feat: add minimal OpenGraph links

cf #1591

umap/context_processors.py

@@ -7,6 +7,7 @@ def settings(request):
     return {
         "UMAP_FEEDBACK_LINK": djsettings.UMAP_FEEDBACK_LINK,
         "SITE_NAME": djsettings.SITE_NAME,
+        "SITE_URL": djsettings.SITE_URL,
         "ENABLE_ACCOUNT_LOGIN": djsettings.ENABLE_ACCOUNT_LOGIN,
         "UMAP_READONLY": djsettings.UMAP_READONLY,
         "UMAP_DEMO_SITE": djsettings.UMAP_DEMO_SITE,

umap/templates/umap/map_detail.html

@@ -18,6 +18,10 @@
         type="application/json+oembed"
         href="{{ oembed_absolute_uri }}?url={{ quoted_absolute_uri }}&format=json"
         title="{{ map.name }} oEmbed URL" />
+  <meta property="og:url" content="{{ SITE_URL }}{{ map.get_absolute_url }}" />
+  <meta property="og:title" content="{{ map.name }}" />
+  <meta property="og:description" content="{{ map.description }}" />
+  <meta property="og:site_name" content="{{ SITE_NAME }}" />
 {% endblock extra_head %}
 {% block content %}
   {% block map_init %}

umap/tests/test_map_views.py

@@ -847,3 +847,16 @@ def test_oembed_link(client, map, datalayer):
         f'?url=http%3A%2F%2Ftestserver%2Fen%2Fmap%2Ftest-map_{map.id}&format=json"'
     ) in response.content.decode()
     assert 'title="test map oEmbed URL" />' in response.content.decode()
+
+
+def test_ogp_links(client, map, datalayer):
+    response = client.get(map.get_absolute_url())
+    assert response.status_code == 200
+    content = response.content.decode()
+    assert (
+        f'<meta property="og:url" content="http://umap.org{map.get_absolute_url()}" />'
+        in content
+    )
+    assert f'<meta property="og:title" content="{map.name}" />' in content
+    assert f'<meta property="og:description" content="{map.description}" />' in content
+    assert '<meta property="og:site_name" content="uMap" />' in content