From c62c15ede6e8980ef2eccf067beab88303e028ea Mon Sep 17 00:00:00 2001
From: Mark Longair <mhl@pobox.com>
Date: Mon, 2 Oct 2017 10:18:03 +0100
Subject: [PATCH] Add support for a 'country' filter in query parameters

This change means that you can add '?country=E' (say) to queries for
multiple areas to restrict the results to those areas that have a
Country with code 'E'.

This should be particularly helpful for global.mapit.mysociety.org
if we set an appropriate Country for each Area, since one is almost
always interested in results from a particular country.

Fixes #55
---
 mapit/templates/mapit/api/areas.html |  1 +
 mapit/templates/mapit/api/point.html |  5 +++++
 mapit/tests/test_query_args.py       | 22 ++++++++++++++++++++++
 mapit/views/areas.py                 | 13 +++++++++----
 4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/mapit/templates/mapit/api/areas.html b/mapit/templates/mapit/api/areas.html
index e20ef999..d9978d89 100644
--- a/mapit/templates/mapit/api/areas.html
+++ b/mapit/templates/mapit/api/areas.html
@@ -23,6 +23,7 @@ <h3>{% blocktrans trimmed %}
                 <li><i>generation</i>, {% trans "to return areas in that generation (type and name lookups only)" %}.</li>
                 <li><i>min_generation</i>, {% trans "to return areas since that generation (type and name lookups only)" %}.</li>
                 <li><i>type</i>, {% trans "to restrict results to a type or types (multiple separated by commas; name lookup only)" %}.</li>
+                <li><i>country</i>, {% trans "to restrict results to areas with particular country codes (multiple separated by commas; type and name lookups only)" %}.</li>
             </ul></dd>
 
             <dt>{% trans "Returns" %}:</dt>
diff --git a/mapit/templates/mapit/api/point.html b/mapit/templates/mapit/api/point.html
index 072659bd..27155110 100644
--- a/mapit/templates/mapit/api/point.html
+++ b/mapit/templates/mapit/api/point.html
@@ -58,6 +58,11 @@ <h3>{% blocktrans trimmed %}
                                 <i>min_generation</i>, to return results since that generation.
                             {% endblocktrans %}
                         </li>
+                        <li>
+                            {% blocktrans trimmed %}
+                                <i>country</i>, to restrict results to areas with particular country codes (multiple country codes separated by commas).
+                            {% endblocktrans %}
+                        </li>
                     </ul>
                 </dd>
 
diff --git a/mapit/tests/test_query_args.py b/mapit/tests/test_query_args.py
index 92a7fe6e..e2ee19e9 100644
--- a/mapit/tests/test_query_args.py
+++ b/mapit/tests/test_query_args.py
@@ -108,3 +108,25 @@ def test_min_generation_specified(self):
                 'generation_low__lte': self.active_generation.id,
             }
         )
+
+    def test_one_country_in_query(self):
+        args = query_args(FakeRequest({'country': 'DE'}), 'json', None)
+        self.assertEqual(
+            args,
+            {
+                'generation_high__gte': self.active_generation.id,
+                'generation_low__lte': self.active_generation.id,
+                'country__code': 'DE',
+            }
+        )
+
+    def test_two_countries_in_query(self):
+        args = query_args(FakeRequest({'country': 'DE,FR'}), 'json', None)
+        self.assertEqual(
+            args,
+            {
+                'generation_high__gte': self.active_generation.id,
+                'generation_low__lte': self.active_generation.id,
+                'country__code__in': ['DE', 'FR'],
+            }
+        )
diff --git a/mapit/views/areas.py b/mapit/views/areas.py
index a70ebf71..6ff9a2f3 100644
--- a/mapit/views/areas.py
+++ b/mapit/views/areas.py
@@ -64,6 +64,7 @@ def query_args(request, format, type=None):
 
     if type is None:
         type = request.GET.get('type', '')
+    country_code = request.GET.get('country', '')
 
     args = {}
     if min_generation > -1:
@@ -71,10 +72,14 @@ def query_args(request, format, type=None):
             'generation_low__lte': generation,
             'generation_high__gte': min_generation,
         }
-    if ',' in type:
-        args['type__code__in'] = type.split(',')
-    elif type:
-        args['type__code'] = type
+    for attr, value in [
+            ('type', type),
+            ('country', country_code),
+    ]:
+        if ',' in value:
+            args[attr + '__code__in'] = value.split(',')
+        elif value:
+            args[attr + '__code'] = value
 
     return args