == 'full':
                 del obj.data['simple_shape']
-
-            if shape_type != 'full':
+            else:
                 del obj.data['shape']
-
         return data
 
     def alter_detail_data_to_serialize(self, request, bundle):
         """
         Allow the selection of simple, full or no shapes using a query parameter.
         """
         shape_type = request.GET.get('shape_type', 'simple')
-
-        if shape_type != 'simple':
+        bundle.shape_type = shape_type
+        if shape_type == 'full':
             del bundle.data['simple_shape']
-
-        if shape_type != 'full':
+        else:
             del bundle.data['shape']
-
         return bundle
 
     def build_filters(self, filters=None):

boundaryservice/serializers.py

@@ -0,0 +1,259 @@
+import json
+from tastypie.bundle import Bundle
+from tastypie.serializers import Serializer
+from boundaryservice.shp import ShpSerializer
+from django.template.loader import render_to_string
+from django.core.serializers.json import DjangoJSONEncoder
+
+
+class BaseGeoSerializer(Serializer):
+    """
+    Adds some common geospatial outputs to the standard serializer.
+
+    Supported formats:
+
+        * JSON (Standard issue)
+        * JSONP (Standard issue)
+        * KML
+        * GeoJSON
+
+    """
+    formats = [
+        'json',
+        'jsonp',
+        'kml',
+        'geojson',
+        'shp',
+    ]
+    content_types = {
+        'json': 'application/json',
+        'jsonp': 'text/javascript',
+        'kml': 'application/vnd.google-earth.kml+xml',
+        'geojson': 'application/geo+json',
+        'shp': 'application/zip',
+    }
+
+    def get_shape_attr(self, shape_type):
+        """
+        Which shape attribute the user would like us to return.
+        """
+        if shape_type == 'full':
+            return 'shape'
+        else:
+            return 'simple_shape'
+
+
+class BoundarySetGeoSerializer(BaseGeoSerializer):
+    """
+    Applies the geospatial serializer to the BoundarySet model.
+    """
+    def to_shp(self, data, options=None):
+        """
+        Converts the bundle to a SHP serialization.
+        """
+        simple_obj = self.to_simple(data, options)
+        if isinstance(data, dict):
+            # List data
+            shape_attr = self.get_shape_attr(data['shape_type'])
+            boundary_list = []
+            for bset in data['objects']:
+                for boundary in bset.obj.boundaries.all():
+                    boundary_list.append(boundary)
+            return ShpSerializer(
+                queryset=boundary_list,
+                geo_field=shape_attr,
+                excludes=['id', 'singular', 'kind_first', 'metadata'],
+            )()
+        elif isinstance(data, Bundle):
+            # Detail data
+            shape_attr = self.get_shape_attr(data.shape_type)
+            boundary_list = []
+            for boundary in data.obj.boundaries.all():
+                boundary_list.append(boundary)
+            return ShpSerializer(
+                queryset=boundary_list,
+                geo_field=shape_attr,
+                readme=simple_obj['notes'],
+                file_name=boundary_list[0].kind.lower(),
+                excludes=['id', 'singular', 'kind_first', 'metadata'],
+            )()
+
+    def to_geojson(self, data, options=None):
+        """
+        Converts the bundle to a GeoJSON seralization.
+        """
+        # Hook the GeoJSON output to the object
+        simple_obj = self.to_simple(data, options)
+        if isinstance(data, dict):
+            # List data
+            shape_attr = self.get_shape_attr(data['shape_type'])
+            boundary_list = []
+            for bset in data['objects']:
+                simple_bset = self.to_simple(bset, options)
+                for boundary in bset.obj.boundaries.all():
+                    boundary.geojson = getattr(boundary, shape_attr).geojson
+                    boundary.set_uri = simple_bset['resource_uri']
+                    api_name = "".join(boundary.set_uri.split("/")[:2])
+                    boundary.resource_uri = "/%s/boundary/%s/" % (api_name, boundary.slug)
+                    boundary_list.append(boundary)
+            geojson = json.loads(render_to_string('object_list.geojson', {
+                'boundary_list': boundary_list,
+            }))
+            response_dict = dict(meta=simple_obj['meta'], geojson=geojson)
+            return json.dumps(
+                response_dict,
+                cls=DjangoJSONEncoder,
+                sort_keys=False,
+                ensure_ascii=False
+            )
+        elif isinstance(data, Bundle):
+            shape_attr = self.get_shape_attr(data.shape_type)
+            # Clean up the boundaries
+            boundary_list = []
+            for boundary in data.obj.boundaries.all():
+                boundary.geojson = getattr(boundary, shape_attr).geojson
+                boundary.set_uri = simple_obj['resource_uri']
+                api_name = "".join(boundary.set_uri.split("/")[:2])
+                boundary.resource_uri = "/%s/boundary/%s/" % (api_name, boundary.slug)
+                boundary_list.append(boundary)
+            # Render the result using a template and pass it out
+            return render_to_string('object_list.geojson', {
+                'boundary_list': boundary_list,
+            })
+
+    def to_kml(self, data, options=None):
+        """
+        Converts the bundle to a KML serialization.
+        """
+        # Hook the GeoJSON output to the object
+        simple_obj = self.to_simple(data, options)
+        if isinstance(data, dict):
+            # List data
+            shape_attr = self.get_shape_attr(data['shape_type'])
+            boundary_list = []
+            for bset in data['objects']:
+                simple_bset = self.to_simple(bset, options)
+                for boundary in bset.obj.boundaries.all():
+                    boundary.kml = getattr(boundary, shape_attr).kml
+                    boundary.set_uri = simple_bset['resource_uri']
+                    api_name = "".join(boundary.set_uri.split("/")[:2])
+                    boundary.resource_uri = "/%s/boundary/%s/" % (api_name, boundary.slug)
+                    boundary_list.append(boundary)
+            return render_to_string('object_list.kml', {
+                'boundary_list': boundary_list,
+            })
+        elif isinstance(data, Bundle):
+            shape_attr = self.get_shape_attr(data.shape_type)
+            # Clean up the boundaries
+            boundary_list = []
+            for boundary in data.obj.boundaries.all():
+                boundary.kml = getattr(boundary, shape_attr).kml
+                boundary.set_uri = simple_obj['resource_uri']
+                api_name = "".join(boundary.set_uri.split("/")[:2])
+                boundary.resource_uri = "/%s/boundary/%s/" % (api_name, boundary.slug)
+                boundary_list.append(boundary)
+            # Render the result using a template and pass it out
+            return render_to_string('object_list.kml', {
+                'boundary_list': boundary_list,
+            })
+
+
+class BoundaryGeoSerializer(BaseGeoSerializer):
+    """
+    Applies the geospatial serializer to the Boundary model.
+    """
+    def to_shp(self, data, options=None):
+        """
+        Converts the bundle to a SHP serialization.
+        """
+        # Hook the KML output to the object
+        simple_obj = self.to_simple(data, options)
+        # Figure out if it's list data or detail data
+        if isinstance(data, dict):
+            # List data
+            shape_attr = self.get_shape_attr(data['shape_type'])
+            boundary_list = []
+            for bundle in data['objects']:
+                boundary_list.append(bundle.obj)
+            return ShpSerializer(
+                queryset=boundary_list,
+                geo_field=shape_attr,
+                excludes=['id', 'singular', 'kind_first', 'metadata'],
+            )()
+
+        elif isinstance(data, Bundle):
+            # Detail data
+            shape_attr = self.get_shape_attr(data.shape_type)
+            simple_obj['kml'] = getattr(data.obj, shape_attr).kml
+            return ShpSerializer(
+                queryset=[data.obj],
+                geo_field=shape_attr,
+                file_name=data.obj.kind.lower(),
+                excludes=['id', 'singular', 'kind_first', 'metadata'],
+            )()
+
+    def to_geojson(self, data, options=None):
+        """
+        Converts the bundle to a GeoJSON seralization.
+        """
+        simple_obj = self.to_simple(data, options)
+        # Figure out if it's list data or detail data
+        if isinstance(data, dict):
+            # List data
+            shape_attr = self.get_shape_attr(data['shape_type'])
+            boundary_list = []
+            for bundle in data['objects']:
+                simple_boundary = self.to_simple(bundle, options)
+                simple_boundary['geojson'] = getattr(bundle.obj, shape_attr).geojson
+                simple_boundary['set_uri'] = simple_boundary['set']
+                boundary_list.append(simple_boundary)
+            geojson = json.loads(render_to_string('object_list.geojson', {
+                'boundary_list': boundary_list,
+            }))
+            response_dict = dict(meta=simple_obj['meta'], geojson=geojson)
+            return json.dumps(
+                response_dict,
+                cls=DjangoJSONEncoder,
+                sort_keys=False,
+                ensure_ascii=False
+            )
+
+        elif isinstance(data, Bundle):
+            # Detail data
+            shape_attr = self.get_shape_attr(data.shape_type)
+            simple_obj['geojson'] = getattr(data.obj, shape_attr).geojson
+            simple_obj['set_uri'] = simple_obj['set']
+            # Render the result using a template and pass it out
+            return render_to_string('object_detail.geojson', {
+                'obj': simple_obj,
+            })
+
+    def to_kml(self, data, options=None):
+        """
+        Converts the bundle to a KML serialization.
+        """
+        # Hook the KML output to the object
+        simple_obj = self.to_simple(data, options)
+        # Figure out if it's list data or detail data
+        if isinstance(data, dict):
+            # List data
+            shape_attr = self.get_shape_attr(data['shape_type'])
+            boundary_list = []
+            for bundle in data['objects']:
+                simple_boundary = self.to_simple(bundle, options)
+                simple_boundary['kml'] = getattr(bundle.obj, shape_attr).kml
+                simple_boundary['set_uri'] = simple_boundary['set']
+                boundary_list.append(simple_boundary)
+            return render_to_string('object_list.kml', {
+                'boundary_list': boundary_list,
+            })
+
+        elif isinstance(data, Bundle):
+            # Detail data
+            shape_attr = self.get_shape_attr(data.shape_type)
+            simple_obj['kml'] = getattr(data.obj, shape_attr).kml
+            simple_obj['set_uri'] = simple_obj['set']
+            # Render the result using a template and pass it out
+            return render_to_string('object_detail.kml', {
+                'obj': simple_obj,
+            })