feat: add button for csv downloads

Use the secondary button style, as this is not a call to action, and
neither is it a link to another page.

home/urls.py

@@ -13,6 +13,11 @@
         views.metadata_specification_view,
         name="metadata_specification",
     ),
+    path(
+        "details/<str:result_type>/<str:urn>.csv",
+        views.details_view_csv,
+        name="details_csv",
+    ),
     path(
         "details/<str:result_type>/<str:urn>",
         views.details_view,

home/views.py

@@ -1,9 +1,10 @@
+import csv
 from urllib.parse import urlparse
 
 from data_platform_catalogue.client.exceptions import EntityDoesNotExist
 from data_platform_catalogue.search_types import DomainOption
 from django.conf import settings
-from django.http import Http404, HttpResponseBadRequest
+from django.http import Http404, HttpResponse, HttpResponseBadRequest
 from django.shortcuts import render
 from django.utils.translation import gettext as _
 from django.views.decorators.cache import cache_control
@@ -15,6 +16,11 @@
     DatabaseDetailsService,
     DatasetDetailsService,
 )
+from home.service.details_csv import (
+    DashboardDetailsCsvFormatter,
+    DatabaseDetailsCsvFormatter,
+    DatasetDetailsCsvFormatter,
+)
 from home.service.domain_fetcher import DomainFetcher
 from home.service.glossary import GlossaryService
 from home.service.metadata_specification import MetadataSpecificationService
@@ -55,6 +61,36 @@ def details_view(request, result_type, urn):
         raise Http404(f"{result_type} '{urn}' does not exist")
 
 
+@cache_control(max_age=300, private=True)
+def details_view_csv(request, result_type, urn) -> HttpResponse:
+    if result_type == "table":
+        service = DatasetDetailsService(urn)
+        csv_formatter = DatasetDetailsCsvFormatter(service)
+    elif result_type == "database":
+        service = DatabaseDetailsService(urn)
+        csv_formatter = DatabaseDetailsCsvFormatter(service)
+    elif result_type == "dashboard":
+        service = DashboardDetailsService(urn)
+        csv_formatter = DashboardDetailsCsvFormatter(service)
+    else:
+        raise Http404("CSV not available")
+
+    # In case there are any quotes in the filename, remove them in order to
+    # not to break the header.
+    unsavoury_characters = str.maketrans({'"': ""})
+    filename = urn.translate(unsavoury_characters) + ".csv"
+
+    response = HttpResponse(
+        content_type="text/csv",
+        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
+    )
+    writer = csv.writer(response)
+    writer.writerow(csv_formatter.headers())
+    writer.writerows(csv_formatter.data())
+
+    return response
+
+
 @cache_control(max_age=60, private=True)
 def search_view(request, page: str = "1"):
     new_search = request.GET.get("new", "")

templates/details_dashboard.html

@@ -33,6 +33,11 @@
             {% endfor %}
           </tbody>
         </table>
+        <form action="{% url 'home:details_csv' result_type='dashboard' urn=entity.urn %}">
+          <button type="submit" class="govuk-button govuk-button--secondary" data-module="govuk-button">
+            {% translate 'Download chart descriptions (CSV format)' %}
+          </button>
+        </form>
       {% else %}
         <h2 class="govuk-heading-m">{% translate "Dashboard content" %}</h2>
         <p class="govuk-body">{% translate "This dashboard is missing chart information." %}</p>

templates/details_database.html

@@ -39,6 +39,11 @@
             {% endfor %}
           </tbody>
         </table>
+        <form action="{% url 'home:details_csv' result_type='database' urn=entity.urn %}">
+          <button type="submit" class="govuk-button govuk-button--secondary" data-module="govuk-button">
+            {% translate 'Download table descriptions (CSV format)' %}
+          </button>
+        </form>
       {% else %}
         <h2 class="govuk-heading-m">{% translate "Database content" %}</h2>
         <p class="govuk-body">{% translate "This database is missing table information." %}</p>

templates/details_table.html

@@ -40,6 +40,12 @@
             {% endfor %}
           </tbody>
         </table>
+
+        <form action="{% url 'home:details_csv' result_type='table' urn=entity.urn %}">
+          <button type="submit" class="govuk-button govuk-button--secondary" data-module="govuk-button">
+            {% translate 'Download table schema (CSV format)' %}
+          </button>
+        </form>
       {% else %}
         <h2 class="govuk-heading-m">{% translate "Table schema" %}</h2>
         <p class="govuk-body">{% translate "The schema for this table is not available." %}</p>

tests/test_views.py

@@ -51,9 +51,65 @@ def test_table(self, client, switch_bool):
             response = client.get(
                 reverse("home:details", kwargs={"urn": "fake", "result_type": "table"})
             )
+
         assert response.status_code == 200
         assert response.headers["Cache-Control"] == "max-age=300, private"
 
+    @pytest.mark.django_db
+    def test_csv_output(self, client):
+        response = client.get(
+            reverse(
+                "home:details_csv",
+                kwargs={"urn": "fake", "result_type": "table"},
+            )
+        )
+        assert response.status_code == 200
+        assert (
+            response.headers["Content-Disposition"] == 'attachment; filename="fake.csv"'
+        )
+        assert response.content == (
+            b"name,display_name,is_primary_key,type,nullable,description\r\n"
+            + b"urn,urn,True,string,False,description **with markdown**\r\n"
+        )
+
+
+class TestDatabaseView:
+    @pytest.mark.django_db
+    def test_csv_output(self, client):
+        response = client.get(
+            reverse(
+                "home:details_csv",
+                kwargs={"urn": "fake", "result_type": "database"},
+            )
+        )
+        assert response.status_code == 200
+        assert (
+            response.headers["Content-Disposition"] == 'attachment; filename="fake.csv"'
+        )
+        assert response.content == (
+            b"urn,display_name,description\r\n"
+            + b"urn:li:dataset:fake_table,fake_table,table description\r\n"
+        )
+
+
+class TestDashboardView:
+    @pytest.mark.django_db
+    def test_csv_output(self, client):
+        response = client.get(
+            reverse(
+                "home:details_csv",
+                kwargs={"urn": "fake", "result_type": "dashboard"},
+            )
+        )
+        assert response.status_code == 200
+        assert (
+            response.headers["Content-Disposition"] == 'attachment; filename="fake.csv"'
+        )
+        assert response.content == (
+            b"urn,display_name,description\r\n"
+            + b"urn:li:chart:fake_chart,fake_chart,chart description\r\n"
+        )
+
 
 class TestChartView:
     def test_chart(self, client):