Add min_generation parameter to postcode lookup.

mapit/models.py

@@ -9,9 +9,11 @@
 from django.db.models.query import RawQuerySet
 from django.utils.encoding import smart_str
 from django.utils.functional import cached_property
+from django.utils.translation import gettext as _
 
 from mapit import countries
 from mapit.geometryserialiser import GeometrySerialiser
+from mapit.middleware import ViewException
 
 
 def materialized():
@@ -44,6 +46,23 @@ def new(self):
             return None
         return latest[0]
 
+    def query_args(self, request, format):
+        try:
+            generation = int(request.GET.get('generation', 0))
+        except ValueError:
+            raise ViewException(format, _('Bad generation specified'), 400)
+        if not generation:
+            generation = self.current().id
+
+        try:
+            min_generation = int(request.GET.get('min_generation', 0))
+        except ValueError:
+            raise ViewException(format, _('Bad min_generation specified'), 400)
+        if not min_generation:
+            min_generation = generation
+
+        return generation, min_generation
+
 
 class Generation(models.Model):
 
@@ -148,13 +167,11 @@ def by_location(self, location, generation=None):
             generation_low__lte=generation, generation_high__gte=generation
         )
 
-    def by_postcode(self, postcode, generation=None):
-        if not generation:
-            generation = Generation.objects.current()
+    def by_postcode(self, postcode, generation, min_generation):
         return list(itertools.chain(
             self.by_location(postcode.location, generation),
             postcode.areas.filter(
-                generation_low__lte=generation, generation_high__gte=generation
+                generation_low__lte=generation, generation_high__gte=min_generation
             )
         ))
 

mapit/templates/mapit/api/postcode.html

@@ -19,11 +19,15 @@ <h3>
         </dd>
 
         <dt>{% trans "Optional query parameters" %}:</dt>
-        <dd>
+        <dd><ul><li>
             {% blocktrans trimmed %}
-                <p><i>generation</i>, to return results from a previous generation.</p>
+                <i>generation</i>, to return results from a previous generation.
             {% endblocktrans %}
-        </dd>
+            </li><li>
+            {% blocktrans trimmed %}
+                <i>min_generation</i>, to return results since that generation.
+            {% endblocktrans %}
+        </li></ul></dd>
 
         {% include "mapit/api/postcode-example.html" %}
     </dl>

mapit/tests/test_query_args.py

@@ -130,3 +130,16 @@ def test_two_countries_in_query(self):
                 generation_low__lte=self.active_generation.id,
             ) & (Q() | Q(country__code__in=['DE', 'FR']) | Q(countries__code__in=['DE', 'FR']))
         )
+
+    def test_generation_manager_query_args(self):
+        gen, min_gen = Generation.objects.query_args(
+            FakeRequest({'generation': self.old_generation.id}),
+            'json')
+        self.assertEqual(gen, self.old_generation.id)
+        self.assertEqual(min_gen, self.old_generation.id)
+
+        gen, min_gen = Generation.objects.query_args(
+            FakeRequest({'min_generation': self.old_generation.id}),
+            'json')
+        self.assertEqual(min_gen, self.old_generation.id)
+        self.assertEqual(gen, self.active_generation.id)

mapit/views/areas.py

@@ -60,19 +60,7 @@ def output_areas(request, title, format, areas, **kwargs):
 
 
 def query_args(request, format, type=None):
-    try:
-        generation = int(request.GET.get('generation', 0))
-    except ValueError:
-        raise ViewException(format, _('Bad generation specified'), 400)
-    if not generation:
-        generation = Generation.objects.current().id
-
-    try:
-        min_generation = int(request.GET.get('min_generation', 0))
-    except ValueError:
-        raise ViewException(format, _('Bad min_generation specified'), 400)
-    if not min_generation:
-        min_generation = generation
+    generation, min_generation = Generation.objects.query_args(request, format)
 
     if type is None:
         type = request.GET.get('type', '')

mapit/views/postcodes.py

@@ -67,12 +67,11 @@ def postcode(request, postcode, format=None):
     if not is_valid_postcode(postcode):
         raise ViewException(format, "Postcode '%s' is not valid." % postcode, 400)
     postcode = get_object_or_404(Postcode, format=format, postcode=postcode)
-    try:
-        generation = int(request.GET['generation'])
-    except:
-        generation = Generation.objects.current()
+
+    generation, min_generation = Generation.objects.query_args(request, format)
+
     if not hasattr(countries, 'is_special_postcode') or not countries.is_special_postcode(postcode.postcode):
-        areas = list(add_codes(Area.objects.by_postcode(postcode, generation)))
+        areas = list(add_codes(Area.objects.by_postcode(postcode, generation, min_generation)))
     else:
         areas = []